Objective: To study the association between Bcl-2 gene polymorphism and systemic lupus erythematosus (SLE) in Chinese and detect the synergism between IL-10 and Bcl-2 genotypes in determining susceptibility to SLE.
Methods: The peripheral white blood cells from 232 nuclear families of SLE and 106 ethnically matched normal controls were collected and the DNA extracted. The allelic distribution of one microsatellite located in Bcl-2 gene was determined by using fluorescent-labeled primer and genotyping method.
Results: (1) The distribution frequency of Bcl-2 alleles and its major genotypes were significantly different between SLE group and normal controls (P = 0.001 and 0.0029 respectively). (2) Transmission disequilibrium existed in Bcl-2 alleles. Bcl-2-195 bp allele was preferentially transmitted to affected offspring (t: non-t = 122:82, P = 0.0051) by TDT approach. Individuals carrying both Bcl-2-195 bp allele and IL-10G138 bp allele were at higher risk of developing SLE than those carrying only Bcl-2-195 bp allele or IL-10G138 bp allele (OR = 3.00, 1.77, 1.07 respectively).
Conclusion: Bcl-2 gene polymorphism is associated with SLE and may be directly involved in the process of SLE or in linkage disequilibrium with some susceptibility loci nearby. Synergistic effect may exist between IL-10 and bcl-2 genotypes in determining susceptibility to SLE.