title: The value of isotype determination of serum antibodies against Chlamydia for the diagnosis of Chlamydia reactive arthritis.
abstract: In clinical rheumatology, the diagnosis of Chlamydia reactive arthritis is difficult because an incomplete form of the disease can closely resemble an undifferentiated seronegative mono/oligoarthritis. We investigated whether measuring specific isotypes of anti-Chlamydia antibodies in serum can improve the diagnosis, by comparing such antibody concentrations in the serum of patients with well-defined disease, i.e. Chlamydia trachomatis sexually acquired reactive arthritis (CT-SARA), with other arthritides. Antibody levels were determined by enzyme-linked immunosorbent assay (ELISA). When considering two different isotypes and their combination, the best sensitivity (63%) was obtained for IgM and/or IgA results with a specificity of 81%. The patients with CT-SARA and SARA had the highest levels of antibodies of all isotypes tested. It is concluded that, in our experimental conditions, only very high values of specific isotypes could indicate a diagnosis of Chlamydia reactive arthritis.
authors.affiliation: Division of Rheumatology, University Hospital, Geneva, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Bas
authors.forename: T
authors.initials: T
authors.lastname: Cunningham
authors.forename: T K
authors.initials: TK
authors.lastname: Kvien
authors.forename: A
authors.initials: A
authors.lastname: Glennås
authors.forename: K
authors.initials: K
authors.lastname: Melby
authors.forename: T L
authors.initials: TL
authors.lastname: Vischer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D016918:Arthritis, Reactive / Q000175:diagnosis* / Q000276:immunology; D002689:Chlamydia / Q000276:immunology*; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000097:blood*; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D000907:Antibodies, Bacterial; D007132:Immunoglobulin Isotypes