IL10 and systemic sclerosis: These findings suggest that the effect of vitamin D in this context is in part directly related to its activity on crucial pathways of fibrosis development and in part to the modulation of the immune system; indeed, in blood samples collected from SSc patients, vitamin D supplementation increased IL-10 production by T-reg lymphocytes providing a “suppressive” cytokine milieu able to modulate immune response [31].