Platelet antigens and antibodies in multitransfused patients

Following incompatible blood transfusions, anti-HLA and  anti- HPA antibodies may develop and cause various disorders such as post-transfusion purpura, platelet refractoriness, and thrombocytopenia leading to bleeding. The aim of this study was to investigate platelet antigens and antibodies in multi-transfused patients.

In this descriptive study, platelet antigens and presence of platelet antibodies were tested by PCR-SSP and PIFT flowcytometry in 30 Thalassemia major and 30 oncohematologic patients with one hour post transfusion platelet counts in the range of 150000-450000/µl. χ2  test was employed for comparing the results of the study.

Molecular genotyping of HPA-1in thalassemia major patients and patients with oncohematologic disorder in this study revealed that HPA-1a/1a was the most and HPA-1a/1b and  HPA-3b/3b  were the least frequent genotypes. No homozygous cases of 1b/1b, 2b/2b and  5b/5b  were detected. HPA-4b allele was not detected in any patient.  Flow PIFT results revealed platelet antibodies in 10(30%) patients with hematologic disorders and 1(3.3%) thalassemia major patients.

Conclusions  

According to %100 frequency of HPA-4a and total absence of HPA-4b allele and absence of homozygous b/b genotype for HPA-1/-2/-5 alleles in the patient polulation of this study, the prevalence of platelet alloimmunization due to antibodies against these antigens seems to be low. Although further studies in the field are nessessary.