Cholecalciferol supplementation, vitamin D status and T‐cell immune phenotype in HIV‐infected children: a randomised controlled trial

Abstract

Purpose of the study: Besides its known effects on bone metabolism, vitamin D may regulate immune function. We performed a randomized controlled trial (RCT) to test whether cholecalciferol supplementation can improve vitamin D status and modulate immune responses in HIV-infected children and youth. Methods: Caucasian vertically HIV-infected patients (aged 8 to 26 years) with vitamin D deficiency and normal parathormone (PTH) levels were randomized into an experimental (n=25) and control (n=25) group to receive 100,000 IU of oral cholecalciferol every 3 months for a total of 4 doses, or placebo. A pre-randomization period (-3 months) was also taken into account to better model within-individual variability. Mixed linear regression models were used to evaluate the between-group changes in the outcomes of interest. The analysis was intention to treat. Summary of results: 47 subjects completed the RCT. Cholecalciferol supplementation produced an early decrease in PTH levels (3 months) and a later concomitant increase in 25(OH)D and 1,25(OH)2D levels (6 months), both persisting up to 12 months. The supplementation had no effect on CD4+T-cell numbers or percentage while was associated with a decreased loge Th1, an increased loge Th2 (nullp<0.05), an increased loge Treg (null nullp<0.01), and and a decreased loge Th17:Treg(nullp<0.05). Conclusions: In our cohort, supplementation with oral cholecalciferol was effective in increasing serum 25(OH)D and 1-25(OH)2D while decreasing serum PTH levels, had no effect on CD4+T-cell count, but was associated with T-cell phenotype changes mainly favoring Tregulatory subset.