Plain language summary
This randomized placebo-controlled double-blind trial investigated whether Vit-D supplementation in a sample of 38 deficient elderly persons, over 65-year olds, could improve influenza seroprotection and immune response. Vitamin D is known to both potentiate the innate immune response and inhibit the adaptive system, and so potentially modulate vaccination response. The participants were randomised into two arms: vitamin D supplementation group (D) and placebo group (P). The D group received 100,000 IU/15 days of cholecalciferol over a 3-month period after which both groups were given the influenza vaccine, and their blood was evaluated 28 days later. Several immune biomarkers were analysed including plasma cytokine profiles, phagocyte ROS production, and lymphocyte cells phenotyping to determine if Vitamin D enhanced immune response to the vaccination. No differences were found in serum ROS and antibody markers. However, Vitamin D supplementation did promote a higher TGFβ plasma level in response to influenza vaccination. Taken together, these results suggest that vitamin D supplementation is not an effective way to improve antibody response to influenza vaccine in deficient elderly people.
Abstract
Background: Immunosenescence contributes to reduced vaccine response in elderly persons, and is worsened by deficiencies in nutrients such as Vitamin (Vit-D). The immune system is a well-known target of Vit-D, which can both potentiate the innate immune response and inhibit the adaptive system, and so modulate vaccination response. Objective: This randomized placebo-controlled double-blind trial investigated whether Vit-D supplementation in deficient elderly persons could improve influenza seroprotection and immune response. Design: Deficient volunteers (Vit-D serum <30 ng/mL) were assigned (V1) to receive either 100,000 IU/15 days of cholecalciferol (D, n = 19), or a placebo (P, n = 19), over a 3 month period. Influenza vaccination was performed at the end of this period (V2), and the vaccine response was evaluated 28 days later (V3). At each visit, serum cathelicidin, immune response to vaccination, plasma cytokines, lymphocyte phenotyping, and phagocyte ROS production were assessed. Results: Levels of serum 25-(OH)D increased after supplementation (D group, V1 vs. V2: 20.7 ± 5.7 vs. 44.3 ± 8.6 ng/mL, p < 0.001). No difference was observed for serum cathelicidin levels, antibody titers, and ROS production in D vs. P groups at V3. Lower plasma levels of TNFα (p = 0.040) and IL-6 (p = 0.046), and higher ones for TFGβ (p = 0.0028) were observed at V3. The Th1/Th2 ratio was lower in the D group at V2 (D: 0.12 ± 0.05 vs. P: 0.18 ± 0.05, p = 0.039). Conclusions: Vit-D supplementation promotes a higher TGFβ plasma level in response to influenza vaccination without improving antibody production. This supplementation seems to direct the lymphocyte polarization toward a tolerogenic immune response. A deeper characterization of metabolic and molecular pathways of these observations will aid in the understanding of Vit-D's effects on cell-mediated immunity in aging. This clinical trial was registered at clinicaltrials.gov as NCT01893385.
Methodological quality
Jadad score
:
5
Allocation concealment
:
Yes
