Abstract: Objective: To determine the correlation between the level of serum complement 3 (C3) and metabolic disorder in the patients with psoriasis. Methods: Sixty-three patients with psoriasis vulgaris without systematic treatment (30 cases with normal or lower body weight and 33 cases with overweight body weight or obesity) and 30 healthy controls were enrolled into this study. The difference in the levels of serum C3 between the patients with normal or lower body weight and healthy controls was analyzed by T test. The relationship between C3 level and Body Mass Index, PASI score, blood lipid, blood glucose, blood pressure and metabolic syndrome in the patients was analyzed by Pearson's test or Spermen's test. Results: The levels of serum C3 in the patients with overweight body weight or obesity, normal or lower body weight and healthy controls were 1.37±0.21 g/L, 1.12±0.14 g/L and 1.07±0.10 g/L. The levels of C3 in the patients with psoriasis was positively correlated with body mass index, PASI score, triglyceride, and metabolic syndrome (P<0.05), and negatively correlated with HDL (P<0.05). Conclusion: C3 level may be associated with the occurrence of psoriasis and metabolic disorders in the patients with psoriasis.

Key words: psoriasis, complement 3, metabolic syndrome, body mass index