HLA polymorphisms and risk of red blood cell alloimmunisation in polytransfused patients with sickle cell anaemia.

ABSTRACT

BACKGROUND: Red blood cell (RBC) alloimmunisation is an event that may occur due to factors such as numerous blood transfusions, age, gender and genetic factors such as human leukocyte antigen (HLA). AIMS/OBJECTIVES: The aim of the present study was to investigate the possibility of alloimmunisation to red blood cell group antigens associated with the HLA of individuals and to relate alloimmunisation to risk factors. METHODS: A total of 172 polytransfused patients with sickle cell anaemia (SCA) (44 alloimmunised, 128 non-alloimmunised) participated in this study. Blood group genotyping was performed by the DNA microarray method and HLA genotyping by polymerase chain reaction - specific sequence of oligonucleotides. RESULTS: The number of transfusions received directly influenced the incidence of alloimmunisation, and the most common alloantibodies were against Rh (48·8%) and Kell (17%) systems. The HLA-C*06 and HLA-DQB1*03 variants were significantly higher in alloimmunised patients. The HLA-DRB1*04 and HLA-DRB1*11 were more often found in individuals who developed the alloantibodies anti-Fya and anti-K, respectively. CONCLUSION: This study suggests that polytransfused patients with SCA possessing the HLA-DQB1*03 and HLA-C*06 allele variants are more susceptible to alloimmunisation. In addition, HLA-DRB1*04 and HLA-DRB1*11 alleles were seen to be associated with the production of anti-Fya and anti-K antibodies, respectively.