The changes in the levels of serum interleukin-13 (IL-13) and nerve growth factor (NGF) in patients with systemic lupus erythematosus (SLE) and their clinical significance were investigated. Sandwich ELISA was used to determine the levels of serum IL-13 and NGF in 35 SLE patients and 15 normal controls. The results showed that the levels of serum IL-13 (92.69±9.87 pg/ml) and NGF (339.69±25.60 pg/ml) in active SLE patients were significantly higher than those in inactive SLE patients (IL-13, 54.22±9.31 pg/ml; NGF, 300.89±33.51 pg/ml) (P<0. 01). The inactive patients also had significantly increased serum levels of IL-13 and NGF as compared with normal controls (IL-13, 35.20±12.70 pg/ml; NGF, 111.40±32.54 pg/ml;P<0.05 andP<0.01, respectively). Spearman correlation analysis revealed that the serum IL-13 levels were correlated with disease activity index of SLE (SLEDAI), ESR and serum levels of C₃ (r=0. 813, 0.504, −0.605, respectively). The serum NGF levels were also correlated with above markers (r=0.442, 0.338, −0.463, respectively). The serum levels of IL-13 and NGF had a positive correlation (r=0.506,P<0.01). It was suggested that IL-13 and NGF might be involved in the pathogenesis of SLE and closely correlated with disease activity.