Abstract
Background: Inflammatory cytokines are important in determining induction of T cell subtypes. Their production and the percentage of regulatory T cells (T reg) has been shown to be influenced by the presence of vitamin D.
The relevance of these findings in relation to tuberculosis is that whilst T reg function regulates the pathological consequences of infection, their presence may also down regulate the immune response resulting in persistence of infection in latent disease.
Methods: As part of an observational study T cell cytokine analysis (IL2, TNFα, IFNγ and IL17) in health and latent TB was carried out ex vivo and following stimulation with Staphylococcal enterotoxin B (SEB) and Purified Protein Derivative (PPD). The effect of vitamin D on stimulated T- cell cytokines in health and latent disease was explored.
Results: There was no significant difference in cytokine production from stimulated CD4+ cells ex vivo (p>0.05) suggesting that T cell response does not differ between those in health and latent TB.
Vitamin D supplementation resulted in a significant reduction in IL2, TNFα (p<0.05), IFNγ (p<0.001) and under certain conditions IL17 production (SEB group). The levels of cytokines were comparable between the healthy and latent populations but PPD stimulation resulted in a blunted response with the effect of vitamin D only reaching significance in TNFα production (p<0.005).
Conclusion: Vitamin D significantly influences T cell cytokine production. The ex vivo response and the effect of vitamin D on stimulated T cells in health is reflected in latent TB. This suggests T cells of latently infected patients are unlikely to be defective in their immune response.
- Copyright ©the authors 2016
