Effect of Maturation at Birth on the Clinical Features of Neonatal Cow's Milk Protein Allergy: A Retrospective Study.

Neonatal immune regulation transitions from fetal immunity and varies with maturation status, but its role in neonatal cow's milk protein allergy (CMPA) remains unknown. We studied the association between maturation status at birth and neonatal CMPA. Clinical and laboratory data of neonates presenting with CMPA symptoms were retrospectively collected from two tertiary hospitals. Patients were assessed according to gestational age at birth: preterm, late-preterm, and full-term. Fifty-five infants (26 females, 14 preterm, 15 late-preterm, and 26 full-term) were included; 44 were negative for milk-specific IgE. Neonatal CMPA was common during moderately premature periods. Preterm infants exhibited longer latency from initial CM exposure to disease onset, lower incidence of bloody stool, and absence of elevated monocyte counts. However, immunoreactivity to CM antigens was retained in all infants. Neonatal CMPA features varied with infant maturation status at birth. Our results improve the understanding of intestinal immunity development, fetal/neonatal immune regulation, and CMPA pathogenesis. What is KnownGraphical Abstract Cow's milk protein allergy (CMPA) affects infants who rely on milk formula as a primary source of nutrition. The clinical features of neonatal CMPA differ from those of older children and vary within the neonatal period.What is New Neonatal CMPA is frequent in the moderately premature period. Clinical features of neonatal CMPA varied depending on the infant's maturation status at birth. Though immunoreactivity to cow's milk (CM) antigen was comparable among all maturation statuses, preterm infants exhibited longer periods from initial CM exposure to disease onset, lower incidence of bloody stool, and absence of elevated monocytes. image