Cartilage oligomeric matrix protein (COMP) does not co-localize with C3b in the skin . Skin biopsies from seven patients with diffuse cutaneous systemic sclerosis (dcSSc) and three healthy controls were analyzed for COMP (green) and C3b (red). Nuclear staining is shown in blue. COMP staining was variable in the patients but mainly negative in the controls. Three patients and one control are shown as an example. Upper row, patient with dcSSc for 2 years, no current treatment; second row, patient with dSSc for 13 years, no current treatment; third row: patient with dcSSc for 2 years, one year of treatment with mycophenolate mofetil; fourth row, healthy control. The scale bars indicate 100 μm.