关键词: 反复呼吸道感染, 抗菌肽, LL-37, 维生素D

Abstract: Objective To investigate the correlation between human plasma antimicrobial peptides LL-37 and 25-(OH)D₃ and recurrent upper respiratory tract infections in children,in order to provide evidence for the prevention and treatment of recurrent upper respiratory tract infections.Methods Totally 24 children with repeated upper respiratory tract infection in the Affiliated Hospital of Hebei University from February to August in 2018 were enrolled in experimental group,and 24 healthy children in the same period were selected as control group.Blood samples were taken from both groups on an empty stomach to detect plasma LL-37 and 25-hydroxyvitamin D₃ levels,and the times for upper respiratory tract infections in children with repeated respiratory infections were recorded. Results The plasma level of 25-(OH)D₃ and antibacterial peptide LL-37 in experimental group were significantly lower than those in healthy controls[25-(OH)D₃ : (18.37±5.50) ng/ml vs.(29.24±9.04) ng/ml,LL-37: (3.45±0.98) ng/ml vs.(8.93±2.23) ng/ml,P<0.05)].The plasma level of 25-(OH)D₃ and LL-37 were negatively related to the times for upper respiratory tract infections(r=-0.645,-0.560,P<0.05),and the level of 25-(OH)D₃ was positively correlated with LL-37(r=0.908,P<0.05). Conclusions Vitamin D deficiency is associated with recurrent upper respiratory tract infections.Plasma LL-37 level decreases in children with repeated upper respiratory tract infections,and 25-(OH)D₃ deficiency may be an important cause of decreasing level of plasma LL-37 in children with repeated upper respiratory tract infections.

Key words: recurrent respiratory tract infection, antimicrobial peptides, LL-37, vitamin D