Publications by authors named "Jens Kjeldsen-Kragh"

51 Publications

Fetal and Neonatal Alloimmune Thrombocytopenia-New Prospects for Fetal Risk Assessment of HPA-1a-Negative Pregnant Women.

Transfus Med Rev 2020 10 16;34(4):270-276. Epub 2020 Sep 16.

Department of Clinical Immunology and Transfusion Medicine, University and Regional Laboratories, Region Skåne, Lund, Sweden.

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare and potentially serious bleeding condition in the fetus/newborn. FNAIT is usually considered as the platelet counterpart of hemolytic disease of the fetus and newborn. In FNAIT, maternal alloantibodies against paternally inherited platelet antigens traverse the placenta and cause thrombocytopenia in the fetus/newborn. The most common and most serious cases of FNAIT among white people are caused by alloantibodies against the human platelet antigen 1a (HPA-1a), which is absent in 2.3% of women. Today, there is no screening for FNAIT, and for this reason, FNAIT is not suspected until an otherwise healthy child, born at term, presents with thrombocytopenia. Clinical management of subsequent pregnancies at risk of FNAIT is mostly based on the obstetric history. During the last 5 decades, hemolytic disease of the fetus and newborn caused by antibodies against RhD has successfully been prevented by administration of hyperimmune anti-D IgG drug products to RhD-negative women after delivery of an RhD-positive child. Similarly, a hyperimmune anti-HPA-1a IgG (NAITgam) is under development for the prevention of HPA-1a immunization and FNAIT. If NAITgam becomes licensed for FNAIT prophylaxis and national health authorities decide to include FNAIT screening in their antenatal health care programs, it will be necessary to improve today's tools for assessing the risk of FNAIT. Although the primary risk factor for HPA-1a immunization is platelet type HPA-1bb, not all HPA-1a-negative women develop anti-HPA-1a. The women who are HLA-DRB3:01:01 negative (72%) only rarely develop anti-HPA-1a, and for those few who become HPA-1a immunized, it is quite rare to have a child with severe thrombocytopenia. Determination of fetal HPA-1 type is important because 15% of HPA-1a-negative women will carry an HPA-1a-negative fetus and therefore not be at risk of FNAIT. The severity of FNAIT seems to be associated with the level of anti-HPA-1a. Hence, in Norway, for example, an Ab threshold of 3 IU/mL is used to distinguish between low- and high-risk pregnancies. The current review will discuss to what extent these analyses, as well as determination of subtypes of anti-HPA-1a (anti-β3, anti-αIIbβ3, and anti-αvβ3) and Fc core fucosylation of anti-HPA-1a IgG, can be used as risk stratification tools.
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http://dx.doi.org/10.1016/j.tmrv.2020.09.004DOI Listing
October 2020

Fetal/neonatal alloimmune thrombocytopenia: a systematic review of impact of HLA-DRB3*01:01 on fetal/neonatal outcome.

Blood Adv 2020 07;4(14):3368-3377

Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.

The most common, severe cases of fetal and neonatal alloimmune thrombocytopenia among whites are caused by antibodies against human platelet antigen 1a (HPA-1a). The aims of this systematic review and meta-analysis are to determine the association between maternal HLA-DRB3*01:01 and: (1) HPA-1a-alloimmunization and (2) neonatal outcome in children born of HPA-1a-immunized women. A systematic literature search identified 4 prospective and 8 retrospective studies. Data were combined across studies to estimate pooled odds ratios (ORs) and the associated 95% confidence intervals (CIs). The population represented by the prospective studies was more than 150 000. In the prospective studies, there were 64 severely thrombocytopenic newborns (platelet count <50 × 109/L) of whom 3 had intracranial hemorrhage. The mothers of all 64 children were HLA-DRB3*01:01+. The number of severely thrombocytopenic children born of HPA-1a-alloimmunized women in the retrospective studies was 214; 205 of whom were born of HLA-DRB3*01:01+ women. For HLA-DRB3*01:01- women, the OR (95% CI) for alloimmunization was 0.05 (0.00-0.60), and for severe neonatal thrombocytopenia 0.08 (0.02-0.37). This meta-analysis demonstrates that the risk of alloimmunization and of having a child with severe thrombocytopenia are both very low for HPA-1a- women who are HLA-DRB3*01:01-.
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http://dx.doi.org/10.1182/bloodadvances.2020002137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7391152PMC
July 2020

A combined effect of anti-HPA-1a and anti-HLA Class I in pregnancy?

Transfusion 2020 09 30;60(9):2121-2129. Epub 2020 Jun 30.

Immunology Research Group, Institute of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway.

Background: Maternal anti-human leukocyte antigen (HLA) Class I is commonly detected alongside anti-human platelet antigen (HPA)-1a in fetal and neonatal alloimmune thrombocytopenia (FNAIT). Little is known regarding whether the presence of anti-HLA Class I may exert an additive effect on the risk and severity of FNAIT.

Methods And Materials: We reanalyzed samples originally collected as part of a large Norwegian screening study on FNAIT during 1995-2004. This study identified and managed 170 pregnancies where the mother was HPA-1a negative and had detectable anti-HPA-1a during pregnancy. Maternal samples from 166 of these pregnancies were rescreened for anti-HLA Class I, revealing 111 (67%) that were antibody positive. Various regression models were used to assess if and how maternal anti-HLA Class I influenced the neonatal platelet count.

