ABO blood group and secretor status in the spondyloarthropathies.

The postulated role of infectious agents, genetic susceptibility of the host to infection and their interaction in the pathogenesis of ankylosing spondylitis, other spondyloarthropathies, and the associated primary (non-arthritic) diseases are reviewed. Compared with a local control population there is a significantly increased prevalence of non-secretors amongst different groups of patients with spondyloarthropathy: ankylosing spondylitis, reactive arthritis and psoriatic arthropathy. No differences between secretor and non-secretor patients with respect to serum and salivary IgA levels, the occurrence of eye lesions or peripheral joint disease have been found. There is no evidence that ankylosing spondylitis or other spondyloarthropathies are associated with any particular ABO blood group. The association between non-secretion and ankylosing spondylitis strengthens the hypothesis that ankylosing spondylitis has an infective aetiology. It also suggests several pathogenetic mechanisms which may be relevant to the initial host-parasite interactions in the spondyloarthropathies.