Hl-A antigens associated with rheumatoid arthritis and ankylosing spondylitis in an ethnic homogeneous population.

The HL-A phenotypes of 52 patients with rhematoid arthritis and 26 patients with ankylosing spondylitis from an ethnic homogeneous population have been determined. No definite association has been established with rheumatoid arthritis, while a very significant association has been found between ankylosing spondylitis and HL-A 27 antigen. This finding suggests that certain patients with ankylosing spondylitis have a genetically determined susceptibility to their disease which could be due to a cross-tolerance mechanism enabling infectious agent antigens to mimic certain histo-compatibility antigens, or to a linkage between HL-A genes and those controlling immune responsiveness.