Rheumatoid factors, anti-filaggrin antibodies and low in vitro interleukin-2 and interferon-gamma production are useful immunological markers for early diagnosis of community cases of rheumatoid arthritis. A preliminary study

Objective. To determine whether measurements of different autoantibodies (A b) and cytokines are useful to distinguish very early rheumatoid arthritis (RA) from other inflammatory rheumatisms. Methods. From a population-based recruitment, 32 patients with very early polyarthritis (median duration: 4 months) were studied. Evaluations at entry (M0), and at 6 (M6) and 12 month s (M12). Ab tested: rheumatoid factors (RF) by agglutination methods and EL ISA, antiperinuclear factor (APF), antikeratin Ab (AKA), anti-Sa and antinu clear Ab. Cytokine production (TNF alpha, IL2, IFN gamma, IL1 beta, IL10) i n whole blood cell culture (WBCC) was determined at M0. At M12, patients we re classified as having RA (N = 15) or other rheumatic diseases. Results. A t M0, AKA/APF and anti-Sa Ab frequencies were low, 13% and 7%, respectively . While most Ab detected at M0 persisted, others appeared during follow-up, particularly APF, which rose from 13 to 40% at M12. At M6, IgM-RF was dete cted in two RA patients exclusively by ELISA, AKA/APF were found to be high ly specific markers for RA (100% specificity). At some time during follow-u p, two RF-negative RA patients were AKA-positive, In two patients, AKA and APF were present at M0 before they satisfied ACR criteria. IL2 and IFN gamm a production was significantly lower (P < 0.05) for RA patients. Conclusion . AKA/APF and anti-Sa Ab were detected in community cases of very early RA. AKA/APF and RF detected by ELISA might contribute to an earlier diagnosis of RA. Low production of IFN<gamma> and IL2 in WBCC constituted a distinct immunopathological feature in very early RA patients. Joint Bone Spine 2001 ; 68 : 144-53. (C) 2001 Editions scientifiques et medicales Elsevier SAS.