STEVEN SOL WITKIN
Projetos de Pesquisa
Unidades Organizacionais
LIM/52 - Laboratório de Virologia, Hospital das Clínicas, Faculdade de Medicina
9 resultados
Resultados de Busca
Agora exibindo 1 - 9 de 9
- Detection and analysis of blood donors seropositive for syphilis(2021) ATTIE, Adriana; ALMEIDA-NETO, Cesar de; WITKIN, Steven S.; DERRIGA, Juliana; NISHIYA, Anna S.; FERREIRA, Jerenice E.; COSTA, Natalia de Souza Xavier; SALLES, Nanci Alves; FACINCANI, Tila; LEVI, Jose E.; SABINO, Ester C.; ROCHA, Vanderson; MENDRONE-JR, Alfredo; FERREIRA, Suzete C.Background The increasing incidence of syphilis worldwide has called attention to the risk of transmission by transfusion. Aims To determine the prevalence of active syphilis in blood donors and characterise the serological profile of syphilis-positive donors. Methods Samples positive for Treponema pallidum using the chemiluminescent microparticle immunoassay (CMIA) during blood donor screening from 2017 to 2018 were tested by the Venereal Disease Research Laboratory (VDRL) non-treponemal test and for anti-T. pallidum IgM by ELISA (Immunoassay Enzyme test for detection of IgM antibodies). The INNO-LIA Syphilis test (Line Immuno Assay solid test for confirmation antibodies to Treponema pallidum) was performed as a confirmatory test on samples that were positive on ELISA-IgM but negative on VDRL. ELISA-IgM (+) samples were also tested for T. pallidum DNA in sera by real-time polymerase chain reaction (PCR). Results Of 248 542 samples screened, 1679 (0.67%) were positive for syphilis by CMIA. Further analysis was performed on 1144 (68.1%) of these samples. Of those tested, 16% were ELISA IgM(+)/VDRL(+), 16.5% were ELISA IgM(-)/VDRL(+), 4.1% were ELISA IgM(+)/VDRL(-), and 63.4% were ELISA IgM (-)/VDRL(-). The INNO-LIA Syphilis test results were 33 (3%) positive, 2 (0.2%) undetermined and 12 (1%) negative. Of the 230 EIA-IgM(+) samples (20.1%), 5 (2.2%) were PCR positive. The prevalence of active syphilis in 2017 and 2018 was 0.1% and 0.07%, respectively, and overall prevalence of serologic markers for syphilis was highest among male, unmarried, 25-34-year-olds with a high school education and who were first-time donors. Conclusion There is a risk of transfusion-transmitted syphilis in blood banks that exclusively use the VDRL test for donor screening, as is currently the situation in some Brazilian blood centres, as well as in other blood centres around the world.
- Prevalence and clinical consequences of Hepatitis C virus infection in patients undergoing hematopoietic stem cell transplantation(2024) DIAZ, Ana Claudia Marques Barbosa; WITKIN, Steven Sol; ALMEIDA-NETO, Cesar de; MENDRONE-JUNIOR, Alfredo; ROCHA, Vanderson; COSTA, Silvia Figueiredo; RAMOS, Jessica Fernandes; MENDES-CORREA, Maria CassiaHepatitis C virus (HCV) infection is a significant cause of morbidity and mortality among hematopoietic stem cell transplant (HCT) recipients. In Brazil, its occurrence in HCT recipients remains undetermined. We now report on HCV prevalence in HCT recipients and its clinical consequences. The medical records of all HCT recipients seen at Hospital das Clinicas, Sao Paulo University Medical School, from January 2010 to January 2020 were reviewed to determine HCV serostatus. A retrospective analysis of medical charts was undertaken on all seropositive cases to determine HCV genotype, presence of liver fibrosis, co-infections with other viruses, previous treatments, and clinical evolution of liver pathology after HCT. Of the 1,293 HCT recipients included in the study, seven (0.54%) were HCV antibody-positive and five (0.39%) were also viremic for HCV-RNA. Four of these individuals had moderate to severe liver fibrosis (METAVIR F2/F3) and one was cirrhotic. Two of the viremic patients developed acute liver dysfunction following transplantation. All patients had their acute episode of liver dysfunction resolved with no further complications. Four of the viremic patients were treated for HCV infection with direct acting agents (DAA). Information regarding HCV treatment was lacking for one of the viremic HCV patients due to loss of follow up. Sustained anti-virologic responses were observed in three cases after the use of DAA. The detection of HCV in hematological adults undergoing HCT and its successful treatment with DAA highlight the necessity of testing for HCV both prior to and following transplantation.
