Abstract
The case is reported of a 42 year old white woman meeting currently used diagnostic criteria for both ankylosing spondylitis and systemic lupus erythematosus (SLE). As found in a previously described similar case of a black man, HLA typing showed antigens associated with both SLE and seronegative spondyloarthropathy. This case thus supports the hypothesis that the two diseases occur together only when this rare combination of HLA antigens is present.