Hypocoagulability in severe yellow fever infection is associated with bleeding: results from a cohort study.

Background: Severe yellow fever infection (YFI) may be complicated by a hemorrhagic diathesis. However, the hemostasis profile of YFI has rarely been reported. Objectives: The aim of this study was to characterize the hemostatic features of YFI by using a rotational thromboelastometry (ROTEM). Methods: We evaluated clinical, laboratory, and ROTEM parameters in adults with severe YFI and their correlation with hemostatic variables according to bleeding and death. Results: A total of 35 patients were included (median age, 49 years). ROTEM was performed in 22 patients, of whom 21 (96%) presented bleeding and 4 (18%) died. All patients who died had major bleeding. Patients who died presented prolonged clotting time (CT; median, 2326 seconds; IQR, 1898-2986 seconds) and reduced alpha angle (median, 12°; IQR, 12°-15°) in comparison with patients who had minor (median CT, 644 seconds; IQR, 552-845 seconds and alpha angle, 47°; IQR, 28°-65°) and major (median CT, 719 seconds; IQR, 368-1114 seconds and alpha angle, 43°; IQR, 32°-64°) bleeding who survived. In patients who had bleeding, CT showed a strong negative correlation with factor (F)V (r = -.68), FIX (r = -.84), and FX (r = -.63) as well as alpha angle showed a strong negative correlation with FIX (r = -.92). In patients who died, the correlations were even stronger. A total of 19/21 (90%) patients presented hypocoagulability assessed by ROTEM. Conclusion: Hypocoagulabitity is the hallmark of the bleeding diathesis of severe YFI. Abnormal CT and alpha angle associated with death and could be used as potential predictors of adverse outcome in severe YFI.

Deficiency of coagulation factors is associated with the bleeding diathesis of severe yellow fever.

Yellow fever (YF) is an acute tropical infectious disease caused by an arbovirus and can manifest as a classic hemorrhagic fever. The mechanism of the bleeding diathesis in YF is not well understood. We assessed clinical and laboratory data (including a panel of coagulation tests) from 46 patients with moderate (M) and severe (S) YF admitted to a local hospital between January 2018 and April 2018. Among 46 patients, 34 had SYF of whom 12 (35%) patients died. A total of 21 (45%) patients developed some type of bleeding manifestation and 15 (32%) presented severe bleeding. Patients with SYF had more severe thrombocytopenia (p = 0.001); prolonged activated partial thromboplastin time (aPTT) and thrombin time (TT) (p = 0.03 and p = 0.005, respectively); reduced plasma levels of coagulation factor (F) II (p < 0.01), FIX (p = 0.01), and FX (p = 0.04); and D-dimer levels almost 10 times higher (p < 0.01) when compared with patients with MYF. Patients who died had more bleeding (p = 0.03), more major bleeding (p = 0.03), prolonged international normalized ratio (INR) and aPTT (p = 0.003 and p = 0.002, respectively), as well as lower activity of FII (p = 0.02), FV (p = 0.001), FVII (p = 0.005), FIX (p = 0.01), and protein C (p = 0.01) than the ones who survived. FVIII levels were either normal or increased in all patients studied. Our results suggest that the bleeding diathesis of SYF is associated with the deficiency of coagulation factors produced by the liver. Prolonged INR and aPTT and reduced FII, FV, FVII, FIX, and protein C were associated with death.

Chagas disease: Performance analysis of immunodiagnostic tests anti-Trypanosoma cruzi in blood donors with inconclusive screening results

ABSTRACT Background: The screening of Trypanosoma cruzi-infected blood donors using two serological techniques frequently leads to conflicting results. This fact prompted us to evaluate the diagnostic performance of four "in-house" immunodiagnostic tests and two commercially available enzyme-linked immunosorbent assays (ELISAs). Material and Methods: One hundred and seventy-nine blood donors, whose screening for Chagas disease was doubtful, underwent three in-house ELISAs, one in-house immunoblotting test (TESA-blot), and two commercial ELISAs (bioMérieux and Wiener) in an attempt to define the presence or absence of infection. Simultaneously, 29 donors with previous positive results from three conventional serological tests and 30 donors with constant negative results were evaluated. Results: The ELISA-Wiener showed the highest rate in sensitivity (98.92%) and the ELISA-bioMérieux, the highest specificity (99.45%), followed by the TESA-blot, which showed superior performance, with lower false-negative (2.18%) and false-positive (1.12%) rates. In series, the combination composed of the TESA-blot and ELISA-bioMérieux showed slightly superior performance, with trifunctional protein deficiency (TFP) = 0.01%. Conclusion: Our study confirms the high sensitivity and specificity of commercial kits. To confirm the presence or absence of T. cruzi infection, the combination of TESA-blot and ELISA-bioMérieux may be suggested as the best alternative. Individually, the TESA-blot performed the closest to the gold standard; however, it is not commercially available.

