Studies of HLA-B27-associated disease.

Several rheumatic diseases were first shown to be associated with human leukocytic antigen (HLA)-B27 in 1973. Recent developments in understanding this association include the finding that there are at least six variants of HLA-B27 at the molecular level, with no one variant preferentially associated with disease. Detailed studies of the structure of the HLA-B27 molecular family are in progress in several laboratories. Mice expressing HLA-B27 and transmitting it to their offspring (transgenic mice) have been produced and are being studied for their response to bacteria that are known to trigger reactive arthritis in B27+ humans. A particular restriction fragment length polymorphism was recently claimed to be a genetic marker for an additional risk factor in ankylosing spondylitis, but two other laboratories have failed to confirm this finding.