HLA-DQ1 associated with reflex sympathetic dystrophy.

Reflex sympathetic dystrophy (RSD) is a relatively common disabling disorder of unknown pathophysiology. From a cohort of 52 patients, carefully selected to fulfill the recently formulated diagnostic criteria for RSD, venous blood samples were taken for typing of class I and II major histocompatibility antigens. The frequency of HLA-DQ1 was found to be significantly increased compared with control frequencies. The association provides an indication for an organic basis of RSD.