- Occult and active hepatitis B virus detection in donated blood in Sao Paulo, Brazil(2021) NISHIYA, Anna S.; LEVI, Jose E.; ALMEIDA-NETO, Cesar de; WITKIN, Steven S.; FERREIRA, Suzete C.; BASSIT, Leda; SABINO, Ester C.; DI-LORENZO-OLIVEIRA, Claudia; SALLES, Nanci A.; COUTINHO, Adenilson S.; BELLESA, Maria A.; ROCHA, Vanderson; MENDRONE-JR, AlfredoBackground The present study determined the HBV antigen, antibody, and DNA status in blood donations deemed to be HBV positive. Individuals with an occult HBV infection (OBI), defined as being positive for HBV DNA but negative for HBV surface antigen (HBsAg), as well as those with active infection (HBsAg-positive), were identified and characterized. Study Design and Methods From a total pool if 198,363 blood donations, we evaluated in a cross-sectional study, 1106 samples that were positive in screening tests for antibody to HBV core antigen (HBcAb), HBsAg, and/or HBV DNA by nucleic acid testing (NAT-HBV). The presence of genetic variants in the HBV pol/S gene in individuals with an active HBV infection was also determined. Results OBIs were detected in six of 976 samples (0.6%) that were positive only for HBcAb. The rate of HBV active infection was 0.024% (48/198,363) and there was a predominance of HBV sub-genotype A1 (62.2%, 28/45), followed by D3 (17.8%, 8/45). Mutations in the S gene were found in 57.8% (26/45) and immune escape mutations in 37.8% (17/45) of active HBV-infected donors. Among them, T123N, G145A, and D144G high-impact immune escape mutations were identified. Conclusion Highly sensitive molecular tests improve the capacity to detect OBIs. When NAT is performed in pooled samples, HBcAb test has value in the detection of donors with OBI and improves transfusion safety. Mutations in the S gene are frequent in HBsAg-positive blood, including those associated with diagnostic failure and vaccine escape mutations.
- Are different motivations and social capital score associated with return behaviour among Brazilian voluntary non-remunerated blood donors?(2020) ESTRADA, Fernanda G. M. D.; OLIVEIRA, Claudia D. L.; SABINO, Ester C.; CUSTER, Brian; GONCALEZ, Thelma T.; MURPHY, Edward L.; TELES, Dahra; MENDRONE-JUNIOR, Alfredo; WITKIN, Steve S.; ALMEIDA-NETO, Cesar deBackground We examined the association between social capital score, motivator factors and demographic and donation characteristics and donor return at three Brazilian blood centres in Recife, Sao Paulo and Belo Horizonte. Material and methods A total of 5974 donors were interviewed about motivation factors to donate and cognitive and structural social capital just before an effective donation in three Brazilians blood centres in 2009. We assessed the return to a new donation within 2 years for each of these donors. Demographic and donation characteristics, motivators and scores of social capital and their association with donors' return were assessed. Results Overall, 3123 (52.3%) of the study subjects returned for a blood donation at least once. Predictors of donors' return were male gender (adjusted odds ratio [AOR] = 1.6, 1.3-1.9, for replacement and AOR = 1.3, 1.2-1.6, for community donors), previous donation (AOR = 2.7, 2.3-3.3, for replacement and AOR = 2.9, 2.5-3.5, for community donors) and high altruism (AOR = 1.3, 1.1-1.7, for replacement and AOR = 1.2, 1.0-1.5, for community donors). Altruism was the only motivator associated with return behaviour. Donors from Recife and Sao Paulo were more likely to return for replacement and/or for community donations than donors from Belo Horizonte. There was no association between social capital score and donor return behaviour. Conclusion The likelihood to return for a subsequent blood donation is dependent upon characteristics of individual donors and also varies in different regions of Brazil. However, social capital was not associated with the likelihood of return behaviour. A better understanding of altruistic categories and appeals may help to improve donor recruitment and retention.
