Ankylosing spondylitis in three Zulu men negative for the HLA B27 antigen.

Three cases of ankylosing spondylitis in Zulu men are presented. They are of interest in that all 3 patients were negative for HLA B27, a tissue-typing antigen that is present in the vast majority of Caucasians with the disease. We draw attention to the rarity of ankylosing spondylitis and also of the B27 antigen in Blacks and offer some postulates on the relationship between these two phenomena.