Publications by authors named "Elena Crespo"

37 Publications

Donor/Recipient HLA Molecular Mismatch Scores Predict Primary Humoral and Cellular Alloimmunity in Kidney Transplantation.

Front Immunol 2020 10;11:623276. Epub 2021 Mar 10.

Kidney Transplant Unit, Nephrology Department, Bellvitge University Hospital, Barcelona, Spain.

Donor/recipient molecular human leukocyte antigen (HLA) mismatch predicts primary B-cell alloimmune activation, yet the impact on donor-specific T-cell alloimmunity (dnDST) remains undetermined. The hypothesis of our study is that donor/recipient HLA mismatches assessed at the molecular level may also influence a higher susceptibility to the development of posttransplant primary T-cell alloimmunity. In this prospective observational study, 169 consecutive kidney transplant recipients without preformed donor-specific antibodies (DSA) and with high resolution donor/recipient HLA typing were evaluated for HLA molecular mismatch scores using different informatic algorithms [amino acid mismatch, eplet MM, and Predicted Indirectly Recognizable HLA Epitopes (PIRCHE-II)]. Primary donor-specific alloimmune activation over the first 2 years posttransplantation was assessed by means of both dnDSA and dnDST using single antigen bead (SAB) and IFN-γ ELISPOT assays, respectively. Also, the predominant alloantigen presenting pathway priming DST alloimmunity and the contribution of main alloreactive T-cell subsets were further characterized . Pretransplantation, 78/169 (46%) were DST+ whereas 91/169 (54%) DST-. At 2 years, 54/169 (32%) patients showed detectable DST responses: 23/54 (42%) dnDST and 31/54 (57%) persistently positive (persistDST+). 24/169 (14%) patients developed dnDSA. A strong correlation was observed between the three distinct molecular mismatch scores and they all accurately predicted dnDSA formation, in particular at the DQ locus. Likewise, HLA molecular incompatibility predicted the advent of dnDST, especially when assessed by PIRCHE-II score (OR 1.014 95% CI 1.001-1.03, p=0.04). While pretransplant DST predicted the development of posttransplant BPAR (OR 5.18, 95% CI=1.64-16.34, p=0.005) and particularly T cell mediated rejection (OR 5.33, 95% CI=1.45-19.66, p=0.012), patients developing dnDST were at significantly higher risk of subsequent dnDSA formation (HR 2.64, 95% CI=1.08-6.45, p=0.03). experiments showed that unlike preformed DST that is predominantly primed by CD8+ direct pathway T cells, posttransplant DST may also be activated by the indirect pathway of alloantigen presentation, and predominantly driven by CD4+ alloreactive T cells in an important proportion of patients. donor-specific cellular alloreactivity seems to precede subsequent humoral alloimmune activation and is influenced by a poor donor/recipient HLA molecular matching.
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http://dx.doi.org/10.3389/fimmu.2020.623276DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7988214PMC
March 2021

SARS-CoV-2-specific serological and functional T cell immune responses during acute and early COVID-19 convalescence in solid organ transplant patients.

Am J Transplant 2021 Mar 23. Epub 2021 Mar 23.

Kidney Transplant Unit, Bellvitge University Hospital, Barcelona, Spain.

The description of protective humoral and T cell immune responses specific against SARS-CoV-2 has been reported among immunocompetent (IC) individuals developing COVID-19 infection. However, its characterization and determinants of poorer outcomes among the at-risk solid organ transplant (SOT) patient population have not been thoroughly investigated. Cytokine-producing T cell responses, such as IFN-γ, IL-2, IFN-γ/IL-2, IL-6, IL-21, and IL-5, against main immunogenic SARS-CoV-2 antigens and IgM/IgG serological immunity were tracked in SOT (n = 28) during acute infection and at two consecutive time points over the following 40 days of convalescence and were compared to matched IC (n = 16) patients admitted with similar moderate/severe COVID-19. We describe the development of a robust serological and functional T cell immune responses against SARS-CoV-2 among SOT patients, similar to IC patients during early convalescence. However, at the infection onset, SOT displayed lower IgG seroconversion rates (77% vs. 100%; p = .044), despite no differences on IgG titers, and a trend toward decreased SARS-CoV-2-reactive T cell frequencies, especially against the membrane protein (7 [0-34] vs. 113 [15-245], p = .011, 2 [0-9] vs. 45 [5-74], p = .009, and 0 [0-2] vs. 13 [1-24], p = .020, IFN-γ, IL-2, and IFN-γ/IL-2 spots, respectively). In summary, our data suggest that despite a certain initial delay, SOT population achieve comparable functional immune responses than the general population after moderate/severe COVID-19.
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http://dx.doi.org/10.1111/ajt.16570DOI Listing
March 2021

Preformed T cell alloimmunity and HLA eplet mismatch to guide immunosuppression minimization with tacrolimus monotherapy in kidney transplantation: Results of the CELLIMIN trial.

Am J Transplant 2021 Mar 16. Epub 2021 Mar 16.

Transplantation Research and Immunology Group, Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.

Personalizing immunosuppression is a major objective in transplantation. Transplant recipients are heterogeneous regarding their immunological memory and primary alloimmune susceptibility. This biomarker-guided trial investigated whether in low immunological-risk kidney transplants without pretransplant DSA and donor-specific T cells assessed by a standardized IFN-γ ELISPOT, low immunosuppression (LI) with tacrolimus monotherapy would be non-inferior regarding 6-month BPAR than tacrolimus-based standard of care (SOC). Due to low recruitment rates, the trial was terminated when 167 patients were enrolled. ELISPOT negatives (E-) were randomized to LI (n = 48) or SOC (n = 53), E+ received the same SOC. Six- and 12-month BPAR rates were higher among LI than SOC/E- (4/35 [13%] vs. 1/43 [2%], p = .15 and 12/48 [25%] vs. 6/53 [11.3%], p = .073, respectively). E+ patients showed similarly high BPAR rates than LI at 6 and 12 months (12/55 [22%] and 13/66 [20%], respectively). These differences were stronger in per-protocol analyses. Post-hoc analysis revealed that poor class-II eplet matching, especially DQ, discriminated E- patients, notably E-/LI, developing BPAR (4/28 [14%] low risk vs. 8/20 [40%] high risk, p = .043). Eplet mismatch also predicted anti-class-I (p = .05) and anti-DQ (p < .001) de novo DSA. Adverse events were similar, but E-/LI developed fewer viral infections, particularly polyoma-virus-associated nephropathy (p = .021). Preformed T cell alloreactivity and HLA eplet mismatch assessment may refine current baseline immune-risk stratification and guide immunosuppression decision-making in kidney transplantation.
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http://dx.doi.org/10.1111/ajt.16563DOI Listing
March 2021

Dual and Opposite Costimulatory Targeting with a Novel Human Fusion Recombinant Protein Effectively Prevents Renal Warm Ischemia Reperfusion Injury and Allograft Rejection in Murine Models.

Int J Mol Sci 2021 Jan 26;22(3). Epub 2021 Jan 26.

Nephrology Department, Bellvitge University Hospital, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.

