ab21407

Serum matrix metalloproteinase 3 levels in comparison to C-reactive protein in periods with and without progression of radiological damage in patients with early rheumatoid arthritis

M.D. Posthumus, P.C. Limburg, J. Westra, M.A. van Leeuwen, M.H. van Rijswijk

Department of Rheumatology, University Hospital Groningen, The Netherlands

ABSTRACT
Objective
To evaluate serum matrix metalloproteinase 3 (MMP-3) levels in comparison to C-reactive protein (CRP) in periods with and without progression of radiological damage in patients with early rheumatoid arthritis (RA).

Methods
Thirty-two patients with RA and radiological progression (³ 5 points according to the Sharp/van der Heijde method) during 6 months followed by a 6-month period without radiological progression (£ 1 point) were selected from a prospective follow-up study of early RA patients. Serum MMP-3 levels, CRP, the erythrocyte sedimentation rate (ESR), disease activity index (DAS), swollen joint count (SJC), tender joint count (TJC), and Ritchie articular index (RAI) were measured monthly and results were transformed into mean values for the 6-month periods.

Results
During the period with radiological progression the mean serum MMP-3 correlated significantly with the mean CRP (r = 0.68, p < 0.001), ESR (r = 0.54, p = 0.001) and swollen joint count (r = 0.48, p = 0.006). In the period without radiological progression the mean serum MMP-3 only correlated with the mean CRP (r = 0.44, p = 0.012).
Individual changes - expressed in percentages (%) - between the two periods showed a decrease in both the mean serum MMP-3 and CRP in 19 and an increase in 3 patients, in parallel with other markers of disease activity in these patients (69% of cases). The individual change (%) in mean serum MMP-3 or CRP did not correlate with the difference in radiological progression between the two periods.

Conclusions
Serum MMP-3 and CRP are closely related and there seems to be no difference between serum MMP-3 and CRP with regard to the monitoring of the progression of radiological damage.

Key words
Serum matrix metalloproteinase 3, stromelysin 1, early rheumatoid arthritis, radiological damage.

Please address correspondence and reprint requests to: Marcel D. Posthumus, MD, Department of Rheumatology, University Hospital Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands.
E-mail: m.d.posthumus@int.azg.nl