Available high- quality RCTs did not support a beneficial effect of cholecalciferol on systemic IL-6 and CRP .
Vitamin d deficiency impacts on expression of toll-like receptor-2 and cytokine profile: a pilot study
Background Vitamin D is believed to play an important role outside the endocrine system in the regulation of the immune system , and in cellular proliferation and differentiation . The aim of the study was to investigate the impact of vitamin D levels on innate immunity . Methods Participants for this prospect i ve , longitudinal study were recruited amongst otherwise healthy staff of a large hospital in Victoria , Australia . Those fulfilling the inclusion criteria , including a vitamin D level of < 50 nmol/L , were supplemented . Using flow cytometry , expression of the innate immune receptors TLR2 , TLR4 and CD86 was measured on peripheral blood mononuclear cells ( P BMC s ) collected prior to vitamin D treatment and then at 1 and 3 months . Additonally , P BMC s at each timepoint were stimulated with specific TLR lig and s and result ant supernatants were assayed for the cytokines TNFα , IL-6 , IFN-α and IP-10 . Results In participants whose vitamin D level was > 100 nmol/L post supplementation ( n=11 ) , TLR2 expression on P BMC s increased significantly , with no change noted in TLR4 or CD86 expression . Stimulation of vitamin D deficient sample s with TLR lig and s produced a number of proinflammatory cytokines , which were significantly reduced upon vitamin D normalisation . In patients whose levels returned to a deficient level at 3 months despite ongoing low-level supplementation , an increase in the pro-inflamamtory state returned . This suggests that vitamin D may play an important role in ensuring an appropriate baseline pro-inflammatory state . Conclusions This ex-vivo pilot study adds clinical evidence supporting a possibly important role for vitamin D in innate immunity . If confirmed , this unique clinical study has potentially significant implication s for the treatment of a variety of inflammatory conditions , where achieving optimal vitamin D levels may help reduce inflammation
Available high- quality RCTs did not support a beneficial effect of cholecalciferol on systemic IL-6 and CRP .