Transfusão de plaquetas: do empirismo ao embasamento científico

Despite major advances in Brazilian blood transfusion therapy with a growing number of scientific publications, an increased number of repeat donors and a decline in serological ineligibility, a lack of conformity in the application of pre-transfusion tests that may compromise transfusion safety is still observed at transfusion agencies in the fringes of the blood transfusion therapy system. Additionally, although high rates of platelet transfusion refractoriness and significant rates of alloimmunization have been demonstrated in the international literature, few Brazilian centers have been concerned with the study of platelet alloimmunization and even fewer centers have evaluated the efficacy of platelet concentrate transfusion. As more than one million Brazilians, including many repeat blood donors, are listed in the National Bone Marrow Donor Registry (Redome), why not grant transfusion therapy services access to the HLA typing of these blood and marrow donors after obtaining their consent? And why not make use of the Redome data to evaluate the HLA compatibility of donors for alloimmunized patients who are candidates for bone marrow transfusion and who have already been typed? These measures, together with the identification of ABO and HPA antigens, will permit a complete assessment of platelet immunology, will guarantee the transfusion safety of this blood component, and will put Brazil at the same level as the so-called developed countries in terms of transfusion medicine

Identification of platelet refractoriness in oncohematologic patients

OBJECTIVES: To identify the occurrence and the causes of platelet refractoriness in oncohematologic patients. INTRODUCTION: Platelet refractoriness (unsatisfactory post-transfusion platelet increment) is a severe problem that impairs the treatment of oncohematologic patients and is not routinely investigated in most Brazilian services. METHODS: Forty-four episodes of platelet concentrate transfusion were evaluated in 16 patients according to the following parameters: corrected count increment, clinical conditions and detection of anti-platelet antibodies by the platelet immunofluorescence test (PIFT) and panel reactive antibodies against human leukocyte antigen class I (PRA-HLA). RESULTS: Of the 16 patients evaluated (median age: 53 years), nine (56%) were women, seven of them with a history of pregnancy. An unsatisfactory increment was observed in 43% of the transfusion events, being more frequent in transfusions of random platelet concentrates (54%). Platelet refractoriness was confirmed in three patients (19%), who presented immunologic and non-immunologic causes. Alloantibodies were identified in eight patients (50%) by the PIFT and in three (19%) by the PRA-HLA. Among alloimmunized patients, nine (64%) had a history of transfusion, and three as a result of pregnancy (43%). Of the former, two were refractory (29%). No significant differences were observed, probably as a result of the small sample size. CONCLUSION: The high rate of unsatisfactory platelet increment, refractoriness and alloimmunization observed support the need to set up protocols for the investigation of this complication in all chronically transfused patients, a fundamental requirement for the guarantee of adequate management

Linfocitopenia T CD4+ associada à sideropenia: relato de caso

Importance of the issue: Idiopathic CD4 T lymphocytopenia is an unusual immune defect in which there is an unexplained deficit of CD4 T cells. This case presents a 39-year-old female patient, with CD4+ T lymphocytopenia, who was not infected with immunosuppressive viruses neither was she subjected to immunosuppressive therapies. Comments: While monitoring the patient, she was found to have very low serum ferritin and, after parenteral iron therapy, there were changes in CD4+ cell levels, indicating that, in this case, lymphocytopenia was secondary to sideropenia. The patient is being kept under strict control of serum iron and periodic immunological evaluation, and she has not showed any clinical and/or laboratory adverse events so far. It is known that iron deficiency is an important factor in the genesis of immunological changes that occur in patients with iron deficiency anemia. It is important to understand the effects of iron deficiency on the immune system due to its high prevalence worldwide. Moreover, it could also help to clarify several cases of idiopathic CD4 lymphocytopenia.Importância da questão: Linfocitopenia T CD4+ idiopática é um defeito imune incomum em que há um déficit inexplicável de células T CD4. Este caso clínico apresenta uma paciente do sexo feminino de 39 anos de idade, com linfocitopenia T CD4+, que não estava infectada por vírus imunossupressores nem foi submetida a terapias imunossupressoras. Comentários: Durante o acompanhamento da paciente, ela apresentou níveis muito baixos de ferritina sérica e, após a terapia parenteral de ferro, houve aumento da quantidade de células CD4+, indicando que, neste caso, linfocitopenia era secundária à sideropenia. A paciente estava sendo mantida sob rigoroso controle de ferro sérico e avaliação imunológica periódica, e não mostrou quaisquer eventos adversos clínicos e/ou laboratoriais até o momento. Com base em mudanças na reatividade imunológica dos pacientes observadas por outros pesquisadores após a suplementação com ferro, é evidente que a deficiência de ferro seria um fator importante na gênese das alterações imunológicas que ocorrem em pacientes com anemia ferropriva. É importante compreender os efeitos da deficiência de ferro no sistema imune, devido à sua elevada prevalência mundial. Essas informações também auxiliariam a esclarecer vários casos de linfocitopenia T CD4+ idiopática

