Objective: To determine the role of lymphocyte proliferation assay of synovial fluid mononuclear cells (SFMC) with whole fraction bacteria in the diagnosis of reactive arthritis (ReA) or arthritis of unknown origin.
Methods: We stimulated SFMC of 52 unselected patients who consecutively presented in our rheumatology outpatient clinic with the following diagnoses: ReA (n = 8), rheumatoid arthritis (RA) (n = 16), ankylosing spondylitis (AS) (n = 6), osteoarthritis (OA) (n = 5), psoriatic arthritis (PsA) (n = 5) and arthritis of varying origin (AVO) (n = 12) and peripheral blood MC (PBMC) of 10 healthy controls with arthritogenic (Y. entero-colitica, S. enteritidis, C. trachomatis) and non-arthritogenic (E. coli, K. pneumoniae, S. pyogenes, C. albicans) bacteria/mitogens and Tetanus toxoid. T cell proliferation was measured in a standard [3H] Thymidine uptake assay.
Results: In all groups of patients tested, SFMC could be stimulated both by arthritogenic and non-arthritogenic bacteria. So-called specific responses were observed in patients with ReA, but also in RA and AS.
Conclusion: Our findings show that a lymphocyte proliferation assay with SFMC with whole fraction bacteria is not an adequate diagnostic tool to confirm bacterial involvement in inflammatory arthritis.