Transforming growth factor-β2 polymorphism and systemic lupus erythematosus

Objective. To determine whether transforming growth factor-β2 (TGF-β2) gene polymorphism is associated with systemic lupus erythematosus (SLE) susceptibility. TGF-β is a multifunctional family of cytokines important in tissue repair, inflammation and immunoregulation. SLE is thought to be a T cell dependent autoimmune disorder with T cell dysfunction. Due to its known suppressive effects on interleukin 2 dependent T cell growth, TGF-β2 is considered to be a candidate SLE susceptibility gene. Furthermore, SLE has been linked with a region to which the TGF-β2 gene has been mapped. Methods. Association studies were performed in 3 case-control populations, from Spain, Turkey, and UK, using a TGF-β2 5′-untranslated region (5′-UTR) 4 base pair (bp) insertion polymorphism. Genotyping was performed using fluorescent labeled polymerase chain reaction product sizing. Results. No significant differences were detected in TGF-β2 5′-UTR polymorphism allele frequencies between SLE patients and matched controls in the 3 populations studied. Conclusion. The 4 bp insertion polymorphism within the TGF-β2 gene does not appear to be associated with SLE. However, this does not rule out the possible involvement of TGF-β2 in the disease pathogenesis.