FOXP3 and systemic sclerosis: In CD4+ lymphocytes derived from individuals afflicted with Systemic Sclerosis (SSc), the application of a naturally occurring vitamin A derivative (all-trans retinoic acid) upregulates FOXP3 expression and, consequently, elevates the population of Tregs by inducing FOXP3 promoter demethylation (69), which may act as a target for treatment in SjS.