Chagas disease: Performance analysis of immunodiagnostic tests anti-Trypanosoma cruzi in blood donors with inconclusive screening results.

BACKGROUND: The screening ofTrypanosoma cruzi-infected blood donors using two serological techniques frequently leads to conflicting results. This fact prompted us to evaluate the diagnostic performance of four "in-house" immunodiagnostic tests and two commercially available enzyme-linked immunosorbent assays (ELISAs). MATERIAL AND METHODS: One hundred and seventy-nine blood donors, whose screening for Chagas disease was doubtful, underwent three in-house ELISAs, one in-house immunoblotting test (TESA-blot), and two commercial ELISAs (bioMérieux and Wiener) in an attempt to define the presence or absence of infection. Simultaneously, 29 donors with previous positive results from three conventional serological tests and 30 donors with constant negative results were evaluated. RESULTS: The ELISA-Wiener showed the highest rate in sensitivity (98.92%) and the ELISA-bioMérieux, the highest specificity (99.45%), followed by the TESA-blot, which showed superior performance, with lower false-negative (2.18%) and false-positive (1.12%) rates. In series, the combination composed of the TESA-blot and ELISA-bioMérieux showed slightly superior performance, with trifunctional protein deficiency (TFP)=0.01%. CONCLUSION: Our study confirms the high sensitivity and specificity of commercial kits. To confirm the presence or absence of T. cruzi infection, the combination of TESA-blot and ELISA-bioMérieux may be suggested as the best alternative. Individually, the TESA-blot performed the closest to the gold standard; however, it is not commercially available.

A blockage monoclonal antibody protocol as an alternative strategy to avoid anti-CD38 interference in immunohematological testing.

BACKGROUND: As CD38 is expressed on red blood cells (RBCs), the plasma of patients on daratumumab (DARA) reacts with the panel cells of pretransfusion tests, masking underlying alloantibodies. The treatment of RBCs with dithiothreitol (DTT) is the most disseminated method to overcome DARA effect on immunohematological tests, but it hampers the identification of potentially harmful antibodies. Our goal was to validate a new strategy, the blockage monoclonal antibody protocol (BMAP), to mitigate the DARA interference on RBCs using anti-CD38 and antihuman globulin. METHODS: Samples of patients receiving DARA were included in the study. Sera were tested using both DTT- and BMAP-treated RBCs, which comprised three steps: 1) titration of monoclonal anti-CD38, 2) treatment of RBCs obtained from donors with anti-CD38, and 3) blockage of anti-CD38-adsorbed RBCs with antihuman globulin. RESULTS: Twenty patients were included in the study. Donor RBCs were treated with anti-CD38 and successfully blocked with antihuman globulin. In 19 patients, DARA-mediated agglutination was eliminated using both DTT- and BMAP-treated RBCs. In one patient, agglutination persisted when tested against the BMAP-treated RBCs, and alloantibodies were identified. Patient samples were mixed with commercial anti-D, -C, -e, -K, -Jka, -Kpb and tested against antigen-positive BMAP-treated RBCs, resulting in detection of these antibodies. CONCLUSION: This study validated a new strategy to minimize the interference of DARA on immunohematological tests. The protocol preserves the integrity of RBC antigens, permitting the detection of antibodies from all blood group systems. The BMAP has potential use in other situations where specific antibodies may interfere with pretransfusion screening.