Many studies have shown both the CD28-D80/86 costimulatory pathway and the PD-1-PD-L1/L2 coinhibitory pathway to be important signals in modulating or decreasing the inflammatory profile in ischemia-reperfusion injury (IRI) or in a solid organ transplant setting. The importance of these two opposing pathways and their potential synergistic effect led our group to design a human fusion recombinant protein with CTLA4 and PD-L2 domains named HYBRI. The objective of our study was to determine the HYBRI binding to the postulated ligands of CTLA4 (CD80) and PD-L2 (PD-1) using the Surface Plasmon Resonance technique and to evaluate the in vivo HYBRI effects on two representative kidney inflammatory models-rat renal IRI and allogeneic kidney transplant. The Surface Plasmon Resonance assay demonstrated the avidity and binding of HYBRI to its targets. HYBRI treatment in the models exerted a high functional and morphological improvement. HYBRI produced a significant amelioration of renal function on day one and two after bilateral warm ischemia and on days seven and nine after transplant, clearly prolonging the animal survival in a life-sustaining renal allograft model. In both models, a significant reduction in histological damage and CD3 and CD68 infiltrating cells was observed. HYBRI decreased the circulating inflammatory cytokines and enriched the FoxP3 peripheral circulating, apart from reducing renal inflammation. In conclusion, the dual and opposite costimulatory targeting with that novel protein offers a good microenvironment profile to protect the ischemic process in the kidney and to prevent the kidney rejection, increasing the animal's chances of survival. HYBRI largely prevents the progression of inflammation in these rat models.
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http://dx.doi.org/10.3390/ijms22031216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7865252PMC
January 2021

CMV-specific Cell-Mediated Immunity Predicts High level of CMV Replication after Prophylaxis withdrawal in Lung Transplant Recipients.

J Infect Dis 2020 Nov 27. Epub 2020 Nov 27.

Experimental Nephrology and Transplantation Laboratory, IDIBELL, Barcelona, Spain.

Monitoring CMV-specific Cell-mediated immunity (CMV-CMI) has been shown to be useful predicting late-onset CMV infection in different solid organ transplants, but few data has been reported after Lung Transplantation (LT). CMV-CMI against two major CMV antigens (IE-1, pp65) was evaluated in 60 seropositive LT at 6-month prophylaxis withdrawal. LT with late-onset CMV infection showed significantly lower (IE-1)CMV-CMI than patients who did not (p=0.045), being more evident in patients developing high viral loads (p=0.010). Notably, (IE-1)CMV-CMI independently predicted high first late-onset viral replication (OR 4.358, 1.043-18.215).CMV-specific CMI may be a useful new immune tool guiding CMV preventive strategies after LT.
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http://dx.doi.org/10.1093/infdis/jiaa727DOI Listing
November 2020

Peripheral Blood RNA Sequencing Unravels a Differential Signature of Coding and Noncoding Genes by Types of Kidney Allograft Rejection.

Kidney Int Rep 2020 Oct 26;5(10):1706-1721. Epub 2020 Jul 26.

Division of Transplant Surgery, University of California San Francisco, San Francisco, California, USA.

Introduction: Peripheral blood (PB) molecular patterns characterizing the different effector immune pathways driving distinct kidney rejection types remain to be fully elucidated. We hypothesized that transcriptome analysis using RNA sequencing (RNAseq) in samples of kidney transplant patients would enable the identification of unique protein-coding and noncoding genes that may be able to segregate different rejection phenotypes.

Methods: We evaluated 37 biopsy-paired PB samples from the discovery cohort, with stable (STA), antibody-mediated rejection (AMR), and T cell-mediated rejection (TCMR) by RNAseq. Advanced machine learning tools were used to perform 3-way differential gene expression analysis to identify gene signatures associated with rejection. We then performed functional in silico analysis and validation by Fluidigm (San Francisco, CA) in 62 samples from 2 independent kidney transplant cohorts.

Results: We found 102 genes (63 coding genes and 39 noncoding genes) associated with AMR (54 upregulated), TCMR (23 upregulated), and STA (25 upregulated) perfectly clustered with each rejection phenotype and highly correlated with main histologic lesions (ρ = 0.91). For the genes associated with AMR, we found enrichment in regulation of endoplasmic reticulum stress, adaptive immunity, and Ig class-switching. In the validation, we found that the pseudogene and 9 -related coding genes were highly expressed among AMR but not in TCMR and STA samples.

Conclusions: This analysis identifies a critical gene signature in PB in kidney transplant patients undergoing AMR, sufficient to differentiate them from patients with TCMR and immunologically quiescent kidney allografts. Our findings provide the basis for new studies dissecting the role of noncoding genes in the pathophysiology of kidney allograft rejection and their potential value as noninvasive biomarkers of the rejection process.
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http://dx.doi.org/10.1016/j.ekir.2020.07.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7569686PMC
October 2020

Functional immune monitoring of BK Virus and donor-specific T-cell effector immune responses to guide treatment decision-making after kidney transplantation; an illustrative case report and literature review.

Transpl Infect Dis 2021 Apr 3;23(2):e13495. Epub 2020 Nov 3.

Kidney Transplant Unit, Nephrology Department, Bellvitge University Hospital, University of Barcelona, Barcelona, Spain.

Differential diagnosis between Polyoma virus associated-nephropathy (PVAN) and T-cell mediated rejection (TCMR) might be challenging, as respective treatment approaches are totally opposite. Here we report the illustrative case of a kidney transplant recipient with PVAN who developed a persistent acute TCMR after full abrogation of viral infection through immunosuppression modulation. By simultaneous functional immune monitoring of BKV and donor-specific T-cell responses using IFN-γELISPOT assay, we retrospectively demonstrated the predominant effector mechanisms responsible of allograft injury and thus, potential guidance for treatment decision-making. Furthermore, the evidence of an efficient T-cell alloimmunity abrogation accompanied by a sustained anti-viral response after sirolimus addition, promotes the potential benefit of converting patients to an mTOR-based immunosuppression in case of PVAN.
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http://dx.doi.org/10.1111/tid.13495DOI Listing
April 2021

Impact of donor extracellular vesicle release on recipient cell "cross-dressing" following clinical liver and kidney transplantation.

Am J Transplant 2020 Jun 9. Epub 2020 Jun 9.

Medical Research Council (MRC) Centre for Transplantation, Institute of Liver Studies, King's College London, London, United Kingdom.

In several murine models of transplantation, the "cross-dressing" of recipient antigen presenting cells (APCs) with intact donor major histocompatibility complex (MHC) derived from allograft-released small extracellular vesicles (sEVs) has been recently described as a key mechanism in eliciting and sustaining alloimmune responses. Investigation of these processes in clinical organ transplantation has, however, been hampered by the lack of sensitivity of conventional instruments and assays. We have employed advanced imaging flow cytometry (iFCM) to explore the kinetics of allograft sEV release and the extent to which donor sEVs might induce cross-dressing following liver and kidney transplantation. We report for the first time that recipient APC cross-dressing can be transiently detected in the circulation shortly after liver, but not kidney, transplantation in association with the release of HLA-bearing allograft-derived sEVs. In liver transplant recipients the majority of circulating cells exhibiting donor HLA are indeed cross-dressed cells and not passenger leukocytes. In keeping with experimental animal data, the downstream functional consequences of the transfer of circulating sEVs harvested from human transplant recipients varies depending on the type of transplant and time posttransplant. sEVs released shortly after liver, but not kidney, transplantation exhibit immunoinhibitory effects that could influence liver allograft immunogenicity.
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http://dx.doi.org/10.1111/ajt.16123DOI Listing
June 2020

Cellular Immunity to Predict the Risk of Cytomegalovirus Infection in Kidney Transplantation: A Prospective, Interventional, Multicenter Clinical Trial.

