HS Xu, JR Tiang, L Sun, SM Cheng

Aim Serum IL-6 level and its mRNA in peripheral blood mononuclear cells (PBMCs) in children with idiopathic nephrotic syndrome (INS) were measured.

Patients and methods 11 patients (8 boys and 3 girls, range of ages, 2.6~12, mean of ages, 6.5) were studied. All patients, without fever, infection and abnormal function of liver, were the first episode and had not been treated with steroid and other immune suppressors. Serum IL-6 level were measured by ELISA. Cells in situ hybridization was used to detect the IL-6 mRNA in PBMCs. The control group consisted of 15 healthy children (10 boys and 5 girls, 2.7~13, 6.6).

Results (1) Serum IL-6 levels were significantly higher in the 11 patients, when compared with the 15 normal controls (20.14±13.12 vs 5.38±2.49 pg/ml p<0.01). Positive relationship was found between serum IL-6 level and the 24 hour urine protein excretion (r=0.705, P<0.05). (2) IL-6 mRNA in PBMCs, analysed in computer photo-analysed system, were higher in INS than those in the control (P<0.05). There was positive correlation between serum IL-6 level and its gene expression in INS (r=0.9 18, P<0.05).

Conclusion (1) Elevated serum IL-6 level, interrelated with 24 hour urine protein excretion, may be associated with increased permeability of glomerular basement membrane in INS. (2) IL-6 gene expression in PBMC of INS is abnormal, which indicates that IL-6 may be participated in the immune pathogenesis of INS. Elevated serum IL-6 level may result predominately from abnormal gene expression of IL-6.