Objective:To study the relationship of complement C4 gene polymorphism in children with Henoch-Schonlein nepritis.Methods:Total of 74 ethnic Han children with HSPN and 114 only with HSP,were enrolled,and 130 age-,sex- and ethnic-matched healthy children were used as the control group. complement C4 gene polymorphism were determined by PCR. The correlations between complement C4 gene polymorphism and clinical presentation,pathlogical changes,therapy effect were analyzed. Results:The frequencies of C4AQ0 in HSP(including HSPN)were significantly higher than those in the control group(7.98% vs. 0.77%,P < 0.01,OR=11.19,95%CI:1.45~85.76). The frequencies of C4AQ0 in HSPN did not differ from those in children without nephritis(7.89% vs. 8.11%,P > 0.95). Plasma complement C4 levels in HSPN with C4AQ0(0.22±0.03 g/L)were significantly lower than those without C4AQ0(0.26±0.05 g/L)(P < 0.05). There were no significant difference between C4AQ0 and clinical presentation,pathlogical changes,therapy effect of children with HSPN. Conclusion:Complement C4 gene polymorphism may be associated with the development of HSP and seems unrelated to the susceptibility and clinical presentation,pathlogical changes,therapy effect to HSPN.