Clin Infect Dis 2020 12;71(9):2375-2385

Experimental Nephrology Laboratory, Bellvitge Biomedical Research Institute, IDIBELL, Hospitalet de Llobregat, Spain.

Background: Improving cytomegalovirus (CMV) immune-risk stratification in kidney transplantation is highly needed to establish guided preventive strategies.

Methods: This prospective, interventional, multicenter clinical trial assessed the value of monitoring pretransplant CMV-specific cell-mediated immunity (CMI) using an interferon-γ release assay to predict CMV infection in kidney transplantation. One hundred sixty donor/recipient CMV-seropositive (D+/R+) patients, stratified by their baseline CMV (immediate-early protein 1)-specific CMI risk, were randomized to receive either preemptive or 3-month antiviral prophylaxis. Also, 15-day posttransplant CMI risk stratification and CMI specific to the 65 kDa phosphoprotein (pp65) CMV antigen were investigated. Immunosuppression consisted of basiliximab, tacrolimus, mycophenolate mofetil, and corticosteroids in 80% of patients, whereas 20% received thymoglobulin induction therapy.

Results: Patients at high risk for CMV based on pretransplant CMI developed significantly higher CMV infection rates than those deemed to be at low risk with both preemptive (73.3% vs 44.4%; odds ratio [OR], 3.44 [95% confidence interval {CI}, 1.30-9.08]) and prophylaxis (33.3% vs 4.1%; OR, 11.75 [95% CI, 2.31-59.71]) approaches. The predictive capacity for CMV-specific CMI was only found in basiliximab-treated patients for both preemptive and prophylaxis therapy. Fifteen-day CMI risk stratification better predicted CMV infection (81.3% vs 9.1%; OR, 43.33 [95% CI, 7.89-237.96]).

Conclusions: Pretransplant CMV-specific CMI identifies D+/R+ kidney recipients at high risk of developing CMV infection if not receiving T-cell-depleting antibodies. Monitoring CMV-specific CMI soon after transplantation further defines the CMV infection prediction risk. Monitoring CMV-specific CMI may guide decision making regarding the type of CMV preventive strategy in kidney transplantation.

Clinical Trials Registration: NCT02550639.
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http://dx.doi.org/10.1093/cid/ciz1209DOI Listing
December 2020

Novel insights into the pathobiology of humoral alloimmune memory in kidney transplantation.

Curr Opin Organ Transplant 2020 02;25(1):15-21

Experimental Nephrology and Transplantation Laboratory, IDIBELL.

Purpose Of Review: Humoral alloimmunity against human leukocyte antigen (HLA) antigens is the main barrier for successful transplantation. Recent researches have shown that this complex effector immune mechanism is driven by a number of B-cell subsets, which can orchestrate in a perfect and synergistic multistep manner the rejection of the organ transplant. Herein, our purpose is to review the immunobiology of humoral response and discuss novel therapeutic strategies derived from this evidence.

Recent Findings: Among the distinct cellular components of the humoral alloimmune system, memory B cells (mBC) have been shown to play a key role initiating and maintaining the antidonor humoral alloimmune response, thus its assessment apart from monitoring donor (HLA)-specific antibodies (DSA) in the sera may improve the understanding of the alloimmune status of transplant patients at different time points. Furthermore, targeting alloreactive mBC as well as other B and T-cell counterparts have highlighted for the first time, that novel therapeutic strategies with a more mechanistic rationale are highly warranted for achieving an effective anti-HLA humoral alloimmune control, also in human kidney transplantation.

Summary: The complex mechanisms of humoral allorecognitition in transplantation seem to be progressively better understood with the implementation of novel immune technologies. This new insight should serve for the development of novel immunosuppressive strategies to achieve an optimal humoral alloimmune regulation.
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http://dx.doi.org/10.1097/MOT.0000000000000717DOI Listing
February 2020

Pretransplant Donor-specific IFNγ ELISPOT as a Predictor of Graft Rejection: A Diagnostic Test Accuracy Meta-analysis.

Transplant Direct 2019 May 25;5(5):e451. Epub 2019 Apr 25.

Nephrology Department, Kidney transplant Unit, Bellvitge University Hospital, Barcelona, Spain.

Background: Pretransplant interferon-γ enzyme-linked immunospot (IFN-γ ELISPOT) has been proposed as a tool to quantify alloreactive memory T cells and estimate the risk of acute rejection (AR) after kidney transplantation, but studies have been inconclusive so far. We performed a meta-analysis to evaluate the association between pretransplant IFN-γ ELISPOT and AR and assess its predictive accuracy at the individual level.

Methods: We estimated the pooled summary of odds ratio for AR and the joined sensitivity and specificity for predicting AR using random-effects and hierarchical summary receiver-operating characteristic models. We used meta-regression models with the Monte Carlo permutation method to adjust for multiple tests to explain sensitivity and specificity heterogeneity across studies. The meta-analytic estimates of sensitivity and specificity were used to calculate positive and negative predictive values across studies.

Results: The analysis included 12 studies and 1181 patients. IFN-γ ELISPOT was significantly associated with increased AR risk (odds ratio: 3.29; 95% confidence interval (CI), 2.34-4.60); hierarchical summary receiver operating characteristic jointly estimated sensitivity and specificity values were 64.9% (95% CI, 53.7%-74.6%) and 65.8% (95% CI, 57.4%-73.5%), respectively, with moderate heterogeneity across studies. After adjusting for multiple testing, meta-regression models showed that thymoglobulin induction, recipient black ethnicity, living versus deceased donors, and geographical location did not affect sensitivity or specificity. Because of the varying AR incidence of the studies, positive and negative predictive values ranged between 16%-60% and 70%-95%, respectively.

Conclusions: Pretransplant IFN-γ ELISPOT is significantly associated with increased risk of AR but provides suboptimal predictive ability at an individual level. Prospective randomized clinical trials are warranted.
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http://dx.doi.org/10.1097/TXD.0000000000000886DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6511445PMC
May 2019

Different impact of rATG induction on CMV infection risk in D+R- and R+ KTRs.

J Infect Dis 2019 07;220(5):761-771

Department of Nephrology, Transplantation, Dialysis and Apheresis, Pellegrin University Hospital, Bordeaux, France.

Background: Rabbit antithymocyte globulin (rATG) induction is associated with profound immunosuppression, leading to a higher risk of cytomegalovirus (CMV) infection compared with anti-interleukin 2 receptor antibody (anti-IL-2RA). However, this risk, depending on the baseline CMV serological recipient/donor status, is still controversial.

