Human beta-defensin-2 WT hBD - 2

Background: Increased expression of antimicrobial peptides including human beta defensins (HBD) has been reported in the amniotic fluid and vaginal secretions of women who deliver preterm. We have previously shown that these women have increased first trimester serum HBD2. The gene encoding HBD2, DEFB4A, is part of a defensin beta (DEFB) cluster on chromosome 8 that is variable in copy number. Increased serum HBD2 is associated with increased DEFB copy number. We aimed to test the hypothesis that variation in DEFB copy number is associated with preterm birth. Methods: In a retrospective, case-control study, genomic DNA and serum were extracted from blood collected from white European women at 11-13 weeks' gestation attending King's College Hospital between March 1, 2006, and Sept 30, 2010. DEFB copy number was determined by paralogue ratio test. Serum HBD2 concentration was measured by ELISA. Data were analysed with Pearson correlation (Excel, version 2010) and binary logistic regression (SPSS, version 20). Findings: Cases were 102 women who either delivered preterm in the index pregnancy or had a history of preterm delivery. Controls were 152 women who had had at least one previous term delivery and delivered at term in the index pregnancy; they had no history of preterm birth. Modal copy number was 4 (range 2-7). Serum was available from 140 women (30 cases, 54 controls, 56 not included in the genetic association study). Median HBD2 concentration was 761·5 pg/mL (IQR 449·6-1232·0). There was no association between DEFB copy number and preterm birth, nor was there a correlation between copy number and serum HBD2 concentration. Interpretation: Although variation in HBD2 protein expression in the first trimester might be useful to predict risk of preterm birth, we found no association between DEFB copy number and preterm birth. Nor did we find a correlation between DEFB copy number and serum HBD2 expression in the first trimester of pregnancy; this might be due to variation in regulatory sequences-some of which are progesterone and oestrogen sensitive-between individual copies. Funding: Wellcome Trust, Wellbeing of Women.

The DEFB4 gene copy numbers were investigated in 206 AD patients and in 250 controls. The levels of the human defensin β-2 (hBD2) and α-defensins (HNP 1-3) in the sera and in the cerebrospinal fluid (CSF) of the patients and the controls were determined. Higher copy numbers of the DEFB4 gene was observed in AD patients as compared with the controls. The levels of hBD-2 and HNP 1-3 were significantly elevated in the sera and in the CSF of the AD patients These data suggest that both defensin β-2 and α-defensins have potential role in the development of AD.

Both bacterial infections and innate oral immunity response participate in development of adeno-tonsillar hypertrophy (ATH). ATH can lead to obstructive sleep apnea. We investigated the beta-defensin 2 (hBD-2) encoding gene, DEFB4, by analyzing the copy number variations (CNVs) of the defensin gene cluster in patients with ATH and by correlating CNV with DEFB4 gene expression. We enrolled 79 patients with ATH, 21 of whom presented with only adenoid hypertrophy, while 58 exhibited hypertrophy of both adenoid and tonsil. CNVs of the defensin gene cluster, DEFB4 mRNA, and hBD-2 protein expression were assessed. Also, beta-defensin 2 was localized histologically using immunohistochemistry. The distribution of defensin gene cluster CNV was similar among the 79 subjects. DEFB4 expression analysis exhibited considerable inter-individual variability, but with neither specific differences among subjects nor correlation with the CNV number. Immunohistochemistry enabled localization of hBD-2 in the tonsil and adenoid epithelium. No differences in localization between the two ATH presentations were found. Inducible antimicrobial defensin peptides exhibited great inter-individual variability in terms of both CNV and gene expression, but no correlation with presentation of ATH was found.