Serological and Molecular Study of the Duffy Blood Group among Malarial Endemic Region Residents in Brazil

ABSTRACT Background: The atypical chemokine receptor 1 (ACKR1) gene encodes the Duffy blood group antigens in two allelic forms: FY*A (FY*01) and FY*B (FY*02), which define the Fy(a+b-), Fy(a-b+), and Fy(a+b+) phenotypes. FY*BES (FY*02N.01) is a single T to C substitution at nucleotide -67 that prevents the FY*B from being expressed in red blood cells (RBCs). Methods: We evaluated 250 residents from a Brazilian malarial endemic region (RsMR). All individuals were phenotyped for Fya and Fyb antigens and genotyped for FY*A, FY*B, FY*B SE , and FY*B weak alleles. Results: Among the 250 individuals, 209 (83.6%) reported previous malaria infection, and 41 (16.4%) did not. The Fy(a+b+) phenotype was present in 97/250 (38.8%), while the Fy(a-b-) was present in 7/250 (2.8%). The FY*A/FY*B was found in 130/250 (52%) and the FY*A/FY*A in 45/250 (18%). The c.1-67>TC was present, in homozygosity, in 11/250 (4.4%). Among 34 individuals with the Fy(a+b-) and FYA*/FYB* mutations, 4/34 (11.8%) had homozygosity for the c.1-67T>C. One individual presented the Fy(a+b-), FY*A/FY*B, and c.1-67T>C in homozygosis, whereas the other presented the Fy(a+b-), FY*A/FY*A, and c.1-67T>C in heterozygosis. Conclusions: We reported a low prevalence of the Fy(a-b-) in persons who had previously been infected with Plasmodium vivax (67.5%). We observed that 102/141 (72.3%) individuals expressing the Fyb antigen had a P. vivax infection, indicating the importance of the Fyb antigen, silenced by a c.1-67T>C mutation in homozygosis, in preventing the P. vivax infection. We showed that the c.1-67T>C mutation in the FY*A did not silence the FY*A expression on RBCs.

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.

Implications of perioperative allogeneic red blood cell transfusion on the immune-inflammatory response

ABSTRACT Background: The allogeneic transfusion-related immunomodulation (TRIM) may be responsible for an increase in survival of renal transplants but in contrast it could increase the rate of bacterial infections or the recurrence rate of tumors post-operatively. Objective: This review focuses in the implications of perioperative allogeneic transfusions on the immune-inflammatory response of surgical transfused patients. Results: ABTs modify immune functions in recipients including decrease of the number of lymphocytes; decrease the CD4 cells; decrease the CD4/CD8 T-cell ratio; decrease NK cells; and decrease the lymphocyte response to mitogens. TRIM effects may be mediated by allogeneic white cells present in blood products; soluble peptides present in transfused plasma; and/or biologic mediators released into the supernatant of blood units. A recent systematic review and meta-analysis including 36 clinical observational studies (n = 174,036) concluded that perioperative ABTs not only decreased overall survival and reduced colorectal cancer-specific survival. Furthermore ABTs increased the rate of infectious, cardiac, pulmonary and anastomotic complications in colorectal cancer patients undergoing surgery. Conclusions: It has been demonstrated by laboratory tests that TRIM is associated with transfusion recipient immune alterations but its influence in colorectal cancer recurrence after resection remains controversial though may exist. Surgical techniques reducing intraoperative blood loss have limited the number of ABTs perioperatively, however increase in mortality continues to be reported in literature after ABT in colorectal cancer surgery. Poor survival associated to TRIM in colorectal cancer might be due to higher number of allogeneic transfused units and/or prolonged length of blood storage.