Methods: The CMV DNAemia-free survival between rATG- and anti-IL-2RA-treated patients was analyzed in donor-positive/recipient-negative (D+R-) and recipient-positive (R+) patients in 1 discovery cohort of 559 kidney transplant recipients (KTRs) and 2 independent cohorts (351 and 135 kidney KTRs). The CMV-specific cell-mediated immunity (CMI) at baseline and at different time points after transplantation was assessed using an interferon γ enzyme-linked immunosorbent spot assay.

Results: rATG increased the risk of CMV DNAemia in R+ but not in D+R- KTRs. In R+ CMI-positive (CMI+) patients, the CMV DNAemia rate was higher in rATG-treated than in anti-IL-2RA-treated patients; no difference was observed among R+ CMI-negative (CMI-) patients. Longitudinal follow-up demonstrated a deeper depletion of preformed CMV CMI in R+ rATG-treated patients.

Conclusions: D+R- KTRs have the highest risk of CMV DNAemia, but rATG adds no further risk. Among R+ KTRs, we described 3 groups, the least prone being R+CMI+ KTRs without rATG, then R+CMI+ KTRs with rATG, and finally R+CMI- KTRs. CMV serostatus, baseline CMV-specific CMI, and induction therapy may lead to personalized preventive therapy in further studies.
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http://dx.doi.org/10.1093/infdis/jiz194DOI Listing
July 2019

First description of sarcoptic mange in the endangered Iberian lynx (): clinical and epidemiological features.

Eur J Wildl Res 2019 24;65(3):40. Epub 2019 Apr 24.

Centro de Recuperación de Fauna Silvestre "El Chaparrillo"; GEACAM, JCCM, Ciudad Real, Spain.

A 6-month-old female Iberian lynx () cub that was severely affected by mange died in September 2016 in the Montes de Toledo (Spain) with crusts and fissures on its face, outer ears, nipples and footpads. The body condition of the cub was very poor, and it also had a mandibular abscess and a severely ankylosed luxation on its left knee. After confirming that the origin of the deceased cub's dermal lesions was , the subsequent search for ectoparasites and a comparison of histopathological and immunohistochemical findings in all sympatric lynxes handled ( = 30) and submitted for necropsy ( = 4) during 2016 and 2017 revealed the presence of mites and/or milder mange compatible lesions in five members of her family group, which was treated against mange together with two exposed contiguous family groups. An ELISA developed by the authors showed the presence of antibodies against in the deceased female cub and one brother. The presence of concomitant immunosuppressive factors in the dead female cub and the results obtained for the other sympatric lynxes studied since 2016 suggest that had a limited effect on immune-competent Iberian lynxes in the local population of the Montes de Toledo. However, a different evolution and relevance of sarcoptic mange in different populations-or even in the same one in the presence of immunosuppressive factors-cannot be ruled out, thus confirming the need for further research in order to attain a complete comprehension of the epidemiology and the real threat that this ectoparasitic disease may imply for
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http://dx.doi.org/10.1007/s10344-019-1283-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7087905PMC
April 2019

The Presence of Urinary Renal Progenitor Cells in Stable Kidney Transplant Recipients Anticipates Allograft Deterioration.

Front Physiol 2018 10;9:1412. Epub 2018 Oct 10.

Nephrology Department, L'Hospitalet de Llobregat, Hospital Universitari de Bellvitge, Barcelona, Spain.

Long-term kidney transplant outcomes have reached mild improvements recently. Parietal epithelial cells (PECs) are progenitor cells located along the Bowman's capsule that can be isolated in urine, and display the capability to replace podocytes, but in certain situations cause glomerulosclerosis. In this study, a cohort of stable kidney transplant recipients with 6 months protocol biopsy was divided in two groups depending on the presence (uPEC+; = 41) or absence (uPEC-; = 25) of PECs in urine and followed for 2 years. No differences were found between groups at 6 months after transplantation considering clinical variables, alloimmune response, renal function, albuminuria and graft pathology. However, uPEC+ group showed increased podocyturia and a higher rate of proliferating PECs along the Bowman's capsule, without concomitant enhancement of the CD44 pro-sclerotic activation marker. Accordingly, 2 years follow up evidenced poorer outcomes in the uPEC+ group with worse renal function, increased albuminuria, wider mesangial expansion and more severe IFTA. In summary, chronic allograft damage can progress in certain stable-supposed grafts by podocyte detachment and reactive PECs proliferation, being the uPEC presence a biomarker of this process. This damage-response regenerative process, if sustained in time, might fail in preserve the allograft function and histology. Our study raises new prospects to overcome current limits on long-term allograft results.
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http://dx.doi.org/10.3389/fphys.2018.01412DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6191504PMC
October 2018

CMV-specific Cell-mediated Immunity at 3-month Prophylaxis Withdrawal Discriminates D+/R+ Kidney Transplants at Risk of Late-onset CMV Infection Regardless the Type of Induction Therapy.

Transplantation 2018 Nov;102(11):e472-e480

Experimental Nephrology Laboratory, IDIBELL, Barcelona, Spain.

Background: Whether cytomegalovirus (CMV)-specific cell-mediated immunity (CMI) at prophylaxis cessation predicts D+/R+ kidney transplants at risk of late-onset CMV infection after receiving distinct induction therapies is still not well characterized.

Methods: We prospectively assessed CMV-specific CMI predicting late-onset CMV infection at prophylaxis withdrawal and at earlier time-points, in 96 consecutive D+/R+ patients receiving either anti-interleukin 2-receptor antibody (anti-IL2RA; n = 50) or rabbit antithymoglobulin (n = 46). CMV-specific CMI was evaluated against CMV antigens (IE-1, pp65) using an IFN-γ ELISpot assay.

Results: Fourteen (14.6%) of 96 patients developed late-onset CMV infection and 2 (2.1%) of 96 displayed disease. At 3 months, CMV-specific CMI frequencies were significantly lower in patients developing late-onset CMV infection (P < 0.001 for IE-1, P = 0.030 for pp65), regardless the type of induction therapy. Receiver operating characteristic curve analyses showed accurate CMV-specific CMI cutoffs (25 and 130 IFN-γ spots for IE-1 and pp65, respectively) classifying patients into high risk, intermediate risk, or low risk (log-rank = 0.006; hazard ratio, 4.084; 95% confidence interval, 1.431-11.651; P = 0.009), being IE-1 CMI the strongest predictor (odds ratio, 5.554; 95% confidence interval, 1.486-20.766; P = 0.011). Although the profound posttransplant CMV-specific CMI inhibition among rabbit antithymocyte globulin-treated patients precludes its use for risk stratification both before and early after kidney transplant, a similar proportion of at-risk patients could be identified before month 3 within anti-interleukin 2-receptor antibody-treated patients.

Conclusions: Monitoring CMV-specific CMI at 3-month prophylaxis cessation discriminates kidney transplant recipient at risk of late-onset CMV infection, regardless the type of induction therapy.
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http://dx.doi.org/10.1097/TP.0000000000002421DOI Listing
November 2018

Value of monitoring circulating donor-reactive memory B cells to characterize antibody-mediated rejection after kidney transplantation.

Am J Transplant 2019 02 17;19(2):368-380. Epub 2018 Sep 17.

