Néonatologie et Gastro-Entérologie Pédiatrique, APHP, Hôpital Saint Vincent de Paul, Université Paris Descartes, Paris, France. florence.campeotto @ svp.aphp.fr
Neonatology. 2010;98(4):365-9. doi: 10.1159/000315872. Epub 2010 Oct 27.
Newborns display high intestinal permeability and a naive adaptive immune system, but infections are rare, indicating strong innate defense mechanisms.
To measure the kinetics of fecal β-defensin-2 (HBD2), an inducible endogenous antimicrobial peptide produced by intestinal epithelial cells, in full-term and preterm infants.
As a first step of this bicentric study, we enrolled 30 healthy full-term infants and 20 healthy preterm infants, with fecal samples collected at days 3, 7, 12 and 30 in full-term infants and at days 15, 30 and 60 in preterm infants. As a second step, we enrolled 10 preterm infants with intestinal distress, either necrotizing enterocolitis (NEC) Bell's stage III (n = 3) or isolated rectal bleeding (n = 7) and 20 controls, cross-matched for gestational age and age at sampling.
HBD2 decreased significantly from day 3 to day 7 (227 ng/g; 14-440 vs. 117 ng/g; 30-470, p = 0.01) then moderately until day 30 (84 ng/g; 10-500) in healthy full-term infants. Healthy preterm infants showed similar high levels between days 15 and 60 (82 ng/g; 30-154 and 85 ng/g; 26-390, respectively). No significant variation of fecal HBD2 levels was observed between infants with clinical features of intestinal distress (77 ng/g, 2-1,271) and cross-matched controls (56 ng/g, 31-164). However, 2/3 infants with NEC and 1/7 infants with isolated rectal bleeding had HBD2 levels above the maximal level observed in controls.
The kinetics of fecal HBD2 in the neonatal period indicate that this inducible defensin can be detected at high level in the feces of full-term and preterm infants, independently of gestational age or mode of feeding. The potential role of fecal HBD2 in detecting NEC is suggested.
新生儿肠道通透性高，适应性免疫系统不成熟，但感染却很少见，这表明其先天防御机制很强。
测量足月和早产儿粪便中β-防御素-2（HBD2）的动力学，HBD2 是一种由肠上皮细胞产生的诱导型内源性抗菌肽。
作为这项双中心研究的第一步，我们纳入了 30 名健康的足月婴儿和 20 名健康的早产儿，在足月婴儿中分别于第 3、7、12 和 30 天，以及早产儿中于第 15、30 和 60 天收集粪便样本。作为第二步，我们纳入了 10 名患有肠道不适的早产儿，包括坏死性小肠结肠炎（NEC）Bell 分期 III 期（n=3）或孤立性直肠出血（n=7）和 20 名对照组，按胎龄和采样时的年龄匹配。
健康的足月婴儿 HBD2 水平从第 3 天到第 7 天显著下降（227ng/g；14-440 与 117ng/g；30-470，p=0.01），然后直到第 30 天适度下降（84ng/g；10-500）。健康的早产儿在第 15 天到第 60 天之间显示出相似的高水平（82ng/g；30-154 和 85ng/g；26-390）。有肠道不适临床特征的婴儿（77ng/g，2-1271）与匹配对照组（56ng/g，31-164）之间粪便 HBD2 水平无显著差异。然而，2/3 的 NEC 婴儿和 1/7 的孤立性直肠出血婴儿的 HBD2 水平高于对照组的最高水平。
新生儿期粪便 HBD2 的动力学表明，这种诱导型防御素可以在足月和早产儿的粪便中以高水平检测到，而与胎龄或喂养方式无关。提示粪便 HBD2 在检测 NEC 中的潜在作用。