Importância dos testes sorológicos de triagem e confirmatórios na detecção de doadores de sangue infectados pelo vírus da hepatite C

A triagem sorológica de doadores de sangue com baixos índices de prevalência de infecção, como no caso da hepatite C (HCV), gera um percentual considerável de resultados falso-positivos e descarte de bolsas de hemocomponentes freqüentemente não infectados. O objetivo deste estudo foi pesquisar o perfil sorológico e, com base no teste confirmatório, a ocorrência de hepatite C nos doadores com sorologia positiva ou indeterminada do Hemocentro Regional de Uberaba (HRU). Os testes confirmatórios foram realizados por meio da detecção do RNA do HCV no plasma, utilizando-se o método RT-PCR qualitativa. Foram realizadas, no período de 1992 a 2005, 171.027 doações de sangue no HRU, sendo 24,3% de doadores iniciais e 75,7% de retorno. O índice de inaptidão para HCV foi de 0,3% (561 doações), sendo que 53,0% destas eram de doadores iniciais e 47,0% de retorno, com prevalências de 0,5% e 0,2%, respectivamente (pSerological screening of blood donors with low indexes of infection, including hepatitis C virus (HCV), accounts for a substantial percentage of false-positive results with consequent loss of non-infected blood components. The aim of this study was to evaluate the occurrence of hepatitis C using confirmatory tests for blood donors with positive or inconclusive results at Hemocentro Regional de Uberaba (HRU). Confirmatory tests were performed by the detection of HCV RNA in plasma using qualitative RT-PCR. The study was carried out from 1992 to 2005 for 171,027 blood donors, 24.3% first-time and 75.7% repeat donors. The ineligibility rate to HCV was 0.3% (561 donors) with 52.9% of them being first-time donors and 47.0% repeat donors with prevalences of 0.5% and 0.2% respectively (p<0.0001). The rate of inconclusive results was significantly higher among repeat donors (p=0.0214). Ninety-eight samples were subjected to qualitative PCR and only 34.7% (34) had positive results, with a significantly lower rate of positiveness for repeat donors (p = 0.0184) and almost a threefold lower rate of inconclusive results for the same donors. These results showed that, for a large number of donors with positive and inconclusive tests for anti-HCV, the infection was not confirmed. We concluded that serological ineligibility for hepatitis C of donors at HRU was not always associated with the presence of viral infection

A General Latent Class Model for Performance Evaluation of Diagnostic Tests in the Absence of a Gold Standard: An Application to Chagas Disease

We propose a new general Bayesian latent class model for evaluation of the performance of multiple diagnostic tests in situations in which no gold standard test exists based on a computationally intensive approach. The modeling represents an interesting and suitable alternative to models with complex structures that involve the general case of several conditionally independent diagnostic tests, covariates, and strata with different disease prevalences. The technique of stratifying the population according to different disease prevalence rates does not add further marked complexity to the modeling, but it makes the model more flexible and interpretable. To illustrate the general model proposed, we evaluate the performance of six diagnostic screening tests for Chagas disease considering some epidemiological variables. Serology at the time of donation (negative, positive, inconclusive) was considered as a factor of stratification in the model. The general model with stratification of the population performed better in comparison with its concurrents without stratification. The group formed by the testing laboratory Biomanguinhos FIOCRUZ-kit (c-ELISA and rec-ELISA) is the best option in the confirmation process by presenting false-negative rate of 0.0002% from the serial scheme. We are 100% sure that the donor is healthy when these two tests have negative results and he is chagasic when they have positive results