Evaluation of cross reactivity between Trypanosoma cruzi and Leishmania infantum in serologically ineligible blood donors due to chagas diseas

Inconclusive serological screening for Trypanosoma cruzi has been a problem for blood banks. This study examined the performance of serological techniques for Chagas disease in reagent samples from blood bank screenings and verified the possibilities of cross reactivity with visceral leishmaniasis. 68 samples of reagent donors tested with ELISA for Chagas disease were evaluated by other techniques and for the detection of anti-Leishmania antibodies. Four donors (5.9%) with positive results for T. cruzi were positive for ELISA Kalazar Detect (visceral leishmaniasis),three of which were confirmed by Western blot. This study confirms the specificity of the tests for Chagas disease in blood banks and reinforces the urgent adoption of measures to assess the real risk of transfusion transmission of visceral leishmaniasis

Analysis of donor deferral at three blood centers in Brazil.

BACKGROUND: The safety of the blood supply is ensured through several procedures from donor selection to testing of donated units. Examination of the donor deferrals at different centers provides insights into the role that deferrals play in transfusion safety. STUDY DESIGN AND METHODS: A cross-sectional descriptive study of prospective allogeneic blood donors at three large blood centers located in São Paulo, Belo Horizonte, and Recife, Brazil, from August 2007 to December 2009 was conducted. Deferrals were grouped into similar categories across the centers, and within each center frequencies out of all presentations were determined. RESULTS: Of 963,519 prospective blood donors at the three centers, 746,653 (77.5%) were accepted and 216,866 (22.5%) were deferred. Belo Horizonte had the highest overall deferral proportion of 27%, followed by Recife (23%) and São Paulo (19%). Females were more likely to be deferred than males (30% vs. 18%, respectively). The three most common deferral reasons were low hematocrit or hemoglobin, medical diagnoses, and higher-risk behavior. CONCLUSION: The types and frequencies of deferral vary substantially among the three blood centers. Factors that may explain the differences include demographic characteristics, the order in which health history and vital signs are taken, the staff training, and the way deferrals are coded by the centers among other policies. The results indicate that blood donor deferral in Brazil has regional aspects that should be considered when national policies are developed.

Prevalence of serologic markers for hepatitis B and C viruses in Brazilian blood donors and incidence and residual risk of transfusion transmission of hepatitis C virus.

BACKGROUND: We evaluate the current prevalence of serologic markers for hepatitis B virus (HBV) and hepatitis C virus (HCV) in blood donors and estimated HCV incidence and residual transfusion-transmitted risk at three large Brazilian blood centers. STUDY DESIGN AND METHODS: Data on whole blood and platelet donations were collected from January through December 2007, analyzed by center; donor type; age; sex; donation status; and serologic results for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and anti-HCV. HBV and HCV prevalence rates were calculated for all first-time donations. HCV incidence was derived including interdonation intervals that preceded first repeat donations given during the study, and HCV residual risk was estimated for transfusions derived from repeat donors. RESULTS: There were 307,354 donations in 2007. Overall prevalence of concordant HBsAg and anti-HBc reactivity was 289 per 100,000 donations and of anti-HCV confirmed reactivity 191 per 100,000 donations. There were significant associations between older age and hepatitis markers, especially for HCV. HCV incidence was 3.11 (95% confidence interval, 0.77-7.03) per 100,000 person-years, and residual risk of HCV window-phase infections was estimated at 5.0 per million units transfused. CONCLUSION: Improvement in donor selection, socioeconomic conditions, and preventive measures, implemented over time, may have helped to decrease prevalence of HBV and HCV, relative to previous reports. Incidence and residual risk of HCV are also diminishing. Ongoing monitoring of HBV and HCV markers among Brazilian blood donors should help guide improved recruitment procedures, donor selection, laboratory screening, and counseling strategies.

Performance of parallel screening of Brazilian blood donors with two human immunodeficiency virus immunoassays: implications for sequential immunoassay testing algorithms in other countries.

