Among the clinical manifestations of brucellosis, arthritis may occur in over one-third of the patients. Different articular syndromes have been well recognized: some are definitely infectious in nature, whereas others appear to be reactive. The possibility that B27 and B7-CREG antigens could predispose to the occurrence of brucellar spondylitis was investigated in 14 mestizo Peruvian patients. No association was found. Since there is a low frequency of B27 and B7-CREG in the control population, the possibility that a "native" antigen could be the predisposing one remains to be elucidated. © 1985 Springer-Verlag.