Transferência passiva de isoaglutininas em transfusão de plaquetas ABO MINOR incompatíveis

Abstract

The presence of IgG anti-A and anti-B isoagglutinins in platelet concentrates may lead to hemolytic transfusional reactions due to passive transfer of these antibodies, especially when present in high titer. No international consensus exists on the critical titer, but some literature considers titers ≥256 as high titer. The passive transfer of isoagglutinins may occur in blood component transfusions with ABO minor incompatibility, that is, when patients from blood groups A, B or AB receive transfusions from blood group O components. The main goal of this study was to establish the IgG anti-A1 and/or anti-B isoagglutinin titer from which the passive transfer of isoagglutinins may have clinical meaning, after the transfusion of blood group O Single Donor Platelets (O-SDP’s). The performance of two independent but related phases permited the study. Between the 1st of June and the 30th of November, 2010, the IgG anti-A1 and anti-B titers were manually determined on all the O-SDP’s donations (n=83) collected in Serviço de Medicina Transfusional (SMT) in IPO-Porto. Patients samples (n=21) of blood groups A, B or AB who received O-SDP’s transfusions (for logistic purposes) were also analyzed. The Direct Antiglobulin Test (DAT) was performed in pre-transfusional samples and samples collected 24 hours after transfusion. Observing positive DAT results, the class of the existing antibody was determined. When a positive result was achieved from the IgG antibody, an erythrocyte eluate was performed to characterize the isoagglutinin type (anti-A1 and/or anti-B). All the tests were based on the Gel Hemagglutination methodology, with reagents and other material commercialized by Diamed®. Of the 83 SDP donors, the IgG anti-A1 titers ranged from 8 (1.2%) to 2048 (2.4%), with 128 as the most frequent (24.1%). The IgG anti-B titers ranged from 2 (1.2%) to 1024 (4.8%), with 64 as the most frequent (25.3%). Of the 83 donors, 21 (25,3%) presented only anti-A1 high titers, 8 (9,6%) presented only anti-B high titers and 7 (8,4%) presented anti-A1 and anti-B high titers, simultaneously. Of the 83 donors, 36 (43,3%) were considered as “high titre” donors. Of the 21 samples analyzed, 4 revealed positive DAT by IgG after transfusion. Of these 4 samples, only 1 revealed the presence of anti-A1 on the Erythrocyte Eluate. No relation was found between the isoagglutinins titer and the transition from negative to positive DAT after the O-SDP transfusion. No hemolytic transfusional reactions were reported after the transfusion. Of the 21 cases, 76.2% responded with an increase of the platelets number. From this study, it was not possible to determine anti-A1 and anti-B isoagglutinins critical titres from which the passive transfer may have clinical significance. However, it was possible to identify that 43,3% of the donors presented titers ≥256 of IgG anti-A1 and/or anti-B, considered as high titer donors.

Date of Award	Feb 2012
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Elísio Costa (Supervisor) & Maria Luísa Borregana Lopes dos Santos Teixeira Corrondo (Co-Supervisor)