Results And Conclusions: Unadjusted neonatal platelet counts and the frequency of neonatal thrombocytopenia was not significantly affected by the presence of anti-HLA Class I alongside anti-HPA-1a, but results from regression analyses revealed a possible increased risk when the mother was nulliparous. These results warrant further investigation.
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http://dx.doi.org/10.1111/trf.15944DOI Listing
September 2020

The prevalence of HPA-1a alloimmunization and the potential risk of FNAIT depend on both the DRB3*01:01 allele and associated DR-DQ haplotypes.

Scand J Immunol 2020 Jul 17;92(1):e12890. Epub 2020 May 17.

Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway.

Alloimmunization against human platelet antigen (HPA)-1a during pregnancy can cause foetal/neonatal alloimmune thrombocytopenia (FNAIT) and severe bleeding in the foetus or newborn and likely depends on several factors. HPA-1a alloimmunization is associated with DRB3*01:01, which is associated with several DR-DQ haplotypes. However, it is not known to what extent these haplotypes contribute to the prevalence of HPA-1a alloimmunization. HPA-1a-alloimmunized women, identified in a prospective study, and random donors were typed for selected DRB3, DRB4, DRB1, DQA1 and DQB1 alleles to determine allele and DR-DQ haplotype frequencies. DRB3*01:01 was carried by 94% HPA-1a-immunized women compared to 27% in the general population. In the first population, the DR3-DQ2 haplotype was overrepresented (P < .003). The prevalence of HPA-1a alloimmunization was estimated to be about twice as frequent with DR3-DQ2 compared to DR13-DQ6, together accounting for about 90% of DRB3*01:01-positive individuals. Further, we examined DQB1*02 and DRB4*01:01 alleles for their reported association with HPA-1a alloimmunization, in the context of DR-DQ haplotypes. Since ~ 80% of DQB1*02 alleles are linked to the DR3-DQ2 haplotype, the association might be coincidental. However, the DQB1*02:02-associated DR7-DQ2 haplotype was also overrepresented in alloimmunized women, suggesting a role for this allele or haplotype in HPA-1a alloimmunization. As DRB4*01:01 is predominantly associated with the DR7-DQ2 haplotype in HPA-1a-alloimmunized individuals, the reported association with FNAIT may be coincidental. Typing for DR-DQ haplotypes revealed important genetic associations with HPA-1a alloimmunization not evident from typing individual alleles, and the presence of different DRB3-associated DR-DQ haplotypes showed different prevalence of HPA-1a alloimmunization.
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http://dx.doi.org/10.1111/sji.12890DOI Listing
July 2020

Foetal and neonatal alloimmune thrombocytopenia - The role of the HLA-DRB3*01:01 allele for HPA-1a-immunisation and foetal/neonatal outcome.

Transfus Apher Sci 2020 Feb 31;59(1):102707. Epub 2019 Dec 31.

Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway.

Foetal and neonatal alloimmune thrombocytopenia (FNAIT) is the platelet counterpart of haemolytic disease of the foetus and newborn. Among Caucasians, around 80 % of FNAIT cases and some of the most severe cases, are caused by alloantibodies against the human platelet antigen 1a (HPA-1a). For around 3 decades it has been known that almost all HPA-1a-immunised women are HLA-DRB3*01:01 positive. The HLA molecule encoded by the HLA-DRA/DRB3*01:01 genes seems to be of crucial importance for initiating the immune response against HPA-1a. The HLA-DRB3*01:01 carrier status is not only important as a risk factor for immunisation, but does also have a significant impact on foetal/neonatal outcome. The possible role of HLA-DRB3*01:01 typing as tool for risk stratification is discussed.
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http://dx.doi.org/10.1016/j.transci.2019.102707DOI Listing
February 2020

Foetal and neonatal alloimmune thrombocytopenia-A rare, potentially serious and often underdiagnosed bleeding condition.

Transfus Apher Sci 2020 02 31;59(1):102703. Epub 2019 Dec 31.

Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway; University and Regional Laboratories, Region Skåne, Lund, Sweden. Electronic address:

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http://dx.doi.org/10.1016/j.transci.2019.102703DOI Listing
February 2020

Postnatal intervention for the treatment of FNAIT: a systematic review.

J Perinatol 2019 10 10;39(10):1329-1339. Epub 2019 Apr 10.

Division of Haematology/Oncology, CHU Sainte-Justine, University of Montreal, Montreal, Canada.

Objective: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is associated with life-threatening bleeding. This systematic review of postnatal management of FNAIT examined transfusion of human platelet antigen (HPA) selected or unselected platelets, and/or IVIg on platelet increments, hemorrhage and mortality.

Study Design: MEDLINE, EMBASE and Cochrane searches were conducted until 11 May 2018.

Result: Of 754 neonates, 382 received platelet transfusions (51%). HPA-selected platelets resulted in higher platelet increments and longer response times than HPA-unselected platelets. However, unselected platelets generally led to sufficient platelet increments to 30 × 10/L, a level above which intracranial hemorrhage or other life-threatening bleeding rarely occurred. Platelet increments were not improved with the addition of IVIg to platelet transfusion.

Conclusion: Overall, HPA-selected platelet transfusions were more effective than HPA-unselected platelets but unselected platelets were often effective enough to achieve clinical goals. Available studies do not clearly demonstrate a benefit for addition of IVIg to platelet transfusion.
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http://dx.doi.org/10.1038/s41372-019-0360-7DOI Listing
October 2019

HLA-DRB3*01:01 exhibits a dose-dependent impact on HPA-1a antibody levels in HPA-1a-immunized women.

Blood Adv 2019 04;3(7):945-951

Department of Laboratory Medicine, Diagnostic Clinic, University Hospital of North Norway, Tromsø, Norway.

