Eosinophilia in premature infants: relationship to weight gain.

Serial eosinophil counts were determined in 38 hospitalized, appropriately grown premature infants whose gestational ages ranged from 27 to 35 weeks. Absolute eosinophilia (greater than 700/mm3) was documented in 76% (29/38). Eosinophilia was mild (700 to 999/mm3) in 9, moderate (1,000 to 2,999/mm3) in 17, and marked (greater than or equal to 3,000/mm3) in 3 patients. The average time of onset was day 19. Peak eosinophilia was usually seen within one week of onset and lasted an average of 16 days. A consistent relationship (r = 0.86) was found between the day of peak eosinophilia (mean = day 27) and the day on which birthweight was regained (mean = day 22). No association was apparent between the occurrence or degree of eosinophilia and gestational age, birth stress, presence of umbilical catheter, parenteral alimentation solution, and time of beginning or type or oral feeds. The data suggest that eosinophilia is strongly associated with the establishment of an anabolic state.