Effect of vitamin D on immune function and clinical efficacy in children with recurrent respiratory infections

Objective To understand the effect of vitamin D on immune function and clinical efficacy in children with recurrent respiratory infections (RRI) . Methods From January 2017 to June 2016, 163 children with RRI in Dajiangdong Hospital in Hangzhou were prospectively enrolled, and were divided into treatment group (85 cases) and control group (78 cases) . There were 65 normal children selected as health group. The control group was given routine RRI treatment, and the treatment group was given Alfacalcidol capsule on the basis of this for 3 months. The number of RRIs in the children, the level of 25-hydroxyvitamin D3[25- (OH) D3] in the serum, the immune cells including CD4+, CD8+ and CD4+/CD8+, and immunoglobulin including IgM, IgA and IgG levels were evaluated after 12-month follow-up. Results Before the treatment, the levels of 25- (OH) D3, IgA, IgM, IgG, CD4+ and CD4+/CD8+ in treatment group and control group were all lower than those in health group (P<0.05) . To the end of follow-up, the times of RRI in treatment group was (2.01±0.48) times, which decreased more significantly comparing with the control group [ (4.23±0.82) times] (t=23.30, P<0.05) . The levels of 25- (OH) D3, IgA, IgM and IgG in treatment group were significantly higher than those in control group (t=35.74, 9.99, 11.45, 26.88, P<0.05) . The levels of CD4+ and CD4+/CD8+ in treatment group were also higher than those in control group (t=12.10, 3.17, P<0.05) . There was no adverse drug reaction. Conclusions Alfacalcitol capsules can significantly reduce the number of RRI in children, and can significantly improve serum levels of 25- (OH) D3, as well as Immune cells and immunoglobulins. Key words: Vitamin D; Respiratory infection; Immune cells; Immunoglobulin