- Knowledge of Hepatitis C virus vertical transmission and subsequent pregnancy outcome in virus-positive female blood donors(2022) MENEZES FILHO, Helio Ranes de; MAIA, Ludmila Grego; MACHADO, Soraia Mafra; SILVA, Iasmin Ramos da; ALMEIDA-NETO, Cesar de; SABINO, Ester Cerdeira; WITKIN, Steven S.; MENDES-CORREA, Maria CassiaIntroduction: Hepatitis C virus (HCV) can be vertically transmitted from mother to fetus. We evaluated knowledge about HCV vertical transmission in female blood donors who became pregnant following detection of HCV in their donated blood. Methods: This was a retrospective descriptive study of females seen at a single blood bank in Sao Paulo, Brazil who were diagnosed with HCV infection in their donated blood. HCV-infected donors who subsequently became pregnant were invited to participate through letters or phone calls. Individuals who agreed to participate were interviewed by questionnaire to evaluate their knowledge on HCV vertical transmission. Results: Among 282 HCV-positive female blood donors, 69 reported becoming pregnant after their HCV diagnosis in donated blood. While 24 of these women were successful treated for their infection prior to becoming pregnant, 45 (65.2%) were at risk for vertical HCV transmission either because they had never been treated for HCV, were pregnant before treatment or became pregnant after unsuccessful treatment. Of the 59 women who responded to the question of whether they were informed about the risk of HCV vertical transmission, 58 (98.3%) reported never receiving this information either after obtaining their blood donation results or during their pregnancy. Conclusion: The lack of knowledge of HCV-infected women on the possibility for mother-to-child transmission of this virus highlights the critical need to improve communication about pregnancy-related risks between health professionals and HCV-infected women of childbearing age. (C) 2022 Sociedade Brasileira de Infectologia.
- Validation of a formula predictive of peripheral blood stem cell yield and successful collection in healthy allogeneic donors(2020) ALMEIDA-NETO, Cesar de; ROCHA, Vanderson; MOREIRA, Frederico Rafael; HAMASAKI, Debora Toshie; FARIAS, Madson Correia de; ARRIFANO, Ana Maria; WITKIN, Steven S.; MENDRONE-JUNIOR, AlfredoBackground: An efficient mobilization and collection of peripheral blood stem cells (PBSCs) are crucial to optimize engraftment in the recipient. We aim to validate a formula that predicted CD34(+) cell yield and to describe variables that correlated with high yield mobilization and collection in healthy donors. Methods: We retrospectively analyzed clinical and laboratory data from healthy donors who underwent PBSC collection from 2006 to 2015. The predicted number of collected cells was calculated using the following formula: Total number of CD34(+) (cells x 10(6)/kg) yield = [(peripheral CD34(+) cells/mu L) x (0.43)/recipient body weight (kg)] x total liters processed. Results: We evaluated 338 collections from 307 allogeneic PBSC donors. The predicted versus the observed number of CD34(+) cells/kg collected yielded an r-value of 0.775 (0.726-0.816; p <0.0001). Overall, 55.7% donors had an acceptable mobilization level. Donors with a body weight <67 kg were less likely to yield a satisfactory CD34(+) cell count (OR= 0.44; 95% CI 0.24-0.81), while a white blood cell (WBC) count >= 40 x 10(9)/L (OR = 3.69; 2.11-6.46) and platelet count >= 200 x 10(9)/L (OR= 2.09; 1.26-3.47) on the day of collection predicted a good level of mobilization. Predictors of a CD34+ cell yield/kg of >4 x 106 with only one apheresis session were: circulating CD34(+) cells/mu L >40 (OR= 16; 6.94-36.93), hemoglobin mu 14 g/dL (OR= 3.40; 1.53-7.57), WBC >40 x 10(9)/L (OR= 4.61; 2.10-10.10) on the first collection day, and a positive delta weight between donor and recipient (OR= 3.10; 1.36-7.06). Conclusion: The formula for predicting CD34(+) cell yield is accurate and suggests the optimal length of time for successful leukapheresis. Validation of the predictors of successful mobilization will help to further refine PBSC leukapheresis procedures. (C) 2019 Associacao Brasileira de Hematologia, Hemoterapia e Terapia Celular.
