Objective: To investigate the interleukin-10 (IL-10) gene -592 A/C polymorphism in Chinese patients with lupus nephritis (LN) and evaluate the role of lL-10 in the pathogenesis and clinical/pathological diversity of LN.
Methods: Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses were used to detect the IL-10 gene -592 A/C polymorphism in 265 LN patients and 100 ethnically matched controls. Frequencies of the genotypes were compared between LN patients and controls and among LN patients with different pathological classes. The clinical and pathological characteristics of the patients with different genotypes were also analyzed. Serum IL-10 levels of the patients were determined by ELISA.
Results: No significant differences were found in the distribution of the polymorphism between healthy controls and LN patients. The parameters of disease activity index (DAI), percentage of positive serum anti-dsDNA antibodies, proteinuria and hematuria, and frequency of glomerular thrombi were all higher in patients with -592 AC/CC genotypes than those with AA genotype. AC/CC genotypes were more frequent in patients with LN-IV than in those with LN-II and Va. There was no significant difference in the serum IL-10 levels in patients with these three genotypes.
Conclusion: The IL-10 gene -592 A/C polymorphism appears to be associated with disease activity and renal pathology of LN, but not associated with LN susceptibility or serum IL-10 levels. Patients carrying the -592 C allele had a higher risk of diffuse proliferative glomerulonephritis, indicating the genetic influence of the IL-10 gene polymorphism in the renal lesions of LN.