The value of isotype determination of serum antibodies against Chlamydia for the diagnosis of Chlamydia reactive arthritis

Br J Rheumatol. 1996 Jun;35(6):542-7. doi: 10.1093/rheumatology/35.6.542.


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.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antibodies, Bacterial / blood*
  • Arthritis, Reactive / diagnosis*
  • Arthritis, Reactive / immunology
  • Chlamydia / immunology*
  • Chlamydia Infections / diagnosis*
  • Chlamydia Infections / immunology
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Immunoglobulin Isotypes / blood*
  • Middle Aged
  • Predictive Value of Tests
  • Sensitivity and Specificity


  • Antibodies, Bacterial
  • Immunoglobulin Isotypes