[Thrombotic thrombocytopenic purpura and ankylosing spondylarthritis. Apropos of a case].

The authors report a case of thrombotic thrombocytopenic purpura (TTP) which revealed a hitherto unrecognized ankylosing spondylitis. After a 4-year follow-up, the spondylitis is still progressing in its axial and/or peripheral form, and TTP has not relapsed. TTP is usually primary, but numerous forms consecutive to various diseases, and notably autoimmune diseases, have been reported. The TTP-ankylosing spondylitis association is extremely rare: analysis of the literature yielded only one case. The authors discuss the hypothesis of a common triggering factor.