Determination of serum interleukin-13 and nerve growth factor in patients with systemic lupus erythematosus and clinical significance.

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 and P<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.