HLA-DRB3*01:01 is a predisposing factor for human platelet antigen 1a (HPA-1a) immunization, which is responsible for most cases of fetal and neonatal alloimmune thrombocytopenia. The aim of this study was to investigate if the HLA-DRB3*01:01 allele imposes a dose-dependent effect on anti-HPA-1a levels and neonatal platelet counts. One hundred and thirty HPA-1a-immunized women were divided into 3 groups: HLA-DRB3*01:01 negative, HLA-DRB3*01:01 hemizygous or heterozygous, and HLA-DRB3*01:01 homozygous. The dose of the HLA-DRB3*01:01 allele was determined by sequencing exon 2 of the HLA-DRB3 gene followed by HLA-DRB3 and HLA-DRB1 typing of selected samples. Anti-HPA-1a levels at time of delivery and neonatal platelet counts were compared among groups. There was a significant dose-dependent effect of the HLA-DRB3*01:01 allele on anti-HPA-1a levels (global value [ ] = .0032). Median (range) anti-HPA-1a levels were 1.5 IU/mL (0.0-19.0 IU/mL), 21.1 IU/mL (0.0-1967 IU/mL), and 43.7 IU/mL (1.0-980 IU/mL) in women with 0, 1, and 2 copies of the HLA-DRB3*01:01 allele, respectively. There was also a significant, but opposite, dose-dependent effect of the mother's HLA-DRB3*01:01 allele on the platelet count of the newborn ( = .0155). Median (range) neonatal platelet counts were 241 × 10/L (59 × 10/L to 393 × 10/L), 107 × 10/L (4 × 10/L to 387 × 10/L) and 32 × 10/L (4 × 10/L to 352 × 10/L) for newborns of mothers with 0, 1, and 2 copies of the HLA-DRB3*01:01 allele, respectively. Thus, the HLA-DRB3*01:01 allele exhibits a dose-dependent impact on maternal anti-HPA-1a levels in HPA-1a-immunized women.
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http://dx.doi.org/10.1182/bloodadvances.2019032227DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457228PMC
April 2019

Fetal and neonatal alloimmune thrombocytopenia: recommendations for evidence-based practice, an international approach.

Br J Haematol 2019 05 3;185(3):549-562. Epub 2019 Mar 3.

University of Toronto, Toronto, Canada.

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) may result in severe bleeding, particularly fetal and neonatal intracranial haemorrhage (ICH). As a result, FNAIT requires prompt identification and treatment; subsequent pregnancies need close surveillance and management. An international panel convened to develop evidence-based recommendations for diagnosis and management of FNAIT. A rigorous approach was used to search, review and develop recommendations from published data for: antenatal management, postnatal management, diagnostic testing and universal screening. To confirm FNAIT, fetal human platelet antigen (HPA) typing, using non-invasive methods if quality-assured, should be performed during pregnancy when the father is unknown, unavailable for testing or heterozygous for the implicated antigen. Women with a previous child with an ICH related to FNAIT should be offered intravenous immunoglobulin (IVIG) infusions during subsequent affected pregnancies as early as 12 weeks gestation. Ideally, HPA-selected platelets should be available at delivery for potentially affected infants and used to increase the neonatal platelet count as needed. If HPA-selected platelets are not immediately available, unselected platelets should be transfused. FNAIT studies that optimize antenatal and postnatal management, develop risk stratification algorithms to guide management and standardize laboratory testing to identify high risk pregnancies are needed.
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http://dx.doi.org/10.1111/bjh.15813DOI Listing
May 2019

Risk of HPA-1a-immunization in HPA-1a-negative women after giving birth to an HPA-1a-positive child.

Transfusion 2019 04 6;59(4):1344-1352. Epub 2019 Feb 6.

Larix A/S, Herlev, Denmark.

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http://dx.doi.org/10.1111/trf.15152DOI Listing
April 2019

Maternal HPA-1a antibody level and its role in predicting the severity of Fetal/Neonatal Alloimmune Thrombocytopenia: a systematic review.

Vox Sang 2019 Jan 22;114(1):79-94. Epub 2018 Nov 22.

Department of Laboratory Medicine, Diagnostic Clinic, University Hospital of North Norway, Tromsø, Norway.

Background And Objectives: In Caucasians, fetal/neonatal alloimmune thrombocytopenia (FNAIT) is most commonly due to maternal HPA-1a antibodies. HPA-1a typing followed by screening for anti-HPA-1a antibodies in HPA-1bb women may identify first pregnancies at risk. Our goal was to review results from previous published studies to examine whether the maternal antibody level to HPA-1a could be used to identify high-risk pregnancies.

Materials And Methods: The studies included were categorized by recruitment strategies: screening of unselected pregnancies or samples analyzed from known or suspected FNAIT patients.

Results: Three prospective studies reported results from screening programmes, and 10 retrospective studies focused on suspected cases of FNAIT. In 8 studies samples for antibody measurement, performed by the monoclonal antibody immobilization of platelet antigen (MAIPA) assay, and samples for determining fetal/neonatal platelet count were collected simultaneously. In these 8 studies, the maternal antibody level correlated with the risk of severe thrombocytopenia. The prospective studies reported high negative predictive values (88-95%), which would allow for the use of maternal anti-HPA-1a antibody level as a predictive tool in a screening setting, in order to identify cases at low risk for FNAIT. However, due to low positive predictive values reported in prospective as well as retrospective studies (54-97%), the maternal antibody level is less suited for the final diagnosis and for guiding antenatal treatment.

Conclusion: HPA-1a antibody level has the potential to predict the severity of FNAIT.
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http://dx.doi.org/10.1111/vox.12725DOI Listing
January 2019

New elegant methods for maternal and fetal HPA-1a typing.

Transfusion 2018 10 21;58(10):2253-2254. Epub 2018 Sep 21.

