RESUMO
Blood transfusion may lead to the manifestation of anti-HLA and platelet-specific antibodies that may in turn bring about different problems like platelet refractoriness. It appears that the study of antibodies against HLA-Class I and platelet-specific antigens are useful for the selection and success of the appropriate treatment protocol. The aim of this study was to detect anti-HLA and anti-platelet-specific antibodies by flowcytometry in patients with hematologic disorders [including Acute Leukemia, Aplastic Anemia] and patients with ITP. In this descriptive study, anti-HLA and platelet-specific antibodies were detected by flowcytometric technique, using 62 sera drawn from patients with different hematological disorders who showed a poor response to platelet transfusion and 20 from patients with ITP. The results of anti-HLA antibodies were then compared by Panel Reactive Antibodies [PRA]. Our results showed 44 [53.7%] out of 82 patients had anti-HLA Class-I antibodies in their sera. The frequency of each antibody isotype was found to be as follows: IgM [51.2%], IgG [32.9%] and IgA [1.2%]. 36 [43.9%] out of 82 patients had platelet specific antibodies and the frequency of each antibody isotype was found to be as follows: IgM [40.2%], IgG [30.5%] and IgA [12.2%]. 27 [31.7%] out of 82 patients had both antibodies. No difference was found between the two groups in platelet specific antibodies. Despite significant correlation between flowcytometry and PRA methods, PRA can only detect antibodies which react with complement. With increase in the number of platelet transfusion, immunization to HLA antigens occures; moreover, immunization against platelet specific antigens may also occure during autoimmunity. The presence of these antibodies may be one of the reasons of poor response to platelet transfusion and platelet refractoriness in patients under study. Conducting similar studies with higher number of samples, platelet cross-match, and the use of HLA- matched platelets for these patients are recommended