Experimental Nephrology Laboratory, IDIBELL, Barcelona, Spain.

Antibody-mediated rejection (ABMR) is defined by specific histopathological lesions and evidence of circulating donor-specific antibodies (DSA). Although DSA are not always detectable, monitoring donor-reactive memory B cells (mBC) could identify patients at risk of developing ABMR. Peripheral donor-reactive mBC using a novel HLA B cell ELISpot assay, serum DSA, and numbers of different B cell subsets were assessed in 175 consecutive kidney transplants undergoing either for-cause or 6- and 24-month surveillance biopsies for their association with main histological lesions of ABMR and impact on allograft outcome. In 85 incident for-cause biopsies, high frequencies of donor-reactive mBC were detected in all 16 (100%) acute ABMR/DSA+ and most chronic ABMR, with or without DSA (24/30[80%] and 21/29[72.4%], respectively). In a longitudinal cohort of 90 nonsensitized patients, a progressively higher expansion of donor-reactive mBC than de novo DSA was observed at 6 and 24 months (8.8% vs 7.7% and 15.5% vs 11.1%, respectively) and accurately identified patients with ongoing subclinical ABMR (area under the curve = 0.917 and area under the curve = 0.809, respectively). An unsupervised hierarchical cluster analysis revealed a strong association between donor-reactive mBC with main fundamental allograft lesions associated with ABMR and conferred a significant deleterious impact on graft outcome. Monitoring donor-reactive mBC may be useful to further characterize humoral rejection after kidney transplantation.
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http://dx.doi.org/10.1111/ajt.15055DOI Listing
February 2019

A multicolour HLA-specific B-cell FluoroSpot assay to functionally track circulating HLA-specific memory B cells.

J Immunol Methods 2018 11 31;462:23-33. Epub 2018 Jul 31.

Experimental Nephrology Laboratory, IDIBELL, Barcelona, Spain; Kidney Transplant Unit, Nephrology Department, Bellvitge University Hospital, Barcelona University, Barcelona, Spain. Electronic address:

Emerging evidence suggests that donor-reactive memory B cells (mBC) play a key role inducing antibody-mediated rejection (ABMR) after solid organ transplantation and show a broader antigen repertoire than plasma cells thus, being potentially present even in absence of donor-specific antibodies. Therefore, the development of novel immune assays capable of quantifying circulating donor-reactive mBC in organ transplantation is highly warranted. We developed a novel HLA-specific B-cell FluoroSpot assay capable of enumerating multiple HLA-specific Antibody Secreting Cells (ASC) originated from circulating mBC after in-vitro polyclonal activation. We performed a thorough characterization of distinct selective in-vitro mBC activation methods based on either the TLR7,8 agonist R848 plus Interleukin-2 or an anti-CD40 agonist monoclonal antibody, assessed optimal activation culture conditions, cell sources, activation time-frame as well as the advantage of measuring HLA-specific IgG-ASC as compared to HLA-IgG Ab detected in supernatants of in-vitro stimulated B-cell to characterize anti-HLA alloreactivity. Notably, using fluorescently-labeled multimerized HLA molecules as detection matrix, we show the ability of this assay to precisely quantify multiple anti-HLA mBC specificities. In conclusion, evaluating circulating donor-reactive mBC using new technology may provide novel insight of the pathogenesis of humoral rejection and may help identifying transplant recipients at high risk of allograft rejection.
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http://dx.doi.org/10.1016/j.jim.2018.07.011DOI Listing
November 2018

Impact of preformed T-cell alloreactivity by means of donor-specific and panel of reactive T cells (PRT) ELISPOT in kidney transplantation.

PLoS One 2018 30;13(7):e0200696. Epub 2018 Jul 30.

Experimental Nephrology Laboratory, IDIBELL, Barcelona University, Barcelona, Spain.

Donor-specific (d-sp) interferon gamma enzyme-linked immunosorbent spot (d-sp ELISPOT) and Panel of reactive T-cell (PRT) ELISPOT assays have been developed to detect alloreactive memory T (Tmem) cells in order to estimate the risk of acute rejection after kidney transplantation. Adding IL15 to the PRT assay (PRT+IL15) may uncover the presence of pathogenic alloreactive CD28-Tmem. Face-to-face comparisons of these assays have not been done yet. We performed pre-transplant d-sp ELISPOT and PRT assays (±IL15, against six B-cell lines) in 168 consecutive kidney transplant recipients and evaluated the multivariable-adjusted associations with biopsy-proven acute rejection (BPAR), de novo donor-specific antibodies (DSA), and eGFR decline over a 48-month follow-up period. D-sp ELISPOT was positive in 81 (48%) subjects, while 71 (42%) and 81 (48%) subjects displayed positive PRT and PRT+IL15, respectively. Their median [interquartile range] numerical test result was 23 [6-65], 18 [8-37], and 26 [10-45] spots/3x105 PBMCs, respectively. The number of PRT spots were weakly correlated with those of d-sp ELISPOT, but highly correlated with PRT+IL15 (rho = 0.96, P<0.001). d-sp ELISPOT, but not PRT (±IL15) was independently associated with BPAR (adjusted Odds Ratio of BPAR associated with d-sp ELISPOT positivity: 4.20 [95%CI: 1.06 to 21.73; P = 0.041]). Unlike d-sp ELISPOT, median PRT and PRT+IL15 were independently associated with higher Δ3-48month eGFR decline post-transplantation (for both assays, about -3mL/min/1.73m2 per one standard deviation unit increase in the spot number). Pre-transplant T-cell immune-monitoring using d-sp ELISPOT and PRT assays identifies kidney transplant candidates at high risk of BPAR and worse kidney allograft progression.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0200696PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6066206PMC
January 2019

Effector Antitumor and Regulatory T Cell Responses Influence the Development of Nonmelanoma Skin Cancer in Kidney Transplant Patients.

Transplantation 2017 09;101(9):2102-2110

1 Experimental Nephrology Laboratory, IDIBELL, Barcelona, Spain. 2 Renal Transplant Unit, Nephrology Department, Germans Trias i Pujol University Hospital, Barcelona, Spain. 3 Kidney Transplant Unit, Nephrology Department, Bellvitge University Hospital, IDIBELL, Barcelona, Spain. 4 Pathology Department, Bellvitge University Hospital, IDIBELL, Barcelona, Spain. 5 Pathology Department, Germans Trias i Pujol University Hospital, Barcelona, Spain.

Background: Chronic immunosuppression promotes nonmelanocytic squamous cell carcinoma (SCC) after kidney transplantation. Adaptive and innate immunity play a key role controlling tumor growth and are influenced by different immunosuppressive agents. We hypothesized that functional impairment of tumor-specific T cell responses due to calcineurin inhibitors (CNI) could contribute to SCC development, whereas conversion to mammalian target of rapamycin inhibitors (mTOR-i) could recover this protective immune response.

Methods: Peripheral tumor-specific T cell responses against main SCC-derived antigens using the IFN-γ enzyme-linked immunospot assay and intratumor (IT) and circulating immune phenotypes (CD4 + T, CD8 + T, CD20 + B, CD56 + NK, FOXP3 + regulatory T [Treg] cells) were explored in a cross-sectional analysis in 59 kidney transplant patients with SCC on CNI (KT-CNI-SCC) or mTOR-i (KT-mTORi-SCC), 25 nontransplants developing SCC (NoKT-SCC) and 6 healthy controls. Moreover, 25 KT-CNI-SCC were switched to mTOR-i and evaluated after 12 months.

