Behçet's disease and antibody titers to various heat-shock protein 60s

It has been suggested that the 65 kDa heat-shock protein (HSP) of Streptococcus in recurrent aphthae within the oral cavity may be involved in the uveoretinitis of Behçet's disease, possibly through sensitization of the immune system. To investigate this possibility, we examined serum antibody titers for various members of the 60 kDa family of HSPs and their implications with regard to a role for HSP60s in Behçet's disease. We isolated HSP60 of Streptococcus pyogenes from the margin of oral aphthae in one Behçet's disease patient with severe uveoretinitis and the HSP60s of Yersinia enterocolitica, retinoblastoma cell line clone Y79, and bovine retinal extract and investigated the reaction of each of these HSP60s with 100-fold diluted serum samples from 20 Behçet's disease patients using anti-HSP60 antibody titers determined by ELISA. The anti- Streptococcus HSP60 antibody and anti-retinal HSP60 antibody titers of the 100-fold diluted serum samples from the Behçet's disease patients were both significantly higher than those of similarly diluted serum samples from healthy donors. The results of the ELISA antibody titer assay showed that, although the various HSP60s share a common basic antigenicity, they differed in reactivity to the anti-HSP60 antibodies in the sera of the Behçet's disease patients. The results indicate that subtle but significant differences exist in the antigenicity of the various HSP60s tested, all of which share a common basic antigenicity and are of approximately the same molecular weight, and suggest that an immuno-cross-reaction between retinal and streptococcal HSPs and a related autoimmune response may be involved in the development of Behçet's disease.