Major histocompatibility complex (MHC) gene frequency in acquired dermal macular hyperpigmentation: a case control study.

ABSTRACT

BACKGROUND: Human leukocyte antigen (HLA) allele frequencies have a known association with the pathogenesis of various autoimmune diseases. METHODS: We recruited 31 Indian patients of acquired dermal macular hyperpigmentation (ADMH) and 60 unrelated, age-and-gender-matched healthy controls. After history and clinical examination, 5 ml of blood in EDTA vials was collected. These samples were subjected to DNA extraction and the expression of HLA A, B, C, DR, DQ-A, and DQ-B was studied. RESULTS: There was a predominance of females with a gender ratio of 23 8 and the most common phototype was Fitzpatrick type IV (83.9%). There was a significant association of HLA A*0301 (OR 5.8, CI 1.7-17.0, P = 0.005), HLA B*0702 (OR 5.3, CI 1.9-14.6, P = 0.003), HLA C*0702 (OR 4.3, CI 1.8-9.6, P = 0.001), HLA DRB1*1001 (OR 7.6, CI 1.7-38.00, P = 0.022), and HLA DRB1*1502 (OR 31.0, CI 4.4-341.8, P < 0.001) with patients compared to controls, whereas HLA DQB*0301 was less associated with patients compared to controls (OR 0.2, CI 0.0-0.6, P = 0.009). CONCLUSION: Patients with ADMH are more likely to have the HLA A*0301, HLA B 07*02, HLA C*0702, HLA DRB1*1001, HLA DRB1*1502 and less likely to have the HLA DQB*0301 allele. Larger cohort studies may thus be conducted studying these specific alleles.