Association of HLA-DRB1*04 and HLA-DQB1*03 alleles with immune thrombocytopenic purpura in Iranian patients: a case–control study

BACKGROUND: Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder characterized by decreased platelet counts due to immune-mediated destruction. Recently, the role of the human leukocyte antigen (HLA) has been highlighted in the pathogenesis of autoimmune diseases, such as ITP. However, the specific impact of the two HLA alleles, HLA-DRB1*04 and HLA-DQB1*03, on ITP remains unclear. Therefore, this replication study aims to investigate the association between these alleles and ITP, further validating and clarifying the roles of these alleles in Iranian ITP patients. METHODS: Fifty ITP patients and 50 healthy individuals were selected. Then, the genotyping of HLA-DQB1*03 and HLA-DRB1*04 was checked using the Sequence Specific Primer-PCR (SSP-PCR) technique. RESULTS: The patient group showed significantly lower PLT, Hb, HCT, MCH, MCV, and MCHC compared to the control group (P < 0.05), while MPV and PDW were significantly higher in the patient group (P < 0.05). The frequencies of both HLA-DQB1*03 and HLA-DRB1*04 alleles in the patient and control groups showed no statistically significant difference (68.0% vs. 58.0%, P = 0.241, and 30% vs. 18%, P = 0.408, respectively). Neither HLA-DQB1*03 nor HLA-DRB1*04 alleles increased the risk of ITP development (P = 0.301 and 0.163, respectively). In the patient and control groups, there was no significant difference between the frequency of the presence or absence of HLA-DQB1*03 and HLA-DRB1*04 based on gender. CONCLUSION: The HLA-DQB1*03 and HLA-DRB1*04 alleles do not appear to affect the incidence of ITP in the Iranian population. However, larger studies in populations with different genetic backgrounds may provide different results.