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

摘要： 目的 分析人血浆抗菌肽LL-37、25羟维生素D₃与儿童反复上呼吸道感染的相关性,以期为儿童反复上呼吸道感染的防治提供依据。方法 2018年2－8月选取在河北大学附属医院就诊的24例反复上呼吸道感染患儿为实验组,对照组为24例同期健康儿童。两组对象均空腹采血,检测血浆LL-37、25羟维生素D₃含量,同时记录反复呼吸道感染患儿既往1年内发生上呼吸道感染的次数。结果 实验组患儿血浆25羟维生素D₃含量(18.37±5.50) ng/ml与血浆抗菌肽LL-37水平(3.45±0.98) ng/ml明显低于健康对照组(29.24±9.04) ng/ml、(8.93±2.23) ng/ml(P＜0.05)。实验组患儿血浆25羟维生素D₃含量、LL-37水平均与上呼吸道感染次数呈负相关(r=-0.645、-0.560,P＜0.05);血浆25羟维生素D₃含量与血浆LL-37水平呈正相关(r=0.908,P＜0.05)。结论 维生素D缺乏与反复上呼吸道感染发生有关,反复上呼吸道感染患儿血浆LL-37水平下降,且25羟维生素D₃缺乏可能是反复上呼吸道感染患儿血浆LL-37水平下降的重要原因。

关键词: 反复呼吸道感染, 抗菌肽, LL-37, 维生素D