Association of high levels of alpha-defensins and S100A proteins with Candida mannan detection in bronchoalveolar lavage fluid of preterm neonates

Background.Candida mannan (Mn) detection in bronchoalveolar lavage fluid (BALF) was shown to be useful for earlier identification and preemptive therapy targeting in preterm infants at high risk of invasive candida infection (ICI). We investigated whether early detection of Candida Mn in BALF is associated with the presence of some neutrophilic products, as markers of pre-natal infection/inflammation.Methods.BALF specimens were collected during the first 48 hours of life from preterm newborns mechanically ventilated. Samples were analyzed by high-performance liquid chromatography (HPLC)-electrospray ionization-mass spectrometer. The α-defensins 1-4 and S100A proteins relative amounts were measured by extracted ion current peak area. Absolute and differential white cells counts in BALF were obtained. Mn antigen concentrations were determined by the Platelia Candida antigen kit.Results.Twenty-five studied neonates were divided into two groups: Mn-positive group and Mn-negative group. α-defensins 1-4 and S100A12 levels were significantly higher in the Mn-positive group respect to the Mn-negative group. Moreover, positive significant correlations between the absolute number of neutrophils and the α-defensins 1-4 and S100A8 levels were observed.Conclusion.The detection of Mn-antigen in BALF of preterm infants is consistent with evidence of an innate immune response in their lungs as demonstrated by higher levels of α-defensins and S100A proteins.