Patients with progressive systemic sclerosis (PSS; scleroderma) were typed for the HLA-A, -B, and -DR antigens. No significant differences in the frequencies of any HLA-A or -B antigen were found. In the subgroup of patients with PSS and diffuse scleroderma (PSS-DS), the frequency of Bw35 was increased (0.30 vs 0.17 in controls;P<0.005,>P>0.2). Although patients with PSS-DS also had an increased frequency of DR1 antigen (0.27 vs 0.12 in local controls;P<0.005,>P<0.05), no="" association="" between="" bw35="" and="" dr1="" antigens="" could="" be="" detected.="" we="" found="" no="" increase="" in="" the="" frequencies="" of="" the="" dr3="" or="" dr5="" antigens="" in="" patients="" with="" pss.="" however,="" in="" a="" subset="" of="" pss="" patients="" with="" pulmonary="" fibrosis,="" an="" increase="" in="" dr3="" and="" a="" decrease="" in="" dr4="" antigens="">P<0.005) were="" observed.="" serum="" antibodies="" to="" centromere="" occurred="" more="" frequently="" in="" dr1-positive="" than="" dr1-negative="" patients="" (0.46="" vs="">P<0.005). this="" study="" of="" a="" large="" number="" of="" patients="" with="" pss="" failed="" to="" confirm="" previously="" reported="" associations="" of="" pss="" with="" the="" hla-b8/dr3="" haplotype="" or="" hla-dr5="">