University and Regional Laboratories, Lund, Sweden.

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http://dx.doi.org/10.1111/trf.14954DOI Listing
October 2018

Determination of fetal RHD type in plasma of RhD negative pregnant women.

Scand J Clin Lab Invest 2018 Sep 5;78(5):411-416. Epub 2018 Jun 5.

a Department of Immunology and Transfusion Medicine , Oslo University Hospital , Oslo , Norway.

Alloimmunization against the RhD antigen is the most common cause of hemolytic disease of the fetus and newborn. Antenatal anti-D prophylaxis in addition to postnatal anti-D prophylaxis reduces the number of RhD-immunizations compared to only postnatal administration. Cell-free fetal DNA released from the apoptotic trophoblastic placental cells into the maternal circulation can be used to determine the fetal RHD type in a blood sample from an RhD negative mother. Based on this typing, antenatal anti-D prophylaxis can be recommended only to RhD negative women carrying an RhD positive fetus, since only these women are at risk of developing anti-D. The objective was to establish and validate a method for non-invasive fetal RHD typing. The fetal RHD genotype was studied in 373 samples from RhD negative pregnant women (median gestational week 24). DNA extracted from plasma was analyzed for the presence/absence of RHD exon 7 and 10 in a real-time PCR. The RHD genotype of the fetus was compared with the serological RhD type of the newborn. In 234 samples, the fetal RHD test was positive and in 127 samples negative. There was one false positive and no false negative results. In 12 samples, the fetal RHD type could not be determined, in all of them due to a maternal RHD gene. This method gives a reliable detection of fetal RHD positivity in plasma from RhD negative pregnant women. Antenatal anti-D prophylaxis based on the predicted fetal RhD type will avoid unnecessary treatment of pregnant women carrying an RhD negative fetus.
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http://dx.doi.org/10.1080/00365513.2018.1475681DOI Listing
September 2018

Screening for fetal and neonatal alloimmune thrombocytopenia - lessons learned from a Norwegian screening program.

Acta Obstet Gynecol Scand 2018 06 5;97(6):766-767. Epub 2018 Mar 5.

Immunology Research Group, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway.

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http://dx.doi.org/10.1111/aogs.13320DOI Listing
June 2018

Linear decline of corrected platelet count increment within 24 hours after platelet transfusion in haematological patients: A prospective observational study.

Eur J Haematol 2017 Dec 16;99(6):559-568. Epub 2017 Oct 16.

Department of Clinical Sciences, Lund University, Lund, Sweden.

Objectives: The aim of this study was to prospectively explore the detailed longitudinal development of platelet increments in patients with chemotherapy-induced bone marrow aplasia during the first 24 hours after platelet transfusion.

Methods: Patients admitted to the Haematology department during 7 months, and fulfilled inclusion criteria were divided into 4 groups: Group 1, patients with acute leukaemia; Group 2, patients after autologous stem cell transplantation (SCT); Group 3, patients after allogeneic SCT; and Group 4, patients given platelet transfusion prior to intervention. We used frequent blood sampling within 24 hours after platelet transfusion to investigate the kinetics of platelet counts following transfusion.

Results And Conclusions: Fifty-four platelet transfusion occasions in patients with chemotherapy-induced bone marrow aplasia were included. The decrease in corrected count increment (CCI) 1-24 hours after platelet transfusions in all groups could be described as linear functions. For patients in the aggregated Groups 1-3, the decline was 2.0% ± 0.6% (mean ± standard deviation) per hour. For patients in Group 4, the decline of CCI was 2.8% ± 1.2% per hour. We found no differences between the groups, either in the rate of platelet elimination from the bloodstream or in the mean CCI, in the first 24 hours post-transfusion.
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http://dx.doi.org/10.1111/ejh.12974DOI Listing
December 2017

Fetal exposure to maternal human platelet antigen-1a does not induce tolerance. An analytical observational study.

PLoS One 2017 24;12(8):e0182957. Epub 2017 Aug 24.

Immunology Research Group, Department of Medical Biology, UiT The Artic University of Norway, Tromsø, Norway.

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a disease that may cause severe bleeding complications with risk of perinatal death or lifelong disability. The main cause of FNAIT is maternal antibodies against human platelet antigen (HPA)-1a. Both fetomaternal bleeding and transplacental trafficking of fetal cells during pregnancy could be the cause of alloimmunization. Persistence of fetal cells in the mother (fetal microchimerism) and maternal cells in the child (maternal microchimerism) are well-recognized phenomena. Thus, it could be envisaged that fetal exposure to the HPA-1a antigen could tolerize an HPA-1a negative female fetus and prevent production of anti-HPA-1a antibodies later in life if she becomes pregnant with an HPA-1a positive fetus. The objective of the current study was to assess if the risk of producing anti-HPA-1a antibodies and the severity of neonatal thrombocytopenia in HPA-1a negative women with HPA-1a positive mothers (i.e. the mother is HPA-1a/b), was lower than in HPA-1a negative women with HPA-1a negative mothers. HPA-1a negative women with HPA-1a antibodies, identified from a Norwegian screening study (1996-2004), where HPA-1 genotype of their mothers was available, were included in the study. The frequency of HPA-1a positive mothers to HPA-1a immunized daughters were compared to the calculated frequency in the general population. We did not find any difference in the frequency of HPA-1ab among mothers to daughters with HPA-1a antibodies as compared with the general population. Furthermore, acknowledging sample-size limitations, we neither found an association between the mothers' HPA type and their daughters' anti-HPA-1a antibody levels or any difference between the two groups of mothers (HPA-1ab vs HPA-1bb), with respect to frequency of thrombocytopenia in the children of their daughters with HPA-1a antibodies. Hence, there was no indication of tolerance against fetal HPA-1a antigen in HPA-1bb women who had been exposed to HPA-1a antigen during fetal development.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0182957PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5570354PMC
October 2017

Prevention of alloimmunization during pregnancy by prednisone and immunoglobulin G-What is the evidence?

