Histocompatibility antigens in discoid and systemic lupus erythematosus.

A study of histocompatibility (HLA) antigens in 69 patients with discoid lupus erythematosus (DLE) showed an increased incidence of HLA-B7 and HLA-B8 related to the age at onset and sex of the patient. Young females and males aged 15-39 years at onset were associated with HLA-B7 and females aged over 40 years with HLA-B8. This supports previous studies concerning sex and age specific onset rates in DLE which suggests that there is more than one genotype in this disorder. Female patients with systemic lupus erythematosus (SLE) at all ages of onset showed a significant association with HLA-B8. Female patients, with onset 15-39 years, with either SLE or DLE which has transformed to SLE, show a significant increase in HLA-B8 compared with the females in the same age onset group who have the discoid disease. The presence of HLA-B8 in a young female with DLE may represent a risk factor for the development of the systemic disease.