Abstract

Kusworini Handono , Dian Hasanah , Handono Kalim , Herin Mawarti

TGF-β1 is required for T lymphocytes differentiation toward Treg and Th17.Differentiationtoward Th17 becomes dominant in high levels of IL-6. Some studies showed that vitamin D decreased IL-6 production and increased TGF-β1production. The aim of this study was to investigate the associations among serum levels of vitamin D, TGF-β1/IL-6 balance and Treg/Th17 balance in SLE.Serum levels of vitamin D, IL-6 and TGF-β1, as well as Treg and Th17 percentage were assessed in 41 SLE patients and 20 healthy controls. Serum levels of vitamin D, TGF-β1 and IL-6 were measured using ELISA. Treg and Th17 percentage were the percentage of CD25+FoxP3+CD4+ and CD3+CD4+IL-17+,respectively, detected by flow cytometry. Vitamin D and TGF-β1 levels were lower in SLE (p<0.001 and p=0.004, respectively). While IL-6 levels, Treg percentage and Th17 percentage were higher in SLE (p=0.006, p=0.007, and p=0.017, respectively). Vitamin D levels were negatively correlated to IL-6 levels (r=-0.325, p=0.019). TGF-β1/IL-6 ratio was negatively correlated to Th17 percentage (r=-0.559, p=0.010). Conclusively, in SLE patients whose vitamin D levels are low, IL-6 levels will increase, resulting in dominance of IL-6 over TGF-β1, which direct the differentiation of T lymphocytes toward Th17. The number of Treg will increase to suppress Th17.