Image: A colored scanning electron micrograph (SEM) of T lymphocytes (green) bound to antigens on a cancer cell (Photo courtesy of The Scientist).
Vitamin D refers to a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, phosphate, and zinc and multiple other biological effects. In humans, the most important compounds in this group are vitamin D3 (also known as cholecalciferol) and vitamin D2 (ergocalciferol).
Previous studies have demonstrated that vitamin D affects T-cell function and maturation via the vitamin D receptor, but no studies in children have been performed on this topic. Most of the T-cell memory is formed in the first five years of life, and the association between serum 25-hydroxyvitamin D (25(OH)D) levels and numbers of circulatory naive, central memory (Tcm), and effector memory (Tem) T lymphocytes in a large population of healthy children hs been investigated.
Scientists at the Erasmus Medical Center (Rotterdam, the Netherlands) and their colleagues measured among 3,189 children participating in a population-based prospective cohort, 25(OH)D levels and performed detailed immunophenotyping of naive and memory T lymphocytes at a median age of 6.0 years (95% range 5.7-7.9). Detailed lymphocyte subsets were available in 986 children. Multivariable linear regression analyses were performed to determine the association between 25(OH)D and the maturation of T lymphocytes in children adjusted for cord blood 25(OH)D levels, herpes seropositivity, sociodemographic and lifestyle confounders.
The team found that higher 25(OH)D levels were associated with higher numbers of Tem lymphocytes. Every 10 nmol/L higher 25(OH)D was associated with 2.20% (95% confidence interval (CI) 0.54-3.89) higher CD4TemRA, 1.5% (95% CI 0.38-2.62)) higher CD4TemRO, and 1.82% (95% CI 0.11-3.56) higher CD8TemRA cell numbers. Generally, stronger associations were observed among boys. 25(OH)D levels were not significantly associated with naive, Tcm cell numbers, herpes seropositivity, or upper respiratory tract infections. The authors concluded that their results suggest that vitamin D enhances cellular immunity in young children. The study was published on August 7, 2017, in the journal Pediatric Allergy and Immunology.
Erasmus Medical Center