Human neutrophil alloantigens systems

Neutrophil alloantigens are involved in a variety of clinical conditions including immune neutropenias, transfusion-related acute lung injury (TRALI), refractoriness to granulocyte transfusions and febrile transfusion reactions. In the last decade, considerable progress has been made in the characterization of the implicated antigens. Currently, seven antigens are assigned to five human neutrophil antigen (HNA) systems. The HNA-1a, HNA-1b and HNA-1c antigens have been identified as polymorphic forms of the neutrophil Fcγ receptor IIIb (CD16b), encoded by three alleles. Recently, the primary structure of the HNA-2a antigen was elucidated and the HNA-2a-bearing glycoprotein was identified as a member of the Ly-6/uPAR superfamily, which has been clustered as CD177. The HNA-3a antigen is located on a 70-95 kDa glycoprotein; however, its molecular basis is still unknown. Finally, the HNA-4a and HNA-5a antigens were found to be caused by single nucleotide mutations in the αM (CD11b) and αL (CD11a) subunits of the leucocyte adhesion molecules (β2 integrins). Molecular and biochemical characterization of neutrophil antigenshave expanded our diagnostic tools by the introduction of genotyping techniques and immunoassays for antibody identification. Further studies in the field of neutrophil immunology will facilitate the prevention and management of transfusion reactions and immune diseases caused by neutrophil antibodies.

Os aloantígenos de neutrófilos estão associados a várias condições clínicas como neutropenias imunes, insuficiência pulmonar relacionada à transfusão (TRALI), refratariedade à transfusão de granulócitos, e reações transfusionais febris. Na última década, foi observado considerável progresso na caracterização dos aloantígenos envolvidos nestas condições clínicas. Atualmente sete antígenos estão incluídos em cinco sistemas de antígenos de neutrófilo humano (HNA). Os antígenos HNA-1a, HNA-1b e HNA-1c foram identificados como formas polimórficas do receptor Fcγ RIIIb (CD16b), codificados por três alelos. Recentemente, a estrutura primária do antígeno HNA-2a foi elucidada e a glicoproteína carreadora do antígeno foi identificada como um membro da superfamília Ly-6/uPARe designada como CD177. O antígeno HNA-3a está localizadoem uma glicoproteína de 70-90 kDa, entretanto sua base molecular ainda é desconhecida. Finalmente, os antígenos HNA-4ae HNA-5a são resultantes de mutações de um único nucleotídeo nas subunidades αM (CD11b) and αL (CD11a) das moléculas de adesão de leucócitos (β2 integrinas). A caracterização molecular e bioquímica dos antígenos neutrofílicos permitiu a expansão das ferramentas diagnósticas pela introdução de técnicas de genotipagem e imunoensaios para a identificação de anticorpos. Novos estudos envolvendo a imunologia de granulócitos serão de grande valor para a prevenção e tratamento de reações transfusionais e doenças imunes causadas por aloanticorpos de neutrófilos.

Anemia hemolítica auto-imune e outras manifestações imunes da leucemia linfocítica crônica / Autoimmune hemolytic anemia and other autoimmune diseases related to chronic lymphocytic leukemia

A leucemia linfocítica crônica (LLC) é freqüentemente associada a manifestações auto-imunes principalmente relacionadas às células do sistema hematopoético causando anemia hemolítica auto-imune (AHAI), púrpura trombocitopênica imune (PTI), aplasia pura de série vermelha (APSV), e neutropenia imune. A LLC é diagnosticada em até 15 por cento dos pacientes com AHAI, e em cerca de 50 por cento dos pacientes com AHAI secundária a doença maligna. A PTI ocorre em 2 por cento, e a APSV em 1 por cento dos pacientes com LLC. Prednisona é o tratamento inicial de escolha para a citopenia imune associada à LLC. Para cerca de 60 por cento dos pacientes que apresentam recidiva da manifestação auto-imune tem sido utilizada esplenectomia, imunoglobulina endovenosa, ou ciclosporina. Embora as evidências sobre fisiopatologia sejam limitadas, os mecanismos fisiopatológicos da auto-imunidade na LLC estão relacionados à atividade dos linfócitos B leucêmicos que atuam como células apresentadoras de antígeno aberrantes, e são eficientes em processar e apresentar proteínas da membrana de hemácias e de plaquetas às células TH auto-reativas. Linfócitos TH específicos para certos auto-antígenos podem escapar de mecanismos de controle de auto-tolerância, e, se ativados, podem causar doença auto-imune. O diagnóstico de AHAI contra-indica o uso de fludarabina em pacientes com LLC, pois esse análogo da purina tem sido associado ao desenvolvimento de AHAI grave e fatal, com risco consideravelmente mais alto para pacientes mais imunossuprimidos devido a vários tratamentos anteriores.

