ANTIBODY-RESPONSE TO KLEBSIELLA-PNEUMONIAE 60 KDA PROTEIN IN FAMILIALAND SPORADIC ANKYLOSING-SPONDYLITIS - ROLE OF HLA-B27 AND CHARACTERIZATION AS A GROEL-LIKE PROTEIN

Objective. To study the antibody response of HLA-B27+ patients with an kylosing spondylitis (AS) and their first degree relatives to the 60 k Da protein of Klebsiella pneumoniae and to characterize this protein. Methods. Sera from 84 individuals were analyzed by ELISA to determine the titer of antibodies against the 60 kDa protein of K. pneumoniae. S ubjects were divided into 3 categories: Group 1: 44 HLA-B27+ AS relate d individuals (35 patients, 9 healthy controls); Group 2: 28 healthy B 27-AS related individuals: and Group 3. 12 healthy B27- non-AS related subjects. The 60 kDa protein of K. pneumoniae was induced at 45 degre es C and purified by electroelution from sodium dodecyl sulfate-polyac rylamide gel electrophoresis. It was characterized as a GroEL-like hea t shock protein (NSP). The recognition of GroEL-like protein was confi rmed by immunoblot of 2 dimension electrophoresis. The response to Gro EL-like protein from other bacteria and the response to lipopolysaccha ride (LPS) was also analyzed by immunoblot. Results. HLA-B27+ individu als (Group 1), independent of their disease status, showed a significa nt higher response to the 60 kDa protein of K. pneumoniae than HLA-B27 - subjects from Groups 2 and 3 (p < 0.0001). This protein was characte rized as a HSP of the GroEL family and designated HSP60Kp. The GroEL o f other enterobacteria as well as that of Mycobacterium leprae were re cognized by HLA-B27+ individuals by immunoblot, whereas HLA-B27- indiv iduals did not. LPS was not recognized by HLA-B27 positive or negative subjects. Conclusion. These findings suggest a relationship between H LA-B27 and the response to a GroEL-like protein that could have implic ations in AS.