Serum soluble interleukin-2 receptor predicts early remission in patients with recent-onset rheumatoid arthritis treated with a single disease-modifying antirheumatic drug
A. Kuuliala1, M. Leirisalo-Repo2, T. Möttönen3, P. Hannonen4, M. Nissilä5, H. Kautiainen5, M. Korpela6, H. Julkunen7, M. Hakola4 and H. Repo8, for the FIN-RACo Trial Group
1Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki; 2Division of Rheumatology, Helsinki University Central Hospital, Helsinki; 3Division of Rheumatology, Turku University Central Hospital, Turku; 4Department of Medicine, Jyväskylä Central Hospital, Jyväskylä; 5Rheumatism Foundation Hospital, Heinola; 6Division of Rheumatology, Tampere University Hospital, Tampere; 7Department of Medicine, Peijas Hospital, Vantaa; 8Division of Infectious Diseases, Helsinki University Central Hospital, Helsinki, Finland.
ABSTRACT
Objective
To study the value of baseline serum levels of circulating soluble interleukin-2 receptor (sIL-2R) and soluble E-selectin as predictors of early remission in patients with recent-onset rheumatoid arthritis (RA) receiving a single disease-modifying antirheumatic drug (DMARD) (SINGLE) or therapy with a combination of DMARDs (COMBI).
Methods
Baseline (n = 157) serum samples originate from the FIN-RACo (FINnish Rheumatoid Arthritis Combination therapy) trial, in which 195 patients with early and clinically active RA were randomly assigned to receive either SINGLE (initially sulfasalazine) with or without prednisolone, or COMBI therapy (sulfasalazine, methotrexate, hydroxychloroquine, and prednisolone). Of the samples, 76 were from SINGLE patients and 81 from COMBI patients. sIL-2R was measured by automated immunoassay analyzer and sE-selectin by enzyme-linked immunosorbent assay.
Results
At six months, 7 (9% [95% CI: 4 to 18]) SINGLE and 19 (23% [95% CI: 15 to 34]) COMBI patients were in remission. In multivariate logistic regression analysis, sIL-2R < 442 U/ml and COMBI therapy were the only predictors of remission. The area under receiver operating characteristic curve for sIL-2R level was 0.86 (95% CI: 0.62 to 0.95) in SINGLE and 0.57 (95% CI: 0.42 to 0.71) in COMBI (p = 0.006). In SINGLE, the optimal cut off-point was 442 U/ml, lower levels predicting remission with sensitivity of 83% (95% CI: 73% to 91%) and specificity of 86% (95% CI: 42% to 100%). Likelihood ratio for positive test was 5.9 (95% CI: 1.6 to 32.8).
In multivariate logistic regression analysis, sIL-2R < 442 U/ml and COMBI therapy were the only predictors of remission.
Conclusion
Low baseline serum sIL-2R level predicts early remission of patients with active early RA treated with a single DMARD.
Key words
Soluble interleukin-2 receptor, soluble E-selectin, rheumatoid arthritis, combination therapy, remission.
Supported by grants from the Finnish Cultural Foundation, Paulo Foundation, Helsinki University Central Hospital Research Funds, the Finnish Society of Rheumatology, the Rheumatism Research Foundation in Finland, Medical Research Foundation of Turku University Central Hospital, and the Finnish Office for Health Care Technology Assessment.
Please address correspondence to: Antti Kuuliala, Dept. of Bacteriology and Immunology, Haartman Institute,
PO Box 21 (Haartmaninkatu 3), FIN-00014 Helsingin Yliopisto, Finland.
E-mail: antti.kuuliala@helsinki.fi
Clin Exp Rheumatol 2005; 23: 243-246.
© CLINICAL AND EXPERIMENTAL RHEUMATOLOGY 2005.