Concentrations of Interleukin-10 in Preterm Milk
Despite the protective effects of human milk against necrotizing enterocolitis (NEC), the incidence of NEC is highest in the extremely low birthweight (ELBW) infant, and only minimally decreased with the feeding of human milk. These observations raise a concern that concentrations of bioactive factors may differ in the milk obtained from mothers delivering ELBW infants compared with more mature infants. One such factor that may be affected is interleukin-10 (IL-10), a cytokine that downregulates inflammation and inhibits the production of proinflammatory cytokines. A deficiency of IL-10 in mice causes growth retardation, anemia, and chronic enterocolitis. IL-10 has been found in human milk samples from mothers of full-term infants. We hypothesized that low and/or varying concentrations of IL-10 in preterm human milk might contribute to the development of NEC in the ELBW infant. We compared the concentrations of IL-10 in milk samples obtained from mothers of infants in three groups: 1) 23–27 weeks gestational age (GA), 2) 32–36 weeks GA, and 3) full-term infants 38–42 weeks GA. Milk samples were collected fresh during the first and second weeks postpartum and every two weeks thereafter. IL-10 was quantified using an ELISA sandwich method.