[Matrix metalloproteinase-3 in patients with systemic lupus erythematosus and its significance in differentiating disease activity from pulmonary infections].

The purpose of this study is to investigate the matrix metalloproteinase-3 (MMP-3) levels in patients with systemic lupus erythematosus (SLE) and its significance in identifying disease activity and pulmonary infections. A total of 122 SLE patients were enrolled, including 21 with pulmonary infections, 16 with arthritis, 26 with nephritis, 10 with vasculitis, and 23 healthy controls. Serum MMP-3, C-reactive protein (CRP), serum amyloid A (SAA), and haptoglobin (HPT) levels were measured in all subjects. The results showed that the levels of MMP-3 in SLE combined with pulmonary infections [(230.10±44.92) μg/L], arthritis [(140.20±20.76) μg/L], nephritis [(155.40±23.36) μg/L] were higher than those in SLE only [(91.74±10.47) μg/L]. The levels of MMP-3 [(210.30±45.71) μg/L], CRP [(12.11±5.21) mg/L], HPT [(1.57±0.23) g/L] in active SLE combined with pulmonary infections were higher than those inactive SLE without pulmonary infections including MMP-3 [(124.00±15.22) μg/L], CRP [(7.76±2.96) mg/L], HPT [(0.89±0.09) g/L]. The levels of CRP [(10.03±2.70) mg/L], SAA [(89.22±36.77) mg/L] in active SLE with pulmonary infections and CRP[(7.76±2.96) mg/L], SAA [(60.22±19.7) mg/L] in active SLE without pulmonary infections were higher than CRP [(1.90±0.39) mg/L], SAA [(17.60±3.89) mg/L] in stable SLE with pulmonary infections. It suggests that the levels of CRP and SAA are elevated in active SLE with pulmonary infections. Serum MMP-3 in combination with CRP may assist in differentiating from SLE pulmonary infections.