Controle da hemoterapia e da doença de Chagas transfusional: 1988 e 1990

Com o objetivo de atualizar o estudo da situação da hemoterapia no Estado de São Paulo, Brasil foi realizado inquérito em 1990, comparando-o com outro realizado em 1988. Foram pesquisados 79 municípios, sendo que (77,4%) realizavam transfusões de sangue, envolvendo 104 serviços, dos quais 13,5% se utilizavam de sangue proveniente de Hemocentros. Em 1988, o inquérito envolveu 57 municípios, 40 com atividade hemoterápica e 71 serviços, sendo que em 8,5% foi constatada a participação de Hemocentros. O número de doadores, transfusões e prevalência de sorologia positiva para a doença de Chagas foi de, respectivamente: 105.170, 79.544 e 1,24%, enquanto que em 1988 estes números foram: 51.614, 49.211 e 1,52%. Avaliando a triagem sorológica evidenciaram-se 94,2%; 94,2%; 94,2%; 94,3% e 20,2% dos serviços que realizavam, respectivamente, testes sorológicos para doença de Chagas, sífilis, hepatite, HIV e malária, enquanto que em 1988, 69,0%; 70,4%; 67,6%; 63,4% e 16,9% dos serviços empregavam tais testes, respectivamente. Em relação à triagem sorológica específica para doença de Chagas, observou-se que: a reação de fixação do complemento era realizada por 4,9% dos serviços; látex por 4,0%, imunofluorescência indireta 80%; hemaglutinação direta 24%; hemaglutinação indireta 69% e ELISA 59,0%. No inquérito precedente apenas 14,3% dos serviços realizavam teste ELISA, e a fixação do complemento era utilizada em 28,6% dos serviços. Os resultados mostram que os serviços estão utilizando, a cada dia, técnicas mais sensíveis na rotina sorológica. Foi observado ainda que em 1988, 77,6% de todos os serviços estudados realizavam apenas uma técnica para o diagnóstico da doença de Chagas, enquanto que em 1990, 92,9% empregavam duas ou mais diferentes técnicas. Conclui-se que a qualidade da hemoterapia praticada no Estado de São Paulo foi significativamente melhorada nos dois últimos anos.An inquiry with the objective of bringing the study of the hemotherapy situation in the state of S. Paulo, up-to-date was undertaken in 1990 and compared with that carried out in 1988. In 1990 research was undertaken in 62 counties, 48 of which performed blood transfusions through 104 services, with hemocenter participation in 13.5% of these latter. In 1988 the respective figures were 57, 40, 71 and 8.5%. The number of donors and transfusions and prevalence of serological positivity for Chagas' disease were, respectively: 105,170; 79,544 and 1.24%, while in 1988 the corresponding numbers were: 51,614; 49,211 and 1.52%. Evaluating the serological selection it was found that the following percentages of the services performed serological tests: for Chagas' disease (94.2%), siphylis (94.2%), hepatitis (94.2%), HIV (92.3%) and malaria (20.2%) while in 1988 only 69.0%; 70.4%; 67.6%, 63.4% and 16.9%, respectively, of the services utilized these same tests. In respect of the serological trial specific for Chagas' disease the results were: complement fixation-4.9%; latex - 4.0%; indirect immunofluoresce - 80%; direct hemaglutination -24.0%, indirect hemaglutination - 69.0% and ELISA -59.0% of all services. In the preceding inquiry only 14.3% of the services performed the ELISA test, and complement fixation was utilized in 28.6%. The results show that the services are utilizing ever more sensitive techniques in the scrological routine. Further it was observed that in 1988, 77.6% of all the services studied used only one tecnique for the diagnosis of Chagas' disease while in 1990 92.9% utilized two or more different tecniques. It is concluded that the quality of the hemotherapy undertaken in the state of S. Paulo has improved significantly

Sarcoma granulocítico multicêntrico como recidiva de leucemia mieloide aguda

Sarcoma granulocítico (SG) é um tumor sólido extramedular, constituído por células precursoras de granulócitos. É geralmente associado a leucemia mieloide aguda ou raramente a outras desordens mieloproliferativas. O tumor geralmente ocorre precedendo uma leucemia mieloide aguda, durante o seu curso ou após a remissão ter sido alcançada. O prognóstico é pobre e tem como principais modalidades terapêuticas a quimioterapia e a radioterapia. Relata- se um caso de SG multicêntrico, de evolução rápida, com acometimento difuso de pele, mamas, gânglios linfáticos, tecido celular subcutâneo e líquor, em mulher de 45 anos, fora de tratamento para leucemia mieloide aguda e em remissão hematológica há 18 meses. A paciente apresentava dor intensa em membro inferior direito há uma semana e estava em anticoagulação oral há seis meses por trombose venosa profunda neste membro. Diagnosticado o SG, a paciente foi tratada com radioterapia e quimioterapia com boa resposta. Após três meses de seguimento, em vigência do tratamento quimioterápico, evoluiu com recidiva do SG neste membro, associado ao acometimento das mamas e posteriormente do sistema nervoso central, evoluindo para óbito em aplasia e sepses

