Implication of regulatory T cells' telomere shortening in pathogenesis of generalized vitiligo

Generalized vitiligo(GV) is a skin depigmenting condition due to loss of melanocytes. Regulatory T cells(Tregs), responsible for peripheral tolerance, show altered numbers and functions in GV patients, likely influenced by the aging process. Therefore, the present study was focused on measuring the relative telomere length of Tregs in 96 GV patients and 90 controls by qPCR, along with correlation of relative telomere length with in vitro Treg suppressive capacity. Interestingly, we found significantly decreased relative telomere length in Tregs of GV patients as compared to controls(p = 0.0001). Additionally, age based-analysis suggested significant decrease in relative telomere length in elderly GV patients(>40 years) in comparison to young GV patients(0-20 years; p = 0.0027). Furthermore, age of onset analysis suggested for reduced relative telomere length in early onset GV patients (0-20 years) in comparison to late onset GV patients(>40 years; p = 0.0036). The correlation analysis suggested positive correlation for relative telomere length with in vitro Tregs suppressive capacity(r = 0.68 & r = 0.45; p < 0.0001). Additionally, the in vitro Tregs suppressive capacity was significantly reduced in elderly GV patients(p = 0.003) and early onset GV patients(p = 0.0074). Overall, our study for the first time demonstrated that, the Tregs ageing due to telomere shortening may be responsible for altered Treg functions and number.