Table 2.

Determination of serum matrix metalloproteinase and tissue inhibitor of metalloproteinase concentrations

	Normal range†	RA (n = 45)	Non-RA (n = 21)	Erosions (n = 12)	No erosions (n = 54)
MMP-1 (ng/ml)	0	4.0 ± 5.5	1.9 ± 2.7	7.1 ± 6.7*	2.5 ± 4.0
MMP-2 (total; ng/ml)	156-254	115 ± 50	112 ± 28	103 ± 25	116 ± 47
MMP-2 (active)	N/A	15 ± 15	15 ± 14	10 ± 8	16 ± 13
MMP-9 (total; ng/ml)	13-61	44 ± 32	49 ± 34	40 ± 35	46 ± 32
MMP-9 (active)	N/A	2.3 ± 3.3	3.3 ± 3.6	2.8 ± 3.5	1.6 ± 3.3
TIMP-1 (μ g/ml)	0.3-0.5	1.6 ± 0.7	2.0 ± 0.9	1.5 ± 0.6	1.7 ± 0.8
TIMP-2 (ng/ml)	29-108	105 ± 166	72 ± 134	140 ± 168	85 ± 54
CRP (mg/dl)	<0.4	2.0 ± 3.9	2.2 ± 2.4	3.2 ± 3.2*	1.9 ± 2.8

Values are expressed as mean ± standard deviation of serum matrix metalloproteinase (MMP) levels measured in 66 patients. Comparison groups were divided into rheumatoid arthritis (RA) and non-RA patients, and subsequently into patients with erosive and nonerosive disease. Erosions were defined as definite erosions in more than one joint (see Patients and method). ^†Normal values provided by the manufacturer of the ELISA kit. Normal values were not available for the assays for active MMP-2 and MMP-9. ^*P <0.01. crp, c-reactive protein; timp, tissue inhibitor of metalloproteinase.