Performance of six diagnostic tests to screen for Chagas disease in blood banks and prevalence of Trypanosoma cruzi infection among donors with inconclusive serology screening based on the analysis of epidemiological variables

OBJECTIVE: The frequent occurrence of inconclusive serology in blood banks and the absence of a gold standard test for Chagas'disease led us to examine the efficacy of the blood culture test and five commercial tests (ELISA, IIF, HAI, c-ELISA, rec-ELISA) used in screening blood donors for Chagas disease, as well as to investigate the prevalence of Trypanosoma cruzi infection among donors with inconclusive serology screening in respect to some epidemiological variables. METHODS: To obtain estimates of interest we considered a Bayesian latent class model with inclusion of covariates from the logit link. RESULTS: A better performance was observed with some categories of epidemiological variables. In addition, all pairs of tests (excluding the blood culture test) presented as good alternatives for both screening (sensitivity > 99.96% in parallel testing) and for confirmation (specificity > 99.93% in serial testing) of Chagas disease. The prevalence of 13.30% observed in the stratum of donors with inconclusive serology, means that probably most of these are non-reactive serology. In addition, depending on the level of specific epidemiological variables, the absence of infection can be predicted with a probability of 100% in this group from the pairs of tests using parallel testing. CONCLUSION: The epidemiological variables can lead to improved test results and thus assist in the clarification of inconclusive serology screening results. Moreover, all combinations of pairs using the five commercial tests are good alternatives to confirm results

Physical and operational infrastructure of transfusion services of the public blood bank network in the State of Minas Gerais, Brazil, 2007/2008

INTRODUCTION: Within the context of transfusion safety, the immunohematological study of donors and recipients of blood products is currently the most fragile link in the transfusion chain of the public blood bank network of Minas Gerais. OBJECTIVE: The objective of this work was to provide a critical and situational overview of the physical and operational infrastructure of the transfusion services in the state. Method: This was an observational cross-sectional, evidence-based study covering 226 transfusion services; only 19 belong to the Hemominas Foundation and 207 are non-Hemominas transfusion services. The investigation involved the application of questionnaires and red cell panel tests. RESULTS: The results revealed considerable non-compliance with the national law and with the norms of Hemominas. These findings were obtained for the two groups studied; however the frequencies were higher among non-Hemominas transfusion services. CONCLUSION: The study provides information about the situation of the physical and operational infrastructure of transfusion services that may be used to help plan effective measures for improvement and serve as the basis for an evaluation of the impact of future interventions regarding the quality, reliability and safety of transfusions. As primordial factors, we propose compliance with the law, qualified personnel and investment in further qualifications, a review of training methods, and more rigorous inspection of transfusion services. As a suggestion, we propose the establishment of an External Quality Control Program in Immunohematology for the entire network of blood banks in the state and the adoption of the methods presented in this study as a tool to monitor transfusion service performance.INTRODUÇÃO: No contexto da segurança transfusional, o estudo imuno-hematológico do doador e do receptor de hemocomponentes é hoje o elo mais frágil da cadeia transfusional na hemorrede pública de Minas Gerais. OBJETIVO: O objetivo deste trabalho foi traçar panorama crítico e situacional da infraestrutura física e operacional das Agências Transfusionais (ATs) do estado. Método: Estudo observacional transversal, baseado em evidências, abrangeu 226 ATs, sendo 19 próprias da Fundação Hemominas (PH) e 207 não próprias da Hemominas (NPH), com aplicação de questionários e testes de painel de hemácias. RESULTADOS: Os achados do presente estudo mostraram percentuais expressivos de não conformidades com a legislação vigente no país e com as normas estabelecidas pela Hemominas. Estas foram encontradas nos dois grupos estudados, com algumas exceções, apresentando maiores frequências entre as ATs NPH. CONCLUSÃO: O estudo possibilitou o conhecimento da situação da infraestrutura física e operacional das ATs, podendo subsidiar o planejamento de ações efetivas de melhorias, bem como servir de base para avaliar o impacto de futuras intervenções, com vistas à qualidade, confiabilidade e segurança transfusional. Para isto, propôs como fatores primordiais, o cumprimento da legislação vigente, recursos humanos qualificados e investimentos na sua capacitação, revisão das metodologias de treinamento e maior rigor nas verificações e inspeções das ATs. Como sugestão, propõe ainda a criação, pela Hemominas, de Programa de Controle de Qualidade Externo em Imunohematologia para toda hemorrede do estado e adoção da metodologia deste estudo como instrumento de monitoramento da performance das ATs