Cytokines in human milk and late‐onset breast milk jaundice

Background: Maternal milk plays an important role in the development of late‐onset breast milk jaundice (BMJ), possibly due to the unique characteristics of breast milk. The aim of this study was to investigate whether there is a relation between cytokine concentrations in the milk of nursing mothers and BMJ. Methods: Breast milk samples were collected from breast‐feeding mothers of healthy full‐term neonates, 40 with BMJ and 40 without jaundice. Milk samples were taken between the second and the fourth postpartum week. The concentrations of interleukin (IL)‐1 β, IL‐6, IL‐8, IL‐10, and tumor necrosis factor‐α were measured by flow cytometric bead array. Results: There were significant differences between the study groups in terms of IL‐1 β concentrations (P= 0.013). Not statistically significant but similar trends were also seen for IL‐10 (P= 0.067) and tumor necrosis factor‐α (P= 0.053) concentrations. However, no significant differences were noted in IL‐6 (P= 0.174) and IL‐8 (P= 0.285) concentrations. Conclusions: IL‐1 β concentration seems to be increased in milk of mothers whose infants had BMJ. Although the effect of these cytokines on BMJ is unknown, it may cause prolonged jaundice via hepatic uptake, hepatic excretion, conjugation and intestinal absorption.