An immunohistochemical study of islet cells with macronuclei in infancy

The presence of hypertrophic islet cells in infancy as evidenced by nuclear enlargement (2 to 6 times normal size) has been mentioned as a morphological accompaniment of hyperinsulinemic hypoglycemia of infancy. We report an immunohistochemical and semiquantitative study of hypertrophic islet cells in 14 infants with neonatal hypoglycemia (10 with documented persistent neonatal hypoglycemia and 4 with probable persistent neonatal hypoglycemia) and 6 infants born to diabetic mothers (IDM), using an indirect immunoperoxidase methods for the demonstration of insulin, somatostatin, and glucagon. Quantitation of immunoreactivity was performed in each case on 20 hypertrophic cells. Polyploid cells were positive for insulin and somatostatin but negative for glucagon; insulin-positive cells outnumbered somatostatin-positive cells in both groups. As nuclear hypertrophy is considered to be a sign of hyperfