Histocompatibility antigens in multiple sclerosis patients participating in a multicentre trial of azathioprine. British & Dutch Multiple Sclerosis Azathioprine Trial Group.

The human leucocyte antigen (HLA) types of 283 patients with multiple sclerosis participating in a trial of azathioprine treatment were studied. The prevalence of HLA types was compared with those of over 3,300 controls from tissue typing centres in the UK. The prevalence of HLA A3 (38.5% cp 26.1%), HLA B7 (44.9% cp 27.3%) and HLA DR2 (58.3% cp 30.6%) was increased in the multiple sclerosis patients compared with the controls. Age at onset, disease status (relapsing-remitting or currently progressive) and disease severity did not show an association with any particular HLA type.