Chronic lymphocytic leukemia (CLL) is frequently associated with autoimmune diseases directed against hematopoietic cells, including autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), pure red cell aplasia (PRCA), and immune neutropenia. CLL represents the diagnosis in up to 15 percent of the patients with AIHA, and in 50 percent of the patients with AIHA secondary to malignancy. ITP occurs in 2 percent and PRCA in about 1 percent of all CLL patients. Prednisone is the first-line treatment for immune cytopenia related to CLL. About 60 percent of patients relapse when treatment is stopped therefore splenectomy, intravenous immunoglobulin, or cyclosporine are reasonable second-line treatments. Although the data on pathophysiology are very limited, it appears that the autoimmune mechanisms are related to the activity of the leukemic B lymphocytes that act as aberrant antigen-presenting cells, and are effective in processing and presenting proteins derived from red cells or platelets to auto-reactive TH cells. TH cells specific for certain auto-antigens escape from control mechanisms and when activated may initiate auto-immune disease. Patients with AIHA secondary to CLL should not receive fludarabine because there is an increased frequency of severe and fatal AIHA in patients treated with purine nucleoside analogues. Patients who are more immunosuppressed due to several previous treatments are at higher risk for developing this auto-immune complication.

Reação transfusional hiper-hemolítica em pacientes portadores de anemia falciforme: relato de dois casos / Hyper-hemolytic transfusional reaction in sickle cell patients: two case reports

O caráter crônico da anemia, nos pacientes portadores de anemia falciforme, associado à maior capacidade de liberação de oxigênio pela Hb S, faz com que sejam pouco sintomáticos em relação à anemia e não necessitem de forma rotineira de transfusão de hemácias. Contudo, na vigência de complicações agudas, a queda adicional da hemoglobina pode precipitar descompensação da função cardio-respiratória e colocar em risco a vida do paciente, tornando a transfusão de sangue um recurso terapêutico de grande importância. Em virtude da elevada freqüência de transfusões a que esses pacientes são submetidos, é de fundamental importância o conhecimento dos principais riscos e o diagnóstico adequado das complicações decorrentes da terapia transfusional. Uma forma atípica de reação transfusional, denominada reação transfusional hiperhemolítica, foi descrita recentemente em pacientes com anemia falciforme após transfusão de hemácias aparentemente compatíveis. (4,5,6,7) Nesta condição, transfusões ulteriores podem exacerbar o quadro hemolítico e colocar em risco a vida do paciente. Os mecanismos patofisiológicos exatos dessa entidade ainda não são bem conhecidos e o tratamento consiste na suspensão da transfusão, corticoterapia e/ou administração de imunoglobulina. O objetivo deste trabalho é apresentar o relato de dois casos de reação transfusional hiperhemolítica em pacientes portadores de anemia falciforme.

The chronic character of sickle cell anemia associated with the greater capacity to liberate oxygen by the Hb S, results in patients exhibiting few symptoms in relation to the anemia and they do not require regular hemacias transfusions. Nevertheless, in the face of acute complications, the additional drop in hemoglobin can precipitate an imbalance in the cardio-respiratory function and put the life of the patient at risk, making blood transfusion therapy of utmost importance.In the light of the increased frequency of transfusions to which these patients are submitted, knowledge of the main risks and an adequate diagnosis of the complications caused by transfusional therapy are of fundamental importance.An atypical form of transfusional reaction, denominated hyperhemolytic transfusional reaction was recently described in sickle cell anemia patients after the transfusion of apparently compatible hemacias.In this case, previous conditions can exacerbate the hemolytic condition and put the life of the patient at risk. The pathophysiological conditions of this disease are not yet understood well and the treatment consists of suspending transfusions, corticoid therapy and / or administration of immunoglobulin.The aim of this work is o present two case reports of hyperhemolytic transfusional reaction in sickle cell anemia patients.

