09 Ago Role of vitamin d in seasonal anti-HIV drug exposure and clinical features prediction.

Vitamin D (VD) modulates the expression of genes, including those encoding drug metabolizers and transporters.
Considering immunosuppressive drug levels vary during the year according to VD amount, VD-related markers could explain part of the variability in antiretrovirals (ARVs) exposure and therapy response/toxicity.
Aims of this work are to understand if seasonal variations of exposure are present for anti-HIV drugs and to detect VD-related biological markers predicting the inter-individual variability in ARVs and clinical features in HIV-infected patients.
VD forms and ARVs plasma concentrations are quantified through liquid chromatography, SNPs through real-time PCR.
Preliminary results report a significant trend during the year for nevirapine, efavirenz (EFV) and etravirine, during seasons for dolutegravir (DTG) and between winter and summer for DTG and etravirine; a difference between patients implemented with VD and not is showed for DTG and border-line for EFV.
Concerning EFV and 25-(OH)D3 levels, a significant inverse correlation is observed: EFV levels are significantly higher in VD deficient patients than in insufficient or normal ones.
These preliminary results report the variability of ARVs according to seasons. Moreover, this study showed a relationship between 25-(OH)D3 levels and EFV concentration.
To date, we are still performing analyses and, in future, we expect to obtain the first complete overview of the clinical relevance of the interplay between VD and HIV.