HLA-B27 and ankylosing spondylitis: an anti-idiotypic model

Ankylosing spondylitis (AS) is strongly associated with possession of the HLA (Human Leucocyte Antigen)-B27 histocompatibility alloantigen. It is proposed that immunological tolerance to HLA-B27 allows the emergence of a lymphocyte clone with specificity for connective tissue antigens. Such a pathogenic clone would possess idiotypic determinants cross-reactive with determinants on HLA-B27. This hypothesis was investigated using immunoglobulins from HLA-B27 subjects with active definite AS. Immunoglobulin fractions were assayed for HLA-B27-like idiotopes by inhibition of the cytotoxicity of an anti-HLA-B27 antiserum, and by an ELISA technique. The postulated HLA-B27-like idiotope was not detected using these methods.