The application of latent class analysis for diagnostic test validation of chronic Trypanosoma cruzi infection in blood donors

The main strategy to prevent transfusion-associated Chagas disease is the identification of T. cruzi-infected blood donors by serological screening tests, however there is no perfect serological gold standard. We evaluated an enzyme immunoassay (EIA), an indirect hemaglutination (IHA), and an indirect immunofluorescence (IIF) test for detecting T. cruzi antibodies in Brazilian blood donors. The results were submitted to latent class analysis, and a radioimmunopreciptation (RIPA) test was performed on repeatedly positive samples. Among 1951 donors, 11 (0.56) were positive by EIA, 6 (0.31) by IHA and 16 (0.82) by IIF. Six samples were positive with all tests, while 4 reacted with EIA and IIF. The RIPA was positive in 6 (75.0), 7 (66.6), and 4 (54.0) samples reacting by the EIA, IHA and IIF tests, respectively. The latent class model detected a high sensitivity rate (100) for the EIA and IIF, and a specificity rate of 99.95 and 99.69 for the EIA and IIF tests, respectively. The probability of being case according to the model was 99.92 when both EIA and IIF were positive, and 100 for the association of EIA, IIF, and IHA.

Púrpura trombocitopênica aloimune neonatal: caracterizaçäo de aloanticorpo plaquetário anti-HPA-1A (Anti-PIA1) por radioimunoprecipitaçäo indireta / Alloimmune neonatal thrombocytopenic purpura: characterization of platelet alloantibody anti-HPA-1A (Anti-PIA1) by indirect radioimmunoprecipitation

A púrpura trombocitopênica alo-imune neonatal (PTAN) é uma doença grave na qual a hemorragia cerebral pode ser fatal ou levar a seqüelas cerebrais permanentes. Similarmente, à doença hemolítica do recém-nascido (RN), a PTAN ocorre devido a aloimunizaçäo materna por um alo-antigeno incompatível presente nas plaquetas fetais. A apresentaçäo clínica é de púrpura generalizada acompanhada de hemorragia gastrointestinal, urinária, e/ou intracranial. O alo-antigeno HPA-1 (PL(A)) é responsável por cerca de 70-80 por cento dos casos de PTAN. Nesse estudo, os autores descrevem o caso de uma gestante que deu a luz a um RN com plaquetopenia acentuada devido a trombocitopenia aloimune. A contagem plaquetária da mae e do RN era 173 x 10(9)/L e 15 x 10(9)/L, respectivamente. O estudo sorológico realizado com a técnica de radioimunoprecipitaçäo indireta demonstrou forte reatividade do soro materno com o complexo glicoprotético GPIIb/IIIa em plaquetas PI(A1)-positivas de doador normal. Assim, o soro materno continha forte atividade anti-HPA-1a (anti-PI(A1)). O RN foi tratado com corticosteróides e gamaglobulina intravenosa. Após o tratamento, o RN teve alta hospitalar com contagem plaquetária elevada para 70 x 10(9)/L.

Síndrome de Budd-Chiari associada a policitemia "vera": indicaçäo de transplante hepático ou derivaçäo venosa? / Budd-Chiari syndrome associated to polycythemia vera: indication for liver transplantation or venous shunts?

É apresentado um caso de síndrome de Budd-Chiari associado a policitemia vera, em que foi indicado o transplante ortóptico do fígado. Após revisao da literatura acerca da etiologia e terapêutica dessa associaçao, discutem-se os fatores que devem influenciar a decisao a ser tomada entre um transplante de fígado ou uma derivaçao venosa.