ABSTRACT
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
Subject(s)
Humans , Histocompatibility Antigens/immunology , Antigens, Human Platelet/immunology , Platelet Transfusion , Antibodies , Flow CytometryABSTRACT
The aim of the present study was to evaluate red blood cell chimerism after bone marrow transplantation by flow cytometry. In order to perform this assay, FITC labeled antibodies against blood groups ABH, Rh, Kell, Duffy, Kidd, MNS were used.14 hematologic patients under BMT were selected for this study. The required sample was 5 ml peripheral blood that is collected in tubes containing EDTA. At first, donor and recipients red cells phenotypes were identified with the use of both agglutination and flow cytometry methods; then, on post-transplantation days of 15, 30 and 60, only blood samples of the recipients were analyzed by flow cytometry for the antigens differing from donors to recipients. Antibody screening test and titration of ABH Isohemagglutinins were performed on recipients' plasma samples and then repeated on post-transplantation day of 60. After BMT, red cell chimerism was detected in all 14 patients [in 9 patients on post-transplantation day of 15 and in 5 patients on day of 30]. Antibodies against minor blood groups and Rh blood group were not detected at all. The occurrence of chimerism was not inhibited by ABO incompatibility of donors and recipients but in patients who were ABH incompatible with their donors, ABH isohemagglutinins titer following transplantation decreased. Although the presence of isohemagglutinins did not prevent chimerism but it seems these antibodies by attaching to their related antigens on chimeric red cells membrane prevented corresponding antigen detection. Now by using flow cytometry, red cell phenotyping is applicable and reticulocyte analysis is much easier to perform so that chimerism can be detected in patients who have recently experienced blood transfusion. Moreover, through further evaluation of red cell chimerism and detection of recipient autologous red cells, disease relapse can be predicted