Objectives: To determine the most sensitive and specific method of anti-Chlamydia antibody measurement for the serodiagnosis of Chlamydia trachomatis reactive arthritis.
Methods: Immunoblotting, enzyme-linked immunosorbent assays using six synthetic peptides or recombinant antigens and a microimmunofluorescence test were used to determine the presence of IgG, IgM and IgA in serum samples from 17 patients with C. trachomatis reactive arthritis. Twenty patients with other inflammatory arthropathies without evidence of urogenital C. trachomatis infection were used as controls.
Results: The best association of sensitivity (76%) and specificity (85%) was obtained when IgG and/or IgA reactivity to two species-specific antigens was determined. These antigens were synthetic peptides, derived from species-specific epitopes in the variable domain IV of the major outer membrane protein (MOMP) (Labsystems, Finland) and recombinant polypeptide encoded by open reading frame 3 of the plasmid (pgp3).
Conclusions: IgG and/or IgA anti-MOMP-derived peptides and anti-pgp3 could be useful for the diagnosis of probable C. trachomatis reactive arthritis.