Genetic variation in the interleukin 10 gene promoter and systemic lupus erythematosus

Objective. To investigate interleukin 10 (IL-10) gene promoter polymorphisms in systemic lupus erythematosus (SLE) and its clinical subsets. Methods. DNA from 76 Caucasian patients with SLE and 119 controls as genotyped for 3 defined dimorphic polymorphisms (G or A at position -1082, C or T at position -819, C or A at position -592) in the promoter region of the IL-10 gene, using the polymerase chain reaction to amplify the IL-10 gene promoter and oligonucleotide probes specific for each allelic sequence. The frequency of genotypes was compared between patients with SLE and controls, and between clinical subsets of patients with the disease. Results. There was no significant change in the allele frequency of the three IL-10 gene promoter dimorphic polymorphisms in the SLE group compared with controls. However, when subgrouped according to autoantibody status and clinical features, IL-10 -1082*G, -819*C, and -592*C alleles were increased in patients possessing Ro autoantibodies and those with renal involvement. These alleles are in preferential allelic association, namely GCC, ACC, and ATA haplotypes, and the GCC haplotype was increased in these patient subgroups. Conclusion. Polymorphisms within the IL-10 gene promoter that are associated with high IL-10 levels may be important in the development of certain clinical features in SLE.