Antibodies to Enterobacteriaceae in ankylosing spondylitis

Serological studies on ankylosing spondylitis (AS; N = 82) show that although statistically more AS patients than controls (N = 24) may possess elevated serum titres to enterobacteria such as Salmonella, Shigella and Yersinia, this does not necessarily imply enterobacterial involvement in AS, as other groups without enteritis or arthropathies that frequent health care facilities (N = 72) may also display this phenomenon, presumably due to increased exposure. Moreover, an inventory of all detectable antibody reactivities to the separated cell envelope antigens of five enterobacterial species suspected of involvement in AS (notably Enterobacter, Klebsiella, Salmonella, Shigella and Yersinia) failed to reveal statistical associations with AS. This might be explained, assuming that the aetiology of AS entails a set of enterobacteria rather than a few individual species. It is proposed that serological studies on AS should be supported by additional information, e.g. that of the faecal carriage, and that these combined studies encompassing other enterobacteria, in addition to Klebsiella, might be fruitful.