- Influence of unreported HIV prophylaxis on the kinetics of post-blood donation HIV seroconversion(2021) NISHIYA, Anna S.; SALLES, Nanci A.; ALMEIDA-NETO, Cesar de; WITKIN, Steven S.; FERREIRA, Suzete C.; NOGUEIRA, Fatima A. H.; FACINCANI, Tila; ROCHA, Vanderson; MENDRONE-JR, AlfredoBackground In 2020, of 110,000 blood donors screened for HIV exposure two individuals were identified who were viral RNA-positive but seronegative. One of the donors, borderline negative in a pooled screening test for HIV RNA, utilized antiretroviral drugs as post-exposure, pre-donation prophylaxis. The kinetics of subsequent HIV seropositivity in both donors are described. Study Design and Methods Both donors were recalled and interviewed, and blood was obtained at intervals for HIV antibodies and RNA testing. Results One donor used antiretroviral prophylaxis for 30 days due to a relationship with an HIV-positive partner. In follow-up samples, seroconversion was noted at 70 days, and viral RNA was detected at 105 days, after blood donation. In contrast, the other donor seroconverted in <25 days and the appearance and titer of HIV RNA was in accordance with the typical pre-seroconversion window. Conclusion The use of anti-viral prophylaxis by blood donors in the acute phase of HIV infection delays seroconversion. A 6-month deferral in blood donation after HIV prophylaxis, as currently recommended in Brazil, would have been sufficient in this case to mitigate the risk of transfusion-transmitted HIV. Ultimately, improvement in donor compliance with selection procedures for blood donation is needed to optimize blood safety.
- Improved detection of hepatitis C virus-positive blood donors and determination of infection status(2023) NISHIYA, Anna S.; ALMEIDA-NETO, Cesar de; WITKIN, Steven S.; FERREIRA, Suzete C.; SALLES, Nanci A.; NOGUEIRA, Fatima A. H.; OLIVEIRA, Claudia Di Lorenzo; ROCHA, Vanderson; MENDRONE JUNIOR, AlfredoBackground In low-risk populations, variability in the sensitivity of current serological tests for Hepatitis C virus (HCV) blood donor screening may lead to the presence of false-positive results. This contributes to the unnecessary loss of blood donor samples as well as to difficulty in accurate donor counselling. The present study determined the optimal cut-off value of a chemiluminescent immunoassay for identification of HCV-reactive blood donors. Study Design and Methods In a retrospective cross-sectional analysis of 193 973 blood donations, 578 samples that were positive for HCV antibody in a chemiluminescent immunoassay and/or RNA screening tests were identified. Blood from 379 of these positive samples was available for retesting by a second confirmatory HCV immunoassay followed by a receiver operating characteristic (ROC) curve analysis. Donors were also recalled for a new analysis. Results Only 71 (18.7%) blood samples remained HCV-positive upon retesting, while 233 (61.5%) now tested negative and 75 (19.8%) yielding indeterminate results. A signal to cutoff ratio >= 4.32 was determined as the best differential threshold between a positive and negative result, increasing the positive predictive value from 27.3% to 66.7%. Conclusion Using a higher threshold for an HCV-positive blood sample enhances the chemiluminescent immunoassay screening test ' s accuracy and helps to improve donor counselling and notification processes.
- Survival among children and adults treated with granulocyte transfusions: Twenty years' experience at a Brazilian blood center(2022) ALMEIDA-NETO, Cesar de; CORSO, Lucas Machado; BASSOLLI, Lucas; WITKIN, Steven S.; HAMASAKI, Debora Toshie; ALBIERO, Andre Luis; MANANGAO, Caroline Limoeiro; MENDRONE-JUNIOR, Alfredo; ROCHA, VandersonBackground: It remains controversial whether granulocyte transfusions as a supportive treatment improve survival in patients with febrile neutropenia or granulocyte dysfunctions. We describe survival rates subsequent to granulocyte transfusions in pediatric and adults patients treated at a major blood center in Brazil. Material and methods: We retrospectively reviewed the clinical charts of pediatric and adult patients treated with granulocyte transfusions at our institution from January 2000 to October 2019. We assessed demographic characteristics, clinical features, indications for transfusion, units transfused, dose of granulocytes administered and survival rates 30 and 100 days after the initial transfusion. Results: We identified 64 pediatric and 67 adult patients treated with 262 granulocyte transfusions. An optimal dose (> 0.6 x 10(9) granulocytes per kilogram per transfused unit) was available for transfusion in 80.4 % of pediatric patients but in only 19.6 % of adults (p = 0.017). Thirty days after their first granulocyte transfusion, 38 (59.4 %) pediatric and 61 (91 %) adult patients had died. Patients receiving the optimal dose of granulocytes had better survival outcomes, but even among this sub-group, adults were more likely to die than were children either at 30 days (OR = 8.67, 95 %CI 2.69-34.9) or 100 days (OR = 6.27, 95 %CI 1.86-25.9) after their initial granulocyte transfusion. Conclusion: Survival rates following granulocyte transfusion varied by the dose transfused and were higher in children than in adults.