The transforming growth factor-β1 gene polymorphism (G915C) is not associated with systemic lupus erythematosus

Abstract

Lymphocyte production of transforming growth factor (TGF)-β₁ is decreased in systemic lupus erythematosus (SLE). The lack of this immunoregulatory cytokine may contribute to the characteristic T cell disregulation and aberrant B cell stimulation in SLE patients. The less common C allele of the TGFB1 polymorphism (G915C) is associated with a lower TGF-β₁ production capacity. We performed a population-basedcase - control study to analyse the impact of this polymorphism on disease susceptibility, on clinical SLE manifestations and autoantibody production. A total of 203 German Caucasian SLE patients (fulfilling the 1982 ACR criteria, disease duration 11.5±7.0 years) and 158 ethnically, age- and sex-matched healthy controls were genotyped with a mutagenically separated polymerase chain reaction. There were no significant differences in the genotype distribution and allele frequencies between patients (915 C = 0.08) and healthy controls (915 C = 0.10). Comparing subgroups of patients, we found no association of major disease manifestations or specific autoantibodies with TGFB1 genotypes or alleles. The TGFB1 polymorphism (G915C) neither significantly contributes to the disease susceptibility, nor predisposes to clinical and immunological manifestations typical of SLE. Further studies are needed to corroborate the pathogenic role of TGF-β₁ in SLE patients and to identify the precise genetic elements controlling its production.