Am J Reprod Immunol 2017 09 30;78(3). Epub 2017 May 30.

Clinical Immunology and Transfusion Medicine, Regional and University Laboratories, Lund, Sweden.

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http://dx.doi.org/10.1111/aji.12697DOI Listing
September 2017

Antenatal management in fetal and neonatal alloimmune thrombocytopenia: a systematic review.

Blood 2017 03 27;129(11):1538-1547. Epub 2017 Jan 27.

Fetal Medicine Unit, Mount Sinai Hospital, Toronto, ON, Canada.

Several strategies can be used to manage fetal or neonatal alloimmune thrombocytopenia (FNAIT) in subsequent pregnancies. Serial fetal blood sampling (FBS) and intrauterine platelet transfusions (IUPT), as well as weekly maternal IV immunoglobulin infusion (IVIG), with or without additional corticosteroid therapy, are common options, but optimal management has not been determined. The aim of this systematic review was to assess antenatal treatment strategies for FNAIT. Four randomized controlled trials and 22 nonrandomized studies were included. Pooling of results was not possible due to considerable heterogeneity. Most studies found comparable outcomes regarding the occurrence of intracranial hemorrhage, regardless of the antenatal management strategy applied; FBS, IUPT, or IVIG with or without corticosteroids. There is no consistent evidence for the value of adding steroids to IVIG. FBS or IUPT resulted in a relatively high complication rate (consisting mainly of preterm emergency cesarean section) of 11% per treated pregnancy in all studies combined. Overall, noninvasive management in pregnant mothers who have had a previous neonate with FNAIT is effective without the relatively high rate of adverse outcomes seen with invasive strategies. This systematic review suggests that first-line antenatal management in FNAIT is weekly IVIG administration, with or without the addition of corticosteroids.
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http://dx.doi.org/10.1182/blood-2016-10-739656DOI Listing
March 2017

Sensitive detection of platelet-specific antibodies with a modified MAIPA using biotinylated antibodies and streptavidin-coated beads.

J Immunol Methods 2016 07 5;434:9-15. Epub 2016 Apr 5.

Dept. of Clinical Immunology and Transfusion Medicine, Karolinska University Hospital, Stockholm, Sweden; Dept. of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden. Electronic address:

We have developed a modified monoclonal antibody immobilization of platelet antigens assay (MAIPA) with enhanced sensitivity in detecting antibodies against human platelet antigens (HPA), using biotinylated monoclonal antibodies, streptavidin-coated beads and detection by flow cytometry. The beads-MAIPA gave superior signal-to-noise resolution (>10-fold higher) for detection of anti-HPA-1a and anti-HPA-5b compared with the in-house standard MAIPA. Also, efficient and reproducible detection of anti-HPA-15 (CD109) was shown. The enhanced sensitivity was confirmed using WHO International Reference Reagents for anti-HPA-1a, anti-HPA-3a and anti-HPA-5b, which allowed comparison of detection endpoints with other laboratories. Finally, the beads-MAIPA was validated for quantification of anti-HPA-1a. The lower limit of quantification was 0.4IU/mL for beads-MAIPA, compared to 1IU/mL previously reported for standard MAIPA. Based on improved performance against all HPA-antibodies tested, the beads-MAIPA has replaced the standard MAIPA in our laboratory in diagnostics of conditions due to HPA-immunization, such as fetal and neonatal alloimmune thrombocytopenia (FNAIT).
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http://dx.doi.org/10.1016/j.jim.2016.04.001DOI Listing
July 2016

Fetal and neonatal alloimmune thrombocytopenia.

Semin Fetal Neonatal Med 2016 Feb 20;21(1):19-27. Epub 2016 Jan 20.

Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Toronto Platelet Immunobiology Group, Toronto, ON, Canada; Department of Laboratory Medicine, Keenan Research Centre for Biomedical Science, St Michael's Hospital, Toronto, ON, Canada; Canadian Blood Services, Toronto, ON, Canada; Department of Clinical Immunology and Transfusion Medicine, University and Regional Laboratories Region Skåne, Lund, Sweden; Department of Medicine, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada. Electronic address:

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is an alloimmune disorder resulting from platelet opsonization by maternal antibodies that destroy fetal platelets. The major risk of FNAIT is severe bleeding, particularly intracranial hemorrhage. Miscarriage has also been reported but the incidence requires further study. Analogous to adult autoimmune thrombocytopenia (ITP), the major target antigen in FNAIT is the platelet membrane glycoprotein (GP)IIbIIIa. FNAIT caused by antibodies against platelet GPIbα or other antigens has also been reported, but the reported incidence of the anti-GPIbα-mediated FNAIT is far lower than in ITP. To date, the maternal immune response to fetal platelet antigens is still not well understood and it is unclear why bleeding is more severe in FNAIT than in ITP. In this review, we introduce the pathogenesis of FNAIT, particularly those new discoveries from animal models, and discuss possible improvements for the diagnosis, therapy, and prevention of this devastating disease.
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http://dx.doi.org/10.1016/j.siny.2015.12.004DOI Listing
February 2016

Acoustophoretic removal of proteins from blood components.

