Publications by authors named "Zulma M Medeiros"

5 Publications

  • Page 1 of 1

Assessment of a recombinant protein from Leishmania infantum as a novel tool for Visceral Leishmaniasis (VL) diagnosis in VL/HIV co-infection cases.

PLoS One 2021 17;16(5):e0251861. Epub 2021 May 17.

Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Pernambuco, Brazil.

Visceral Leishmaniasis and HIV-AIDS coinfection (VL/HIV) is considered a life-threatening pathology when undiagnosed and untreated, due to the immunosuppression caused by both diseases. Serological tests largely used for the VL diagnosis include the direct agglutination test (DAT), ELISA and immunochromatographic (ICT) assays. For VL diagnosis in HIV infections, different studies have shown that the use of the DAT assay facilitates the VL diagnosis in co-infected patients, since the performance of the most widely used ELISA and ICT tests, based on the recombinant protein rK39, are much less efficient in HIV co-infections. In this scenario, alternative recombinant antigens may help the development of new serological diagnostic methods which may improve the VL diagnosis for the co-infection cases. This work aimed to evaluate the use of the recombinant Lci2 antigen, related to, but antigenically more diverse than rK39, for VL diagnosis in co-infected sera through ELISA assays. A direct comparison between recombinant Lci2 and rK39 was thus carried out. The two proteins were first tested using indirect ELISA with sera from VL afflicted individuals and healthy controls, with similar performances. They were then tested with two different sets of VL/HIV co-infected cases and a significant drop in performance, for one of these groups, was observed for rK39 (32% sensitivity), but not for Lci2 (98% sensitivity). In fact, an almost perfect agreement (Kappa: 0.93) between the Lci2 ELISA and DAT was observed for the coinfected VL/HIV patients. Lci2 then has the potential to be used as a new tool for the VL diagnosis of VL/HIV co-infections.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251861PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8128258PMC
May 2021

A Flow Cytometry-Based Serological Assay to Detect Visceral Leishmaniasis in HIV-Infected Patients.

Front Med (Lausanne) 2021 30;8:553280. Epub 2021 Apr 30.

Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Brazil.

Visceral Leishmaniasis (VL) is a severe parasitic disease that has emerged as an important opportunistic condition in HIV-infected patients and whose control is impaired by inaccurate identification. This is mainly due to the serological tests used for VL having a reduced performance in cases of VL-HIV coinfection due to a low humoral response. In this situation, however, a positive test has even greater diagnostic value when combined with the clinical status. This study aimed to evaluate the application and performance of flow cytometry to detect anti- antibodies in HIV-infected patients. Sera from VL/HIV coinfected patients, characterized using "gold standard" techniques, were compared with sera from healthy controls plus sera from HIV-infected individuals. The flow cytometry results were expressed as levels of IgG reactivity, based on the percentage of positive fluorescent parasites (PPFP). A ROC curve analysis of a serum titration indicated a PPFP of 1.26% as being the cutoff point to segregate positive and negative results. At the 1:2,048 dilution, with 89% sensitivity and 83% specificity, flow cytometry showed greater sensitivity in relation to the serological tests evaluated. Futhermore, flow cytometry was the only assay that positively identified all VL-HIV patients with quantified HIV load. Together, these findings suggest that flow cytometry may be used as an alternative serological approach for VL identification and as a tool to characterize the humoral response against in HIV-infected patients.
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http://dx.doi.org/10.3389/fmed.2021.553280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8119745PMC
April 2021

Case Report: Severe Visceral Leishmaniasis in a Patient with HIV Coinfection Undergoing Treatment for Erythema Nodosum Leprosum.

Am J Trop Med Hyg 2020 12 3;103(6):2253-2256. Epub 2020 Sep 3.

Programa de Pós-Graduação em Biociências, Universidade Federal do Vale do São Francisco, Petrolina, Brazil.

