[Histiocytosis X and ankylosing spondylitis. A common pathogenesis?]

Histiocytosis X is considered a group of diseases of unknown origin. Nevertheless, the presence of certain lymphocytes disorders and immunocomplexes has permitted us to think that it is an immunologic disease. The ankylosing spondylitis is also a disease of unknown origin, but like the histiocytosis X, might be of immunologic origin. In both entities, a defect of T-lymphocytes has been demonstrated. We present a patient in whom both diseases are associated, which is not reported before in the medical literature. We think that these disorders may be related by a common immunologic alteration.