Results: Kidney transplant patients showed lower IT infiltrates and tumor-specific T cell responses than NoKT-SCC, and intratumoral and circulating FOXP3 + Treg cells were higher in KT-mTORi-SCC (P < 0.05). Tumor-specific T cell responses were significantly lower in KT-CNI-SCC than KT-mTORi-SCC and NoKT-SCC and predicted SCC relapses (area under the curve = 0.837; P < 0.05). One-year after mTOR-i conversion, a significant increase in FOXP3 + Treg cell numbers and tumor-specific T cell responses were observed, reaching similar levels than KT-mTORi-SCC and NoKT-SCC patients.

Conclusions: Tumor-specific T cell responses are strongly impaired in CNI-treated patients but recover after mTOR-i conversion, reducing SCC relapses.
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http://dx.doi.org/10.1097/TP.0000000000001759DOI Listing
September 2017

Posttransplant peripheral blood donor-specific interferon-γ enzyme-linked immune spot assay differentiates risk of subclinical rejection and de novo donor-specific alloantibodies in kidney transplant recipients.

Kidney Int 2017 07 6;92(1):201-213. Epub 2017 Mar 6.

Experimental Nephrology Laboratory, IDIBELL, Barcelona University, Barcelona, Spain; Kidney Transplant Unit, Nephrology Department, Bellvitge University Hospital, Barcelona, Spain. Electronic address:

Noninvasive diagnosis of kidney allograft inflammation in transplant recipients with stable graft function (subclinical rejection) could permit more effective therapy and prevent later development of de novo anti-donor HLA antibodies and/or graft dysfunction. Here we tested whether quantifying posttransplant donor-specific alloreactive T-cells by IFN-γ ELISPOT assay noninvasively detects subclinical T-cell mediated rejection and/or predicts development of anti-donor HLA antibodies. Using an initial cross-sectional cohort of 60 kidney transplant patients with six-month surveillance biopsies, we found that negative donor-specific IFN-γ ELISPOT assays accurately ruled out the presence of subclinical T-cell mediated rejection. These results were validated using a distinct prospective cohort of 101 patients where donor-specific IFN-γ ELISPOT results at both three- and six-months posttransplant significantly differentiated patients with subclinical T-cell mediated rejection at six months, independent of other clinical variables (odds ratio 0.072, 95% confidence interval 0.008-0.653). The posttransplant donor-specific IFN-γ ELISPOT results independently associated with subsequent development of significant anti-donor HLA antibodies (0.085, 0.008-0.862) and with significantly worse two-year function (estimated glomerular filtration rate) compared to patients with a negative test. Thus, posttransplant immune monitoring by donor-specific IFN-γ ELISPOT can assess risk for developing subclinical T-cell mediated rejection and anti-donor HLA antibodies, potentially limiting the need for surveillance biopsies. Our study provides a guide for individualizing immunosuppression to improve posttransplant outcomes.
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http://dx.doi.org/10.1016/j.kint.2016.12.024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5930006PMC
July 2017

Molecular and Functional Noninvasive Immune Monitoring in the ESCAPE Study for Prediction of Subclinical Renal Allograft Rejection.

Transplantation 2017 06;101(6):1400-1409

1 Laboratory of Nephrology, IDIBELL, Barcelona, Spain. 2 Division of Transplant Surgery, University of California, San Francisco, San Francisco, CA. 3 Kidney Transplant Unit, Bellvitge University Hospital, IDIBELL, UB, Barcelona, Spain.

Background: Subclinical acute rejection (sc-AR) is a main cause for functional decline and kidney graft loss and may only be assessed through surveillance biopsies.

Methods: The predictive capacity of 2 novel noninvasive blood biomarkers, the transcriptional kidney Solid Organ Response Test (kSORT), and the IFN-γ enzyme-linked immunosorbent spot assay (ELISPOT) assay were assessed in the Evaluation of Sub-Clinical Acute rejection PrEdiction (ESCAPE) Study in 75 consecutive kidney transplants who received 6-month protocol biopsies. Both assays were run individually and in combination to optimize the use of these techniques to predict sc-AR risk.

Results: Subclinical acute rejection was observed in 22 (29.3%) patients (17 T cell-mediated subclinical rejection [sc-TCMR], 5 antibody-mediated subclinical rejection [sc-ABMR]), whereas 53 (70.7%) showed a noninjured, preserved (stable [STA]) parenchyma. High-risk (HR), low-risk, and indeterminate-risk kSORT scores were observed in 15 (20%), 50 (66.7%), and 10 (13.3%) patients, respectively. The ELISPOT assay was positive in 31 (41%) and negative in 44 (58.7%) patients. The kSORT assay showed high accuracy predicting sc-AR (specificity, 98%; positive predictive value 93%) (all sc-ABMR and 58% sc-TCMR showed HR-kSORT), whereas the ELISPOT showed high precision ruling out sc-TCMR (specificity = 70%, negative predictive value = 92.5%), but could not predict sc-ABMR, unlike kSORT. The predictive probabilities for sc-AR, sc-TCMR, and sc-ABMR were significantly higher when combining both biomarkers (area under the curve > 0.85, P < 0.001) and independently predicted the risk of 6-month sc-AR in a multivariate regression analysis.

Conclusions: Combining a molecular and immune cell functional assay may help to identify HR patients for sc-AR, distinguishing between different driving alloimmune effector mechanisms.
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http://dx.doi.org/10.1097/TP.0000000000001287DOI Listing
June 2017

Biomarkers to assess donor-reactive T-cell responses in kidney transplant patients.

Clin Biochem 2016 Mar 14;49(4-5):329-37. Epub 2015 Aug 14.

Laboratory of Experimental Nephrology, IDIBELL, Barcelona, Spain; Kidney Transplant Unit, Nephrology Department, Bellvitge University Hospital, Barcelona University, Barcelona, Spain. Electronic address:

Different to antibody-mediated rejection (ABMR), T-cell mediated rejection (TCMR) still unpredictably occurs after kidney transplantation in a great part because of a poor immunologic evaluation of the cellular allogeneic immune response. However, in the last years, important efforts have focused on the development of novel and more sensitive assays to monitor T-cell alloimmune responses at different biological levels that may improve the understanding of the functional status of the cellular immune compartment in patients undergoing organ transplantation. In this direction, immune assays evaluating T-cell proliferation, intracellular ATP release, multiparameter flow cytometry, profiling T-cell receptor repertoires and measurements of frequencies of cytokine-producing T-cells using an IFN-γ enzyme-linked immunospot assay (IFN-γ ELISPOT) have been reported showing interesting associations between the cellular alloimmune response and kidney transplant outcomes. In summary, an important progress has been made in the assessment of alloreactive T-cell responses in the context of organ transplantation using novel immune assays at different biological levels. However, there is an urgent need for prospective, randomized clinical studies to validate these encouraging preliminary data to ultimately introduce them in current clinical practice for refining current immune-risk stratification in kidney transplantation.
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http://dx.doi.org/10.1016/j.clinbiochem.2015.08.010DOI Listing
March 2016

Preformed circulating HLA-specific memory B cells predict high risk of humoral rejection in kidney transplantation.