Biomed Microdevices 2015 Oct;17(5):95

Department of Biomedical Engineering, Lund University, Lund, Sweden,

This work presents the development of a miniaturized system for removing plasma proteins and other low-molecular-weight compounds from red blood cell (RBC) concentrate in a simple one-step-process using integrated ultrasound. The technology utilizes the principles of acoustophoresis to transfer the RBCs from the original plasma-containing solution into a protein-free SAG-M additive solution in a continuous flow process. The preparation of protein free RBC concentrate is important for blood transfusion to patients suffering from immunoglobulin A (IgA)-deficiency and developing antibodies against IgA. We show a nearly complete removal of both albumin and IgA from concentrated RBCs via this one-step-processes in samples obtained from RBC concentrate. The cell recovery of our technology is close to 97%, compared to just above 90% of the current procedure of repeated dilution and centrifugation steps. This work clearly shows the potential of integrated acoustophoresis in a miniaturized system for clinical applications.
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http://dx.doi.org/10.1007/s10544-015-0003-5DOI Listing
October 2015

Paroxysmal nocturnal haemoglobinuria at Oslo University Hospital 2000-2010.

Tidsskr Nor Laegeforen 2015 Jun 16;135(11):1039-43. Epub 2015 Jun 16.

Avdeling for immunologi og transfusjonsmedisin Oslo universitetssykehus.

Background: Paroxysmal nocturnal haemoglobinuria (PNH) is a rare haematological disease characterised by chronic haemolysis, pancytopenia and venous thrombosis. The condition is attributable to a lack of control of complement attack on erythrocytes, thrombocytes and leukocytes, and can be diagnosed by means of flow cytometry. In this quality assurance study, we have reviewed information from the medical records of all patients tested for PNH using flow cytometry at our laboratory over a ten-year period.

Material And Method: In the period 2000-2010 a total of 28 patients were tested for PNH using flow cytometry at the Department of Immunology and Transfusion Medicine, Oslo University Hospital. We have reviewed the results of these examinations retrospectively together with information from medical records and transfusion data for the patients concerned.

Results: Flow cytometry identified 22 patients with PNH: four with classic disease and 18 with PNH secondary to another bone marrow disease. Five patients had atypical thrombosis. Seventeen patients received antithymocyte globulin or drug treatment; of these, six recovered from their bone marrow disease, while six died and five had a need for long-term transfusion. Five patients with life-threatening bone marrow disease underwent allogeneic stem cell transplantation, three of whom died. Six of 22 patients received eculizumab; the need for transfusion has been reduced or eliminated in three patients treated with eculizumab over a longer period.

Interpretation: Flow cytometry identified PNH in a majority of patients from whom we obtained samples. Most patients had a PNH clone secondary to bone marrow failure. Atypical thrombosis should be borne in mind as an indication for the test. Treatment with eculizumab is relevant for selected patients with PNH.
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http://dx.doi.org/10.4045/tidsskr.14.0444DOI Listing
June 2015

Mechanisms and prevention of alloimmunization in pregnancy.

Obstet Gynecol Surv 2013 Jul;68(7):526-32

Department of Clinical Immunology and Transfusion Medicine, University and Regional Laboratories Region Skåne, Lund, Sweden.

Transfusion only occasionally gives rise to antibody production, because blood cells per se are not markedly immunogenic. However, the immunological changes that occur during pregnancy increase the risk of alloimmunization against red blood cells, platelets, and/or leukocytes. Fetal-maternal bleeding during pregnancy or in relation to delivery is the antigenic stimuli for immunization against red blood cells, whereas other mechanisms, such as trophoblast-derived microparticles, may also play a role in the production of antibodies against platelets. Antibody-mediated immune suppression has for 4 decades successfully been used for prevention of RhD immunization. Result from a mouse model of fetal and neonatal alloimmune thrombocytopenia (FNAIT) suggests that the same principle may be applied for the prevention of FNAIT. A European Union-funded consortium is presently in the process of developing a hyperimmune anti-human platelet antigen 1a (HPA-1a) immunoglobulin G. The idea is to prevent HPA-1a immunization by administering the drug to nonimmunized HPA-1a-negative women after delivery of an HPA-1a-positive child. The anti-HPA-1a will be purified from plasma collected from women who previously have given birth to a child with FNAIT caused by anti-HPA-1a. If the results of the planned phase III trial are favorable, it is possible that a product for prevention of FNAIT will be available within this decade.
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http://dx.doi.org/10.1097/OGX.0b013e3182947ce4DOI Listing
July 2013

3',4'-Dimethoxyflavone and valproic acid promotes the proliferation of human hematopoietic stem cells.

Stem Cell Res Ther 2013 May 24;4(3):60. Epub 2013 May 24.

Introduction: Human hematopoietic stem cells (HSCs) have been clinically used for transplantation and gene and cellular therapy for more than 4 decades. However, this use is limited because of the challenges in the ex vivo culturing of HSCs. The major hurdle is to amplify these cells without losing their self-renewing property.

Methods: In our study, we tested 3',4'-dimethoxyflavone (3'4'-DMF) and valproic acid (VPA) on the ex vivo expansion of HSCs under both normoxic (20% O2) and hypoxic (1% O2) conditions. 3'4'-DMF is a widely used anticancer drug that acts as a competitive antagonist of the aryl hydrocarbon receptor. VPA is a potent inhibitor of histone deacetylase and is used in the treatment of neurologic disorders.

Results: Culturing HSCs (from mobilized peripheral blood) under normoxia, with 3'4'-DMF and VPA, highly preserved the CD34 positivity (3'4'-DMF, 22.1%, VPA, 20.3%) after 1 week and strongly enhanced the CD34(+) cells (3'4'-DMF, 27.8 fold; VPA, 34.1 fold) compared with the control cultures (11.6% and 14.4 fold). Addition of 3'4'-DMF and VPA also resulted in more primary colonies and replating efficiency compared with control cultures. Although no significant effect was observed on the enhancement of CD34(+) cells under hypoxia, the number of primary colonies was significantly higher than the control cultures.