BACKGROUND: In Brazil it is mandatory to screen donors for human immunodeficiency virus (HIV) antibodies using two immunoassays (IAs) in parallel. Confirmatory testing is performed only on reactive donors who return for counseling. The goal of this analysis was to determine if concordant IA reactivity accurately predicts infection and can be used for HIV incidence and/or prevalence analyses. STUDY DESIGN AND METHODS: We reviewed HIV screening and confirmatory results obtained for 307,407 donations in the first year of the REDS-II study in Brazil (2007) and for 2,304,755 donations collected from 1996 to 2006 in one of the REDS-II sites (São Paulo, Brazil). RESULTS: In the São Paulo site, 11,410 (0.50%) HIV IA-reactive donations were discarded, but only 2095 (0.09%) were reactive to both IAs. Western blot was positive on 1002 (48%) dual-IA-reactive donors who returned for counseling. Only four HIV-infected donors were detected who had been missed at screening by one of the IAs; all occurred before 2002. The positive predictive value (PPV) of dual-IA reactivity varied from 45.8 to 100%, with 80% to 90% PPVs when using IAs from different manufacturers. If both assays yielded signal-to-cutoff (S/C) values of 3.0 or more, PPVs ranged from 91% to 99%, with approximately 99% sensitivity for true HIV seropositivity. CONCLUSION: Parallel testing of all donations has limited efficacy when highly sensitive IAs are used. Reactivity by two sequential IAs is useful for prevalence studies if the assays are from different manufacturers and especially if high S/C values are considered.

Evaluation of the use of real-time PCR for human T cell lymphotropic virus 1 and 2 as a confirmatory test in screening for blood donors.

INTRODUCTION: HTLV-1/2 screening among blood donors commonly utilizes an enzyme-linked immunosorbent assay (EIA), followed by a confirmatory method such as Western blot (WB) if the EIA is positive. However, this algorithm yields a high rate of inconclusive results, and is expensive. METHODS: Two qualitative real-time PCR assays were developed to detect HTLV-1 and 2, and a total of 318 samples were tested (152 blood donors, 108 asymptomatic carriers, 26 HAM/TSP patients and 30 seronegative individuals). RESULTS: The sensitivity and specificity of PCR in comparison with WB results were 99.4% and 98.5%, respectively. PCR tests were more efficient for identifying the virus type, detecting HTLV-2 infection and defining inconclusive cases. CONCLUSIONS: Because real-time PCR is sensitive and practical and costs much less than WB, this technique can be used as a confirmatory test for HTLV in blood banks, as a replacement for WB.

Evaluation of the use of real-time PCR for human T cell lymphotropic virus 1 and 2 as a confirmatory test in screening for blood donors / Análise do uso da PCR em tempo real para HTLV-1 e 2 como teste confirmatório na triagem de doadores de sangue

INTRODUCTION: HTLV-1/2 screening among blood donors commonly utilizes an enzyme-linked immunosorbent assay (EIA), followed by a confirmatory method such as Western blot (WB) if the EIA is positive. However, this algorithm yields a high rate of inconclusive results, and is expensive. METHODS: Two qualitative real-time PCR assays were developed to detect HTLV-1 and 2, and a total of 318 samples were tested (152 blood donors, 108 asymptomatic carriers, 26 HAM/TSP patients and 30 seronegative individuals). RESULTS: The sensitivity and specificity of PCR in comparison with WB results were 99.4 percent and 98.5 percent, respectively. PCR tests were more efficient for identifying the virus type, detecting HTLV-2 infection and defining inconclusive cases. CONCLUSIONS: Because real-time PCR is sensitive and practical and costs much less than WB, this technique can be used as a confirmatory test for HTLV in blood banks, as a replacement for WB.

INTRODUÇÃO: A triagem para HTLV-1/2 em doadores de sangue geralmente utiliza imunoensaio enzimático, seguido de um método confirmatório como Western blot quando o EIA é positivo, mas este algoritmo mostra alta taxa de resultados inconclusivos, e elevado custo. MÉTODOS: Dois ensaios qualitativos de PCR em tempo real foram desenvolvidos para detectar HTLV-1 e 2 e um total de 318 amostras foram testadas por PCR (152 de doadores de sangue, 108 de portadores assintomáticos, 26 de pacientes HAM/TSP e 30 de indivíduos soronegativos). RESULTADOS: A sensibilidade e especificidade das PCR em relação aos resultados de WB foram de 99,4 por cento e 98,5 por cento, respectivamente. As PCR foram mais eficientes em identificar o tipo viral, a infecção pelo HTLV-2 e úteis para definir casos inconclusivos. CONCLUSÕES: Por serem sensíveis, práticas e de custo muito inferior ao do WB, as técnicas de PCR em tempo real podem ser usadas como teste confirmatório do HTLV em bancos de sangue, em substituição ao WB.