Kidney Int 2015 Oct 15;88(4):874-87. Epub 2015 Jul 15.

Experimental Nephrology Laboratory, IDIBELL, Barcelona, Spain.

The accurate evaluation of donor-specific antibodies (DSAs) has allowed a precise identification of sensitized patients at risk of antibody-mediated rejection (ABMR). However, the scale of the humoral response is not always fully addressed, as it excludes the complete memory B-cell (mBC) pool such as that caused by antigen-specific mBC. Using a novel B-cell ELISpot assay approach, we assessed circulating mBC frequencies against class I and II HLA antigens in highly sensitized and nonsensitized patients in the waiting list for kidney transplantation. Also, kidney transplant patients undergoing ABMR were evaluated for the presence of donor-specific mBCs both at the time of rejection and before transplantation. For this purpose, 278 target HLA-sp antigens from 70 patients were studied and compared to circulating HLA-sp antibodies. Both class I and II HLA-sp mBC frequencies were identified in highly sensitized individuals but not in nonsensitized and healthy individuals, many years after first sensitization. Also, high donor-specific mBC responses were clearly found both during ABMR and before transplantation, regardless of circulating DSA. The higher the donor-specific mBC response, the more aggressive the allograft rejection. Thus, assessing donor-specific mBC frequencies may be relevant to better refine patient alloimmune-risk stratification, and provides new insight into the mechanisms of the adaptive humoral alloimmune response taking place in kidney transplantation.
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http://dx.doi.org/10.1038/ki.2015.205DOI Listing
October 2015

De novo use of a generic formulation of tacrolimus versus reference tacrolimus in kidney transplantation: evaluation of the clinical results, histology in protocol biopsies, and immunological monitoring.

Transpl Int 2015 Nov 14;28(11):1283-90. Epub 2015 Jul 14.

Bellvitge University Hospital, Department of Nephrology, Renal Transplantation Unit carrer de la feixa llarga L'Hospitalet de Llobregat, Barcelona, Spain.

The use of generic formulations of immunosuppressive drugs in renal transplantation has been and still is a controversial subject. The lack of clinical studies about safety and efficacy in transplant patients is one of the factors restricting the diffusion of generic drugs in the renal transplant field. Since March 2013, our transplant unit has incorporated generic tacrolimus (Adoport(®) ; Sandoz), replacing the one we were currently using (Prograf(®) ; Astellas). When carrying out our retrospective analysis comparing the two different formulations, we evaluated several clinical results: tacrolimus trough concentrations (C0) at 5-7 days; 1, 3, and 6 months post-transplantation; concentration/dose ratio at 6 months; acute rejection incidence; delayed graft function (DGF); renal function (as CKD-EPI); and proteinuria at 6 months in 120 patients (1:1 ratio of Prograf(®) versus Adoport(®) ), noticing no important differences. We also evaluated the results of protocol biopsies at 6 months in a subgroup of patients, thus verifying the safety and efficacy of this particular generic drug versus the reference product on a histological basis as well. No difference in the development of dnDSA (de novo donor-specific antibody) was found between the two groups.
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http://dx.doi.org/10.1111/tri.12626DOI Listing
November 2015

Factors related to NT-proBNP levels in HIV patients aged over 40 years.

AIDS Res Ther 2015 10;12:17. Epub 2015 May 10.

Internal Medicine Unit, Costa del Sol Hospital., 29603 Marbella, Spain.

Objective: To determine the levels of NT-pro BNP in HIV patients over 40 years who are receiving highly active antiretroviral therapy (HAART) and investigating potential independent clinical or laboratory factors.

Method: We determine levels of NT-pro BNP in peripheral blood of HIV patients from Costa del Sol Hospital, over 40 years. We collected epidemiological, classical cardiovascular risk factors and variables associated with HIV infection status. The qualitative variables were compared using the χ2 test. NT-proBNP levels were taken as the dependent variable. The association between these levels and the quantitative variables were studied by analysis of variance (ANOVA), and the association with the qualitative variables, using Student's t test.

Results: Nt-pro BNP levels were determined in 146 HIV patients. We assess the 10-year cardiovascular risk calculated by the Framingham equation, 59 (41.5%) were classified as low risk, 46 (32.4%) as a moderate risk and 37 (26.1%) as a high risk. The higher levels of NT-pro BNP were found in women, and in those patient with lower filtration rate and high levels of triglycerides. An association was also observed between higher levels of NT-proBNP and the recent use of lamivudine and fosamprenavir. After a multivariate analysis we found an association between higher levels of NT-proBNP and the current use of fosamprenavir and a lower glomerular filtration rate.

Conclusions: We found, with the limitations of a small serie, that higher levels of NTproBNP in HIV patients could be linked to the occurrence of cardiovascular events, this fact suggest that NTpro BNP could be used in patients at moderate or high vascular risk in order to optimise the primary prevention of vascular events.
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http://dx.doi.org/10.1186/s12981-015-0058-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4426165PMC
May 2015

Pre-transplant donor-specific T-cell alloreactivity is strongly associated with early acute cellular rejection in kidney transplant recipients not receiving T-cell depleting induction therapy.

PLoS One 2015 17;10(2):e0117618. Epub 2015 Feb 17.

Experimental Nephrology Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain; Renal Transplant Unit, Nephrology department, Bellvitge University Hospital, Barcelona, Spain.

Preformed T-cell immune-sensitization should most likely impact allograft outcome during the initial period after kidney transplantation, since donor-specific memory T-cells may rapidly recognize alloantigens and activate the effector immune response, which leads to allograft rejection. However, the precise time-frame in which acute rejection is fundamentally triggered by preformed donor-specific memory T cells rather than by de novo activated naïve T cells is still to be established. Here, preformed donor-specific alloreactive T-cell responses were evaluated using the IFN-γ ELISPOT assay in a large consecutive cohort of kidney transplant patients (n = 90), to assess the main clinical variables associated with cellular sensitization and its predominant time-frame impact on allograft outcome, and was further validated in an independent new set of kidney transplant recipients (n = 67). We found that most highly T-cell sensitized patients were elderly patients with particularly poor HLA class-I matching, without any clinically recognizable sensitizing events. While one-year incidence of all types of biopsy-proven acute rejection did not differ between T-cell alloreactive and non-alloreactive patients, Receiver Operating Characteristic curve analysis indicated the first two months after transplantation as the highest risk time period for acute cellular rejection associated with baseline T-cell sensitization. This effect was particularly evident in young and highly alloreactive individuals that did not receive T-cell depletion immunosuppression. Multivariate analysis confirmed preformed T-cell sensitization as an independent predictor of early acute cellular rejection. In summary, monitoring anti-donor T-cell sensitization before transplantation may help to identify patients at increased risk of acute cellular rejection, particularly in the early phases after kidney transplantation, and thus guide decision-making regarding the use of induction therapy.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0117618PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4331510PMC
January 2016

Preformed frequencies of cytomegalovirus (CMV)-specific memory T and B cells identify protected CMV-sensitized individuals among seronegative kidney transplant recipients.