Conclusions: Based on these findings, this study presents, for the first time, in vitro evidence for a new and relevant effect of 3'4'-DMF on human HSCs. In addition, the results suggest a potential clinical use of 3'4'-DMF and VPA in HSC therapy.
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http://dx.doi.org/10.1186/scrt208DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3706763PMC
May 2013

Towards a prophylactic treatment of HPA-related foetal and neonatal alloimmune thrombocytopenia.

Curr Opin Hematol 2012 Nov;19(6):469-74

Department of Clinical Immunology and Transfusion Medicine, University and Regional Laboratories Region Skåne, Lund, Sweden.

Purpose Of Review: The purpose of the review is to show the similarities between haemolytic disease of the foetus and newborn (HDFN) and foetal and neonatal alloimmune thrombocytopenia (FNAIT) and to describe the background and challenges related to the current endeavours of developing a prophylaxis against FNAIT. The rationale for this prophylaxis is similar to the prophylaxis which has been used with great success for the last 40 years against RhD-associated HDFN. The idea is to prevent human platelet antigen (HPA)-1a-associated FNAIT by administering anti-HPA-1a immunoglobulin G (IgG) to nonimmunized HPA-1a-negative women after delivery of an HPA-1a-positive child.

Recent Findings: Results from a Norwegian screening and intervention study on FNAIT have indicated that about 75% of women with antibodies against HPA-1a are immunized in relation to delivery. This observation leads to the possibility of preventing HPA-1a-associated FNAIT in the same way as today's prevention of HDFN. Results from a proof-of-concept study in a murine FNAIT model have shown that the production of alloantibodies against platelets can be suppressed by administrating antiplatelet antibodies after the antigenic challenge. Even more interesting, the prophylactic antiplatelet antibodies could also significantly reduce the clinical consequences of FNAIT in this FNAIT model.

Summary: These novel observations have paved the way for clinical studies. Production and testing of anti-HPA-1a IgG for clinical use will be carried out by a European Union-funded consortium. If the results from the clinical trial are favourable, there is a chance that a medicinal product for the prevention of FNAIT will be available within this decade.
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http://dx.doi.org/10.1097/MOH.0b013e328358f86cDOI Listing
November 2012

Biological response modifiers in photochemically pathogen-reduced versus untreated apheresis platelet concentrates.

Transfusion 2013 Jan 7;53(1):147-55. Epub 2012 May 7.

Department of Immunology and Transfusion Medicine, Oslo University Hospital, Ullevaal, Oslo, Norway.

Background: Lipids and other biologically active substances accumulate in platelet concentrates (PCs) during storage. Some of these substances have been suggested to modulate immune responses and to play a pathogenic role in the development of transfusion-related acute lung injury. This study compared the content and impact of some biological response modifiers in PCs treated with pathogen reduction (PR) technology and nontreated PCs.

Study Design And Methods: Apheresis PCs (n = 12) were split in two: one split was subjected to PR treatment (INTERCEPT, Cerus Corp.) and the other split was left untreated. Basic characterization and content of vascular endothelial growth factor (VEGF) and sCD154 were measured. Lipopolysaccharide (LPS)-induced secretion of interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) was measured after incubation of heparinized whole blood with platelet (PLT) supernatants. The supernatants' neutrophil (PMN)-priming capacity, and thereby activation of the NADPH oxidase, was measured as the rate of superoxide anion production after formyl-Met-Leu-Phe activation. Lipids were extracted from the supernatants on Day 6 and tested for PMN-priming activity.

Results: Supernatants from PR-treated PCs demonstrated significantly higher mean PLT volume (MPV) and O(2) , lower pH, CO(2) , and HCO(3-) , and significantly less LPS-induced TNF-α secretion compared to untreated PCs. No differences in swirling, PLT count, potassium levels, glucose consumption, lactate production, IL-10, VEGF, sCD154, or PMN-priming activity were found between the groups over time.

Conclusion: INTERCEPT PR treatment caused no substantial differences in PCs, except for minor changes in MPV and metabolic variables. Further studies are needed to explain the differences in the LPS-induced TNF-α secretion.
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http://dx.doi.org/10.1111/j.1537-2995.2012.03681.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3690765PMC
January 2013

Toward a prophylaxis against fetal and neonatal alloimmune thrombocytopenia: induction of antibody-mediated immune suppression and prevention of severe clinical complications in a murine model.

Transfusion 2012 Jul 17;52(7):1446-57. Epub 2012 Jan 17.

University Hospital of North Norway, Tromsø, Norway.

Background: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a severe bleeding disorder caused by maternal antibody-mediated destruction of fetal or neonatal platelets (PLTs). Results from our recent large screening study suggest that the pathophysiology of FNAIT is more similar to hemolytic disease of the fetus and newborn (HDFN) than previously thought. Immunization against HPA-1a might therefore be preventable by a prophylactic regimen of inducing antibody-mediated immune suppression (AMIS), which has been documented to be a useful prophylaxis against HDFN. This preclinical proof-of-concept study investigated whether passive administration of anti-β3 integrin could induce AMIS and thereby prevent clinical complications of FNAIT.

Study Design And Methods: A murine model of FNAIT using β3 integrin (GPIIIa)-deficient (β3-/-) mice was employed for this study. AMIS in β3-/- mice was induced by intravenous administration of human anti-HPA-1a immunoglobulin G or murine anti-β3 antisera given as prophylaxis after transfusion of HPA-1a-positive human PLTs or murine wild-type PLTs, respectively.

