VDR and multiple sclerosis: In this interesting study, a cooperative loop between VitD and oestrogen has been described as calcitriol promotes oestradiol (E2) that reduces transcription of Cyp24a1, the catabolic enzyme for active vitamin, and increases VDR in T cells, which in turn, promotes Treg development.29,64 Therefore, lowered VitD and sex-specific VitD signalling may contribute to the breakdown in T-cell self-tolerance and increased multiple sclerosis incidence in females.