Clin Infect Dis 2014 Dec 21;59(11):1537-45. Epub 2014 Jul 21.

Experimental Nephrology Laboratory, Bellvitge Biomedical Research Institute Renal Transplant Unit, Nephrology Department.

Background: Cytomegalovirus (CMV) infection remains a major complication after kidney transplantation. Baseline CMV risk is typically determined by the serological presence of preformed CMV-specific immunoglobulin (Ig) G antibodies, even though T-cell responses to major viral antigens are crucial when controlling viral replication. Some IgG-seronegative patients who receive an IgG-seropositive allograft do not develop CMV infection despite not receiving prophylaxis. We hypothesized that a more precise evaluation of pretransplant CMV-specific immune-sensitization using the B and T-cell enzyme-linked immunospot assays may identify CMV-sensitized individuals more accurately, regardless of serological evidence of CMV-specific IgG titers.

Methods: We compared the presence of preformed CMV-specific memory B and T cells in kidney transplant recipients between 43 CMV IgG-seronegative (sR(-)) and 86 CMV IgG-seropositive (sR(+)) patients. Clinical outcome was evaluated in both groups.

Results: All sR(+) patients showed a wide range of CMV-specific memory T- and B-cell responses. High memory T- and B-cell frequencies were also clearly detected in 30% of sR(-) patients, and those with high CMV-specific T-cell frequencies had a significantly lower incidence of late CMV infection after prophylactic therapy. Receiver operating characteristic curve analysis for predicting CMV viremia and disease showed a high area under the receiver operating characteristic curve (>0.8), which translated into a high sensitivity and negative predictive value of the test.

Conclusions: Assessment of CMV-specific memory T- and B-cell responses before kidney transplantation among sR(-) recipients may help identify immunized individuals more precisely, being ultimately at lower risk for CMV infection.
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http://dx.doi.org/10.1093/cid/ciu589DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4650765PMC
December 2014

ROI-scavenging enzyme activities as toxicity biomarkers in three species of marine microalgae exposed to model contaminants (copper, Irgarol and atrazine).

Ecotoxicol Environ Saf 2014 Jun 15;104:294-301. Epub 2014 Apr 15.

Instituto de Ciencias Marinas de Andalucía (CSIC). Campus Río San Pedro s/n, 11510 Puerto Real, Cádiz, Spain. Electronic address:

There is a need to develop efficient tools to prevent damage to marine ecosystems due to pollution. Since microalgae play a key role in marine ecosystems, they are considered potentially useful for quick and sensitive toxicity bioassays. In this study an integrative analysis has been carried out of the anti-oxidant enzyme activities of marine microalgae species. Three marine microalgae species (Cylindrotheca closterium, a benthic diatom; Phaeodactylum tricornutum, a diatom which has been used as model organism in toxicity bioassays; and Rhodomonas salina, a cryptophyceae which is considered to present a certain level of heterotrophy) were exposed to selected concentrations of three model pollutants: copper (5 and 10µg L(-1)), atrazine (25 and 50µg L(-1)) and Irgarol (0.5 and 1.0µg L(-1)). These pollutant concentrations are environmentally relevant for coastal ecosystems, and have been selected for checking the efficiency of the reactive oxygen intermediate (ROI) scavenging enzyme system of these organisms. Superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx) and glutathione peroxidase (GPx) activities were measured at the end of 24h exposure. The integrated biomarker response (IBR) index - in our case for oxidative stress - has been employed to evaluate the ROI-scavenging enzyme system for each species and each treatment. In general, the SOD and CAT enzyme activities measured were higher in exposed populations than in controls, whereas APx and GPx activities showed the opposite trend. These microalgae showed significant responses of oxidative stress biomarkers at environmentally relevant concentrations for the assayed pollutants and short exposure periods, conditions that most other model organisms cannot match. Therefore microalgae present clear advantages over other species for their prospective employment in an "early warning system".
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http://dx.doi.org/10.1016/j.ecoenv.2014.03.021DOI Listing
June 2014

Epiphyte toxicity bioassay for ecotoxicological and coastal monitoring.

Environ Monit Assess 2014 Aug 20;186(8):4647-54. Epub 2014 Mar 20.

Institute of Marine Sciences of Andalusia (CSIC), Campus Rio San Pedro, Puerto Real, 11510, Cadiz, Spain.

Marine epibionts are organisms that grow on submerged surfaces. Those found on seagrass leaves are especially important because of their interactions with the plants, their contribution to primary production in these ecosystems, and their role as food source for heterotrophic fauna. Given the relative lack of ecotoxicological studies on epibionts, the aim of this study is to evaluate the effect of environmental pollution on epiphytes experimentally attached to artificial devices (mimes) consisting of thermally-sealed silicone tubes supported on bamboo sticks that mimic the morphology of seagrasses and serve as an anchor surface for marine epibionts. Mimes were installed on the sea floor in subtidal waters of the Rio San Pedro (Cádiz), collected after 28 days, and incubated in the laboratory with environmental concentrations of atrazine (herbicide), Irgarol (anti-fouling substance), and copper. Tube-dwelling diatoms formed the major component of the epiphyte community. Average surface covering, chlorophyll, and biomass content did not show significant differences between controls and treatments. The glutathione peroxidase activity increased significantly with 4 μg L(-1) of atrazine and 5 μg L(-1) of copper. This enzymatic activity increase seems to be sufficient to prevent oxidative cellular damage by removing reactive oxygen substances produced by oxidative stress; in addition to this enzyme, there might be other antioxidant enzymes which have not been measured in this study, that have also protected the organism from oxidative damage. Thus, the measurement of antioxidant enzymatic activity in epiphytes may be a useful toxicity indicator for coastal biomonitoring.
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http://dx.doi.org/10.1007/s10661-014-3725-6DOI Listing
August 2014

Human CMV-specific T-cell responses in kidney transplantation; toward changing current risk-stratification paradigm.

Transpl Int 2014 Jul 12;27(7):643-56. Epub 2014 Apr 12.

Experimental Nephrology Laboratory, IDIBELL, Barcelona, Spain.

Despite the great efficacy of current antiviral preventive strategies, hCMV infection is still a major complication after renal transplantation, significantly challenging patient and graft survival. This issue seems to be explained because of the rather poor immunologic monitoring of the antiviral immune response. An important body of evidence has shown that monitoring the hCMV-specific T-cell response, at different time points of the transplant setting, seems to add crucial information for predicting the risk of viral infection, thus potentially helping individualization of therapeutic decision-making in clinical transplantation. While several immune-cellular assays have shown its capability for accurately monitoring hCMV-specific T-cell responses, only few such as the IFN-γ ELISPOT and the ELISA based technology assays might be reliable for its application in the clinic. Nonetheless, an important effort has to be made among the transplant community to standardize and validate such immune assays. Noteworthy, large-scale prospective randomized trials are highly warranted to ultimately introduce them in current clinical practice as a part of the highly desired personalized medicine.
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http://dx.doi.org/10.1111/tri.12318DOI Listing
July 2014