José O. Bordin

Maternal immunization to Gov system alloantigens on human platelets

BACKGROUND: Immunization to platelet alloantigens can occur during pregnancy or after the transfusion of blood components. Platelet alloantibodies can cause neonatal alloimmune thrombocytopenia and posttransfusion purpura. Transfusion‐induced alloimmunization to a novel platelet alloantigen system, Gov, expressed on the 175‐kDa glycosyl phosphatidylinositol‐anchored platelet glycoprotein, CD109, was previously described. This report describes three unrelated patients who were alloimmunized to Gov(a) or Gov(b) during pregnancy. STUDY DESIGN AND METHODS: Platelets were typed by using radioimmunoprecipitation for HPA‐1a, −3a, −5a, −5b, Gov(a), and Gov(b) and by polymerase chain reaction‐restriction fragment length polymorphism for HPA‐1a, −1b, −3a, and −3b. Maternal sera were screened for platelet antibodies by using radioimmunoprecipitation and the antigen capture assay. RESULTS: Patients 1 and 2 were investigated after the diagnosis of neonatal alloimmune thrombocytopenia in their children, and alloantibodies specific for Gov(b) and Gov(a), respectively, were detected in maternal serum. Serum from patient 3, who had mild idiopathic thrombocytopenia purpura with no detectable autoantibody, was found to contain alloantibodies to Gov(b) and to HPA‐ 5b, presumably as a result of immunization during pregnancy. Platelet typings confirmed that the patients were at risk for alloimmunization to the respective antigen. CONCLUSION: This report of three cases of maternal alloimmunization to antigens in the Gov system indicates that immunization can occur via placental transfer of antigen and that Gov system alloantibodies may be associated with neonatal alloimmune thrombocytopenia.

Allelic polymorphisms of human Fcγ receptor IIa and Fcγ receptor IIIb among distinct groups in Brazil

BACKGROUND: The FcγRIIA gene is expressed in two polymorphic forms, R131 and H131, which differ by the replacement of histidine by arginine at position 131. The FCGR3B (FcγRIIIB) gene exists in two allelic isoforms, known as FCGR3B1 (FcγRIIIB‐NA1) and FCGR3B2 (FcγRIIIB‐NA2), which differ in nucleotides 141, 147, 227, 277, and 349. An additional polymorphism is the SH antigen that is associated with the FCGR3B3 (FcγRIIIB‐SH) allele.

Impact of using different laboratory assays to detect human leukocyte antigen antibodies in female blood donors

BACKGROUND: HLA antibodies passively transferred to transfused recipients may cause transfusion reactions such as transfusion‐related acute lung injury (TRALI), but in many of the reported TRALI incidents, no white blood cell antibodies have been identified. We investigated whether a higher number of anti‐HLA would be detected in donors plasma by using a method with potential higher sensitivity rate.

RBC-associated IgG in patients with visceral leishmaniasis (kala-azar): a prospective analysis.

BACKGROUND: Despite the fact that anemia is one of the most striking clinical features of visceral leishmaniasis (kala‐azar), the factors involved in its pathogenesis are not fully understood. Although the cause of the anemia seen in these patients is often multifactorial, sequestration and destruction of the RBCs in the enlarged spleen, immune mechanisms, and alterations in RBC membrane permeability have been implicated.

Myonecrosis in sickle cell anemia: case report and review of the literature.

Vascular occlusion is responsible for most of the severe complications of sickle cell anemia (SCA). The involvement of muscle and fascia is uncommon in SCA, but myonecrosis may occur in SCA crisis. The data accumulated in the literature is limited to only a few reports describing mainly adult patients presenting with severe muscular pain. We report a rare case of sickle myonecrosis and secondary involvement of an associated joint after a severe painful crisis in the left thigh.

Hemolytic anemia after kidney transplantation: a prospective analysis

BACKGROUND: Hemolysis may occur in 9% to 40% of patients after solid organ transplantation and be caused by the passenger lymphocyte syndrome (PLS).

Expression of Fas and Fas ligand on spleen T cells of experimental animals after unmodified or leukoreduced allogeneic blood transfusions.

BACKGROUND: The clonal deletion seen in recipients of allogeneic blood transfusion (ABT) refers to the removal of lymphocytes that promote the clearance of transfused alloantigens. Interactions between Fas (CD95) and FasL (CD95L) are involved in the clonal deletion of T cells and in the down regulation of the cytotoxic T‐cell activity.

Bacterial infection-associated improvement of platelet counts in two patients with chronic and unresponsive idiopathic thrombocytopenic purpura with normal platelet survival studies

Summary. Approximately 20% of adult patients with idiopathic thrombocytopenic purpura (FTP) do not respond to splenectomy and require alternative therapies to achieve a clinically safe platelet count. A small percentage of these patients have very refractory disease and are either unresponsive or poorly responsive to almost any therapy. In this report we describe two patients with chronic and unresponsive ITP with normal platelet survivals. Neither patient had responded to a large variety of treatments including corticosteroids, splenectomy, IVIgG, anti‐D, chemotherapy, and ascorbic acid. However, both had a rapid, but short‐lived, rise in their platelet count following a bacterial infection. One patient had a rise in platelet count for 6 months following the acute episode of bacteraemia. The second patient had a shorter response of 1 week. It is possible that these two patients represent a subset of patients with ITP who may benefit from cytokine therapy.

Molecular Basis of KELnull Phenotype in Brazilians

Background: KELnull (K₀) persons can produce clinically significant anti-KEL5 antibody after transfusion and/or pregnancy, requiring K₀ blood transfusion when indicated. 37 K₀ alleles have been reported in studies over different populations, but none in Amerindian-Caucasian descendants from South America. The aim of this study was to identify the molecular basis of K₀ phenotype in Brazilians. Methods: We investigated three K₀ samples from different Brazilian blood banks (Recife, Manaus, and Vila Velha) in women with anti-KEL5. KEL antigen typing was performed by serologic techniques, and the K₀ status was confirmed by flow cytometry. PCR-RFLP and DNA sequencing of the KEL coding and exon-intron regions were also performed. Results: RBCs of the 3 patients were phenotyped as KEL:-1,-2,-3,-4,-7. The 3 patients had the same KEL*02/02 genotype and were negative for KEL*02.03 and KEL*02.06 alleles. The Recife K₀ patient was homozygous for IVS16 + 1g>a mutation (KEL*02N.31 allele). The flow cytometry with anti-KEL1, anti-KEL2, anti-KEL3, anti-KEL4, and anti-CD238 confirmed the K₀ phenotype. In addition, we found the c.1042C>T mutation (KEL*02N.04 allele) in both the Manaus K₀ and the Vila Velha K₀ patients. Conclusion: This report represents the first study of K₀ molecular basis performed in Amerindian-Caucasian descendants from South America.

Antibodies to human neutrophil antigen HNA-3b implicated in cases of neonatal alloimmune neutropenia: ANTI-HNA-3B IMPLICATED IN CASES OF NAIN

Neonatal alloimmune neutropenia results from maternal alloimmunization to human neutrophil antigens. The alloantibodies involved in neonatal alloimmune neutropenia are against human neutrophil antigens HNA‐1a, HNA‐1b, HNA‐1c, HNA‐1d, HNA‐2, HNA‐3a, HNA‐4a, HNA‐4b, and HNA‐5a; however, to date, antibodies specific to HNA‐3b have not been reported.