Department of Pediatrics, Division of Pediatric Pulmonology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Department of Pediatrics, Division of Pediatric Immunology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Pediatr Pulmonol. 2020 May;55(5):1190-1198. doi: 10.1002/ppul.24711. Epub 2020 Mar 2.
Mannose-binding lectin (MBL) is a complement protein involved in the innate immune system, and is associated with some chronic respiratory diseases including noncystic fibrosis (non-CF) bronchiectasis in adults. The aim of this study was to investigate the frequency of MBL2 gene polymorphisms in children with non-CF bronchiectasis, and the effect of MBL deficiency on disease severity.
Fifty children with non-CF bronchiectasis (bronchiectasis group) and 50 healthy controls (control group) were included. The demographic findings, number of acute pulmonary exacerbations in the previous year, airway cultures, pulmonary function tests, and radiologic scores of the bronchiectasis group were recorded. DNA extraction was performed in both groups and MBL2 gene polymorphisms in codons 52, 54, 57 in exon 1 and H/L, Y/X in the promoter region were studied using real-time polymerase chain reaction. Haplotypes were made by genotypes, and MBL serum expression was classified according to the genotypes in the literature.
The bronchiectasis group consisted of 23 (46%) patients with primary ciliary dyskinesia, 5 (10%) with primary immunodeficiency diseases, and 22 (44%) with idiopathic bronchiectasis. There were no statistically significant differences between the bronchiectasis and control groups in terms of allele and genotype frequencies of polymorphisms in codons 52, 54, 57 in exon 1 and promoter H/L. However, the YX heterozygote genotype was more frequent in the control group (82%) compared with the bronchiectasis group (50%) (P = .002). The frequency of patients with intermediate serum MBL expression genotype was higher in the bronchiectasis group (20%) than in the control group (0%) (P = .001). In the bronchiectasis group, there were no significant differences in growth, annual pulmonary exacerbation rates in the last year, pulmonary function tests, radiologic scores, and microbiologic findings between low, intermediate, and high-expressing genotypes.
In children with non-CF bronchiectasis, MBL genotype was different from healthy controls. MBL deficiency associated only with MBL genotype was not related to disease severity in this group of patients.
甘露糖结合凝集素（MBL）是一种参与固有免疫系统的补体蛋白，与一些慢性呼吸道疾病有关，包括成人非囊性纤维化（非 CF）支气管扩张症。本研究旨在探讨非 CF 支气管扩张症患儿 MBL2 基因多态性的频率，以及 MBL 缺乏对疾病严重程度的影响。
纳入 50 例非 CF 支气管扩张症患儿（支气管扩张症组）和 50 例健康对照者（对照组）。记录支气管扩张症组的人口统计学资料、前一年急性肺部加重次数、气道培养、肺功能检查和支气管扩张症放射评分。两组均行 DNA 提取，采用实时聚合酶链反应研究 MBL2 基因外显子 1 中密码子 52、54、57 和启动子区 H/L、Y/X 的多态性。根据文献中的基因型制作单体型，并根据基因型对 MBL 血清表达进行分类。
支气管扩张症组中 23 例（46%）为原发性纤毛运动障碍，5 例（10%）为原发性免疫缺陷病，22 例（44%）为特发性支气管扩张症。在 MBL2 基因外显子 1 中密码子 52、54、57 和启动子 H/L 的多态性的等位基因和基因型频率方面，支气管扩张症组与对照组之间无统计学差异。然而，与支气管扩张症组（50%）相比，对照组（82%）的 YX 杂合基因型更为常见（P=.002）。支气管扩张症组中血清 MBL 表达中间基因型的患者频率高于对照组（0%）（20%）（P=.001）。在支气管扩张症组中，低、中、高表达基因型之间的生长情况、去年的年肺部加重率、肺功能检查、放射评分和微生物学发现均无显著差异。
在非 CF 支气管扩张症患儿中，MBL 基因型与健康对照组不同。MBL 缺乏与 MBL 基因型相关，但与该组患者的疾病严重程度无关。
