In neonates with vitamin D deficiency, low lymphocyte activation markers are risk factors for infection.

ABSTRACTBackground: Vitamin D has regulatory effects on different cells of the immune system and low levels are associated with several immune-mediated diseases.Aim: To investigate the association between neonatal 25-hydroxy vitamin D (25-OHD) level and the expression of lymphocyte activation markers (HLA-DR, CD69, CD25, CD45RA) on T-lymphocyte subpopulations and its impact in neonatal infection.Methods: 25-OHD level was measured in the cord blood of 56 neonates and their mothers using an enzyme immune-assay method. Based on the 25-OHD level, infants were categorised into four groups: severe deficiency (n = 7), moderate deficiency (n = 21), mild deficiency (n = 15) and normal 25-OHD level (n = 13). Mothers were classified into deficient (n = 18), insufficient (n = 21) and normal levels (n = 17). T-lymphocyte subpopulations and lymphocyte activation markers were investigated using flow cytometry.Results: There was a positive correlation between maternal and cord blood 25-OHD levels (r = 0.503, p = 0.001). ...