Early Persistent Blood Eosinophilia in Necrotizing Enterocolitis Is a Predictor of Late Complications

Background: Eosinophils infiltrate intestinal tissue during necrotizing enterocolitis (NEC) and adult bowel diseases. We theorized that epithelial damage causes eosinophilic activation and recruitment at NEC onset. Objective: We studied the relationship between persistent blood eosinophilia and medical or surgical complications during NEC. Methods: NEC cases and controls at MU Children's Hospital (2008-2013) underwent review. A Likert scale measured NEC severity. We utilized an SPSS database for statistical analyses. Results: Of 50 NEC cases, infants in group 1 (n = 15) had eosinophilia <2 days after onset and those in group 2 (n = 25) had NEC but no persistent eosinophilia. Group 3 (n = 46) consisted of controls, i.e. infants without NEC matched for birth weight and gestational age and group 4 (n = 4) of preterm infants with infection and ≤5 days of eosinophilia. Hematologic assessment defined persistent eosinophilia as ≥5% eosinophils for ≥5 days after NEC onset. Absolute eosinophil counts were 2 times higher in group 1 than in group 2 (p = 0.002). The mean duration of eosinophilia was 8 days in group 1 versus 1 day in group 2 (p < 0.001). A Likert score of NEC severity was 3-fold higher in group 1 than in group 2 (p < 0.001). Compared to group 2, group 1 infants were 8 times more likely to have hepatic fibrosis or intestinal strictures. Conclusions: Early persistent blood eosinophilia is not currently a predictor of complications after the onset of NEC. This biomarker identifies immature infants at a high risk for adverse outcomes during NEC convalescence.