We report a case of visceral leishmaniasis (VL)/HIV coinfection in a patient undergoing regular antiretroviral therapy and treatment with thalidomide for erythema nodosum leprosum. He presented at a health service with high fever, chills, asthenia, pale skin, lower limb edema, hepatomegaly, and splenomegaly. Visceral leishmaniasis was confirmed by direct examination, and serological and molecular tests. Serum levels of Th1/Th2 cytokines were measured. The patient began treatment with liposomal amphotericin B, with good clinical response; however, VL recurred 6 months later. Treatment was reinitiated, maintaining secondary prophylaxis with liposomal amphotericin B. The patient showed clinical improvement with important recovery of CD4 T-lymphocyte count.
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http://dx.doi.org/10.4269/ajtmh.20-0567DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695079PMC
December 2020

Performance evaluation of anti-fixed Leishmania infantum promastigotes immunoglobulin G (IgG) detected by flow cytometry as a diagnostic tool for visceral Leishmaniasis.

J Immunol Methods 2019 06 25;469:18-25. Epub 2019 Feb 25.

Fundação Oswaldo Cruz (Fiocruz-Pernambuco), Instituto Aggeu Magalhães, Recife, Pernambuco, Brazil.

Visceral Leishmaniasis (VL) is a severe disease, caused by the protozoans Leishmania infantum and L. donovani that is widely diagnosed using serological tools. These, however, have limitations in performance that limit their use for the correct identification of the cases. This study aimed to evaluate the performance of flow cytometry with fixed parasites for VL diagnosis, comparing it with four other serological tests. Samples from two endemic VL regions in Brazil, diagnosed by direct examination (DG1) and by at least two or one standard serological test (DG2 and DG3, respectively), as well as patients with chronic Chagas' disease (CG1) and healthy controls (CG2) were used in this study. The flow cytometry results were expressed as levels of IgG reactivity, based on the percentage of positive fluorescent parasites (PPFP). Using a 1:4096 serum dilution, a ROC curve analysis of the serum titration on flow cytometry has indicated a PPFP of 2% as the cutoff point to segregate positive and negative results. In the present study, flow cytometry had the best performance for DG1 (sensitivity of 96%) while rK39 (imunocromagraphic rapid test) and DAT (Direct agglutination test) were also associated with high sensitivity and specificity. The substantial agreement and kappa indexes observed suggested similar performances between these two tests and flow cytometry. IFAT (Immunofluorescent antibody test) and ELISA (Enzyme-linked immunosorbent assay) had lower performances and the lower values of agreement with flow cytometry. Together, these findings suggest that although adjustments are needed in order to reduce cross reactivity with other trypanosomatids, flow cytometry has the potential to be a safe serological alternative for the diagnosis of VL.
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http://dx.doi.org/10.1016/j.jim.2019.02.009DOI Listing
June 2019

Evaluation of a new set of recombinant antigens for the serological diagnosis of human and canine visceral leishmaniasis.

PLoS One 2017 28;12(9):e0184867. Epub 2017 Sep 28.

Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz (Fiocruz-Pernambuco), Recife, Pernambuco, Brazil.

Current strategies for the control of zoonotic visceral leishmaniasis (VL) rely on its efficient diagnosis in both human and canine hosts. The most promising and cost effective approach is based on serologic assays with recombinant proteins. However, no single antigen has been found so far which can be effectively used to detect the disease in both dogs and humans. In previous works, we identified Leishmania infantum antigens with potential for the serodiagnosis of VL. Here, we aimed to expand the panel of the available antigens for VL diagnosis through another screening of a genomic expression library. Seven different protein-coding gene fragments were identified, five of which encoding proteins which have not been previously studied in Leishmania and rich in repetitive motifs. Poly-histidine tagged polypeptides were generated from six genes and evaluated for their potential for diagnosis of VL by ELISA (Enzyme Linked ImmunoSorbent Assay) with sera from infected humans and dogs. None of those was valid for the detection of human VL (26-52% sensitivity) although their performance was increased in the canine sera (48-91% sensitivity), with one polypeptide useful for the diagnosis of canine leishmaniasis. Next, we assayed a mixture of three antigens, found to be best for human or canine VL, among 13 identified through different screenings. This "Mix" resulted in similar levels of sensitivity for both human (84%) and canine (88%) sera. With improvements, this validates the use of multiple proteins, including antigens identified here, as components of a single system for the diagnosis of both forms of leishmaniasis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0184867PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5619722PMC
October 2017