Beta-defensin gene (DEFB1) polymorphisms are associated with the susceptibility to chronic respiratory diseases

In the present study, we aim to investigate the correlations between polymorphisms in the DEFB1 gene and the susceptibility to chronic respiratory diseases (CRDs). Electronic searches in multiple scientific literature databases (PubMed, EBSCO, Ovid, Springerlink, Wiley, Web of Science, Wanfang database, China National Knowledge Infrastructure database and VIP database) were made to retrieve studies on the associations between DEFB1 gene polymorphisms and CRDs. We used strict inclusion criteria in the present meta-analysis. Data analyses were performed with STATA software (version 12.0; Stata Corp, College Station, TX, USA). Of 76 initially-retrieved articles, 11 were finally incorporated into our meta-analysis, enrolling 1343 patients with CRDs (477 with chronic obstructive pulmonary disease (COPD), 305 with asthma, 286 with cystic fibrosis (CF), 130 with ventilator-associated pneumonia (VAP), 145 with pulmonary tuberculosis, and 1261 healthy controls into our meta-analysis. Our study showed that -44 C/G (rs1800972) and 1654 G/A (rs2738047) in DEFB1 are strongly associated with the increased susceptibility to CRDs. The subgroup analysis on disease types showed that the -44 C/G (rs1800972) in DEFB1 is associated with the susceptibility to COPD, VAP and CF, and the 1654 G/A (rs2738047) associated with the susceptibility to COPD and asthma. Subgroup analyses based on ethnicity indicated that -44 C/G (rs1800972) may confer increased susceptibility to CRDs in Asians but not in Caucasians. Taken together, -44 C/G (rs1800972) and 1654 G/A (rs2738047) are strongly associated with CRD susceptibility, while associations of SNPs -52 G/A (rs1799946) and -20 G/A (rs11362) with CRDs needs further investigation.