Plasma gelsolin, the extracellular gelsolin isoform, circulates in the blood of healthy individuals at a concentration of 200 ± 50 mg/l and plays important roles in the extracellular actin-scavenging system during tissue damage. Decreased plasma gelsolin levels have been observed in many inflammatory diseases. In the present study, the variation and potential clinical application of plasma gelsolin levels in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) were analysed. Plasma samples and clinical data were collected from informed and consenting participants: 47 SLE patients, 60 RA patients and 50 age- and gender-matched healthy individuals. Semiquantitative western blotting was used for measuring plasma gelsolin levels. The plasma gelsolin levels in patients with SLE and RA were significantly decreased compared with healthy controls (145.3 ± 40.4 versus 182.7 ± 38.3 mg/l and 100.8 ± 36 versus 182.7 ± 38.3 mg/l, p < 0.001), and plasma gelsolin levels were especially lower in RA than in SLE patients (100.8 ± 36 versus 145.3 ± 40.4 mg/L, p < 0.001). An analysis of the clinical data showed a significant negative correlation between plasma gelsolin levels and SLE Disease Activity Index (SLEDAI) scores (r = 0.659, p < 0.001) but no correlation between plasma gelsolin levels and RA disease activity score 28 (DAS28) (r = 0.076, p = 0.569). Different clinical characteristics were also observed in SLE and RA patients with normal and decreased plasma gelsolin levels.This study found significantly lower plasma gelsolin levels in patients with SLE and RA compared with healthy controls and documented a significant negative correlation between plasma gelsolin levels and SLEDAI, which suggested the potential clinical application of plasma gelsolin in SLE diagnosis and disease activity evaluation. The different clinical characteristics in SLE and RA patients with normal and decreased plasma gelsolin levels indicate differences in the basis of the diseases.
Keywords: Gelsolin; disease activity; rheumatoid arthritis; systemic lupus erythematosus.