With respect to a potential pathomechanism linking microbial colonization with autoimmunity and induction of SpA, it has been demonstrated that antibodies against Shigella flexneri, Klebsiella pneumoniae and Yersinia enterocolitica may crossreact with HLA-B27, the dominant genetic risk factor of SpA, and that antibodies against Klebsiella were found to be cytotoxic for cells expressing HLA-B27. Whether similar autoantibodies are induced by other members of the microbiota and if yes, under which conditions remains unresolved.
The image shows: Shigella flexneri (Shigellen), group of bacteria. Transmission electron microscopy, negative contrast. Scale = 1 μm. Source: Hans R. Gelderblom, Gabi Schlier, Rolf Reissbrodt/RKI