Human beta-defensins, faecal calprotectin and TNF- alpha values in stools of preterm and term newborns: Is there a role in innate defense?

Innate antimicrobial peptides [defensins (D) are the most abundant in humans] are considered to play an important role in host defence against microbial invasion. In newborns a few investigations revealed the presence of human -D (hD) in tracheal aspirates and breast milk. Increase of faecal calprotectin (FC) in healthy newborns may be interpreted as a defence mechanism against yeast and fungi. Neonatal T-cells failed to produce a significant amount of TNF- that could provide protection against infections. Aims of the study. To evaluate longitudinally hD, FC, TNF- in stools of healthy preterm and term newborns, in relation to way of delivery [caesarean section (CS) vs. vaginal delivery (VD)] and gestational age (GA). Patients and methods. We enrolled 37 preterm newborns (G1) (mean GA 31.25, mean BW 1870 g, 29 CS, 8 VD) and 30 term newborns (G2) (mean GA 39.27, mean BW 3306 g, 20 CS, −10 VD). Stool samples on day 15th (d15) and 30th (d30) were frozen at −20◦ until use. HD and TNF- were analysed by an ELISA (immunodiagnostic; values: pg/mg faeces). FC was analysed with Calprest kit (Eurospital, Italy; values: /mg faeces). For statistical analysis data were analysed with SAS statistical software package. For split plot design for repeated measures ANOVA was used. Regression model was employed to evaluate relation with GA. Results. Mean FC values increased both in G1 and G2 from d15 (G1: 185.84±101; G2 227.29±87; p < 0.001) to d30 (G1: 201±90; G2 287.11±; p < 0.001) in a statistically significant way (p < 0.001).The increase was higher in VD with respect to CS (p < 0.01) and positively correlated to GA (p = 0.01). Mean TNF- values did not increase from d15 (G1: 47.04±23; G2 35.82±14) to d30 (G1: 53.60±29; G2: 34.59±12) andwas negatively correlated toGA(p < 0.001). Mean hDvalues increased both in G1 and G2 from d15 (G1: 0.79±0.3; G2: 1.08±0.6) to d30 (G1: 1.35±1; G2: 1.25±1) in a statistically significant way (p < 0.001). Conclusions. hD, FC, TNF- are present in intestinal lumen in preterm and term newborns. FC and hD increase in the first month of life; FC is higher in term newborns and in VD, perhaps influenced by intestinal colonization. TNF- is higher in preterms, and could represent a protective mechanism against intestinal infections.