Henoch-Schönlein purpura and cutaneous leukocytoclastic angiitis exhibit different HLA-DRB1 associations

Objective. To examine the HLA-DRB1 genotype of patients with cutaneous leukocytoclastic angiitis (CLA), a small-sized blood vessel vasculitis limited to skin, and determine if differences exist with Henoch-Schönlein purpura (HSP), a small-sized blood vessel vasculitis with cutaneous and systemic complications. Methods. A retrospective study was performed on an unselected population of patients from Northwest Spain with primary cutaneous vasculitis classified according to proposed criteria. Patients who fulfilled classification criteria for hypersensitivity vasculitis were included in this study if they had a biopsy proven leukocytoclastic vasculitis limited to skin and, due to this, they also met the Chapel Hill Consensus Conference on the Nomenclature of Systemic Vasculitis definitions for CLA. Patients were included in this study if they had at least 2 years' followup. We studied 96 Caucasian patients (58 HSP, 38 CLA). Patients and ethnically matched controls (n = 145) were HLA-DRB1 genotyped from DNA using molecular based methods. Results. No HLA-DRB1 genotype differences between patients with CLA and controls were seen. HLA-DRB1*01 was increased and HLA-DRB1*07 reduced in HSP patients compared to controls. When HLA-DRB1 genotypes of patients with CLA and HSP were compared a significant increase of HLA-DRB1*15/16 and especially of HLA-DRB1*07 was observed in the patients fulfilling definitions for CLA compared to those with HSP. Conclusion. HSP and CLA exhibit different HLA-DRB1 genotype associations.