Results: AMIS against both human and murine PLT antigens was induced using this prophylactic approach, reducing the amount of maternal PLT antibodies by up to 90%. Neonatal PLT counts were significantly increased and pregnancy outcome was improved in a dose-dependent manner. The incidence of intracranial hemorrhage, miscarriage, and dead-born pups in mice receiving high-dose prophylaxis was reduced to that of normal controls. We also observed that the severity of thrombocytopenia inversely correlated with birth weight.

Conclusion: This work conceptually proves that prophylactic administration of PLT antibodies induces AMIS and prevents poor pregnancy outcome in FNAIT.
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http://dx.doi.org/10.1111/j.1537-2995.2011.03480.xDOI Listing
July 2012

Glycogen synthase kinase-3 (GSK-3) inhibition induces apoptosis in leukemic cells through mitochondria-dependent pathway.

Leuk Res 2012 Apr 15;36(4):499-508. Epub 2011 Dec 15.

Department of Immunology and Transfusion Medicine, Oslo University Hospital, Oslo, Norway.

The roles of glycogen synthase kinase-3 (GSK-3) in cell survival and apoptosis are controversial. We examined the effect of a specific GSK-3 inhibitor (SB-415286) on the regulation of leukemic cells proliferation and apoptosis. SB-415286 (40 μM) induced cell growth inhibition, β-catenin stabilization, cell cycle arrest in G(2)/M phase, cyclin B1 downregulation, and apoptosis in leukemic cell lines KG1a, K562, and CMK. Blocking the death receptor pathway by using a specific inhibitor of caspase-8, did not inhibit SB-415286-induced apoptosis. This indicates that activation of caspase-8 is part of the intrinsic apoptotic pathway and occurs downstream of mitochondria membrane potential depolarization mediated by other caspases. Furthermore, we found that depolarization of mitochondria membrane caused by GSK-3 inhibition is regulated by dephosphorylation of anti-apoptotic protein Bcl-2 and downregulation of Bcl-xL. Thus, inhibition of GSK-3-induced apoptosis of leukemic cells could be an attractive target for treatment of leukemia.
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http://dx.doi.org/10.1016/j.leukres.2011.11.013DOI Listing
April 2012

The development of severe neonatal alloimmune thrombocytopenia due to anti-HPA-1a antibodies is correlated to maternal ABO genotypes.

Clin Dev Immunol 2012 2;2012:156867. Epub 2011 Nov 2.

Department of Laboratory Medicine, University Hospital of North Norway, 9038 Tromsø, Norway.

Background: Maternal alloantibodies against HPA-1a can cross placenta, opsonize foetal platelets, and induce neonatal alloimmune thrombocytopenia (NAIT). In a study of 100, 448 pregnant women in Norway during 1995-2004, 10.6% of HPA-1a negative women had detectable anti-HPA-1a antibodies.

Design And Methods: A possible correlation between the maternal ABO blood group phenotype, or underlying genotype, and severe thrombocytopenia in the newborn was investigated.

Results: We observed that immunized women with blood group O had a lower risk of having a child with severe NAIT than women with group A; 20% with blood group O gave birth to children with severe NAIT, compared to 47% among the blood group A mothers (relative risk 0.43; 95% CI 0.25-0.75).

Conclusion: The risk of severe neonatal alloimmune thrombocytopenia due to anti-HPA-1a antibodies is correlated to maternal ABO types, and this study indicates that the observation is due to genetic properties on the maternal side.
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http://dx.doi.org/10.1155/2012/156867DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3216343PMC
March 2012

Recovery, survival, and function of transfused platelets and detection of platelet engraftment after allogeneic stem cell transplantation.

Transfusion 2012 Jun 16;52(6):1321-32. Epub 2011 Nov 16.

Department of Immunology and Transfusion Medicine, Oslo University Hospital HF, Ullevaal, Norway.

Background: Recovery and survival of transfused platelets (PLTs) are usually assessed by radioisotope labeling methods for evaluation of transfusion efficacy and new progress in the processing of PLT concentrates. Alternative, nonradioactive methods are warranted.

Study Design And Methods: A multicolor flow cytometry method was developed for simultaneous studies of recovery, survival, and function of transfused PLTs. Eight consecutive patients undergoing allogeneic stem cell transplantation (TX) were transfused with apheresis PLTs of nonself human leukocyte antigen (HLA) Class I types, and HLA Class I discrepancy between donor and recipient was used to identify transfused PLTs. Hematologic status and HLA Class I surface expression were analyzed immediately before transfusion, 1 and 6 hours after transfusion, and daily during the subsequent week. PLT activation was assessed by surface expression of CD63, CD62P, or CD42a, before and after stimulation with thrombin receptor agonist peptide.

Results: PLT recovery was 43, 41, and 31% for fresh (5-72 hr old) and 30, 27, and 17% for stored (73-148 hr old) PLTs, after 1, 6, and 15 to 28 hours, respectively. Survival of fresh versus stored PLTs were 160 and 105 hours, respectively. Spontaneous PLT activation and residual activation potential were almost equal for fresh and stored PLTs. PLT engraftment was detected between Day 7 and Day 9, which was significantly earlier than first sign of neutrophil engraftment (Days 11-19; p=0.01).

Conclusion: Flow cytometry is an attractive alternative to radiolabeling of PLTs for simultaneous studies of survival, recovery, and function of transfused PLTs and early detection of PLT engraftment after allogeneic stem cell TX.
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http://dx.doi.org/10.1111/j.1537-2995.2011.03442.xDOI Listing
June 2012
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