Background: Systemic lupus erythematosus (SLE) is a prototype of autoimmune diseases that affects practically every organ in the body. There are strong epidemiological evidences that genes contribute to the risk of developing
many common diseases. The previous study had shown that interleukin-10 (IL-10)-1082G, IL-10-819C, and IL-10-592C haplotype were associated with renal involvement in white patients with SLE. In Chinese patients, a different
IL-10-1087*A /-824*T /-597*A haplotype was also associated with renal involvement. Our study will investigate whether IL-10 promoter polymorphism is a marker of susceptibility of lupus nephropathy.
Methods: The study included 119 Chinese patients with SLE. One hundred unrelated, healthy individuals living in central Taiwan served as control subjects. In SLE patients, not only renal disease (defined as proteinuria >1g/day) but also other clinical and serological data were analyzed. The genomic DNA was prepared from peripheral blood by use of a genomic DNA isolation reagent kit
(Genomaker, Taiwan). Each polymorphism was detected as a result of a polymerase chain reaction (PCR)-based restriction analysis. The polymorphism was divided into digestible (AA homozygote), indigestible (CC homozygote)
and A/C heterozygote. The relationship between the IL-10 gene polymorphism and clinical manifestations of SLE was evaluated.
Results: We did not detect any association of IL-10 genotype with renal disease involvement in the SLE patients. There were also no significant finding in other parameters, including malar rash, photosensitivity, entral nervous system involvement and ANA (all p>0.05). Furthermore, for the genotype and allelic frequency, there were statistically significant differences between the
SLE patients and the normal control subjects (p=0.007, and 0.003, respectively).
Conclusion: We were unable to find significant differences in IL-10 gene polymorphism between SLE patients with renal disease and the healthy control subjects. However, there were significant relation of -627 IL-10 genotype and
allelic frequencies with SLE. It implies that the IL-10 gene polymorphism can serve as a candidate gene marker for further study in patients with SLE.
