Background Recent evidences suggest a role of transforming growth factor-beta1 (TGF-beta1) in preventing autoimmune diseases, such as systemic lupus erythematosus (SLE).
Objectives The aim of this study was to investigate the relationship of -509C>T polymorphism of the TGF-beta1 gene and TGF-beta1 serum levels with susceptibility to SLE in Bulgarian population
Methods 157 SLE patients and 134 healthy controls were studied. TGF-beta1 serum levels were measured by enzyme-linked immunosorbent assay and genotyping for the -509C>T polymorphism was performed by restriction fragment length polymorphisms (RFLP) - PCR assay.
Results No significant differences in allele frequencies of -509C>T polymorphism of TGF-beta1 gene between SLE patients and healthy controls were observed. Although the genotype frequencies were comparable between patients and controls, higher frequency of heterozygous genotype CT (OR=1.57, 95%CI =0.96$÷ $2.59) and lower frequency of homozygous genotype TT (OR=0.63, 95%CI =0.33$÷ $21.21) was seen in cases versus controls. The -509C>T polymorphism was also associated with some clinical manifestations of SLE: CT genotype was more frequent in patients with hematological manifestations (OR=2.42, 95%CI=1.1$÷ $5.32) and with antibodies to dsDNA (OR=2.0, 95%CI=0.96$÷ $4.2) compared to cases without these clinical features. Our results showed a significantly lower amount of serum TGF-beta1 in SLE patients compared to controls (p<0.001). An association between high TGF-beta1 serum levels and T allele was established in healthy individuals but not in SLE patients.
Conclusions The -509C>T polymorphism of TGF-beta1 gene may be one of the components of genetic susceptibility to SLE in Bulgarian population. In addition, our results support the role of TGF-beta1 as key immunoregulatory cytokine in the pathogenesis of SLE.
Disclosure of Interest None Declared