Immunological studies of newborn infants with hyperbilirubinemia.

In order to study the immunocompetence of severely jaundiced newborn infants and the possible role of infection in the pathogenesis of neonatal hyperbilirubinemia, 74 newborn infants with varying degree of jaundice were studied with respect to several immunological parameters. The results showed that neonates with total serum bilirubin more than 20 mg/dl had statistically significantly higher numbers of white blood cells (WBCs), band form granulocytes, polymorphonuclear leukocytes (PMNs) and monocytes with Fc and complement (C') receptors and elevated serum IgM than did those with lower serum bilirubin. It is therefore concluded: 1) There is no difference in immunocompetence between severely and mildly jaundiced newborn infants, 2) Infection may play some role(s) in the pathogenesis of neonatal hyperbilirubinemia and 3) Determinations of total WBCs, band form granulocytes, phagocytes with Fc and C' receptors and serum IgM level are of help in the diagnosis of infection in the newborn period.