Cartilage oligomeric matrix protein (COMP)-C3b and COMP in patients and controls. Serum COMP-C3b (A) and COMP (B) were measured in patients with diffuse cutaneous systemic sclerosis (dcSSc) (n = 40), limited cutaneous systemic sclerosis (lcSSc) (n = 40) and healthy controls (n = 97). The longitudinal changes in COMP-C3b (C) and COMP (D) was measured. Statistical significance of differences was measured using the Kruskal-Wallis test with Dunn’s post hoc test (A and B) or the Wilcoxon matched-pairs signed rank test (C and D). ns, not significant; **P <0.01; ***, P <0.001.