HLA-DRB1 in Henoch-Schönlein purpura: A susceptibility study from North India.

Etiology of Henoch-Schönlein purpura (HSP) a small vessel vasculitis remains elusive. Susceptibility may be conferred by major histocompatibility complex. There are limited reports on the association of human leucocyte antigens (HLA) and HSP. The aim was to investigate the association of HLA-DRB1 (HLA class II antigen) with HSP. Forty three patients, <14years, who fulfilled the diagnostic criteria of HSP, laid by 'European League Against Rheumatism' were enrolled. Fifty four age-matched, healthy controls were included. PCR with 24 sequence specific primers for HLA-DRB1 allotypes was performed. Commercially available HLA-DR tissue typing kit (Inno-train, Kronberg im Taunus, Hesse, Germany) was utilized. The mean age of patients and controls was 8.5±3.2 and 7.6±3.6years, respectively (p=0.18). Gastrointestinal and renal involvement was observed in 25 (58.1%) and 14 (32.6%) patients, respectively. A greater frequency of HLA-DRB1*11 was observed in patients (11.6%) as compared to controls (1.9%), however, the results were not significant following Bonferroni correction. No significantly protective HLA genotype was observed. None of the HLA-DRB1 antigen was noted to increase the susceptibility to gastrointestinal or renal involvement. In conclusion, in the first study from India, none of the HLA-DRB*1 genotypes were observed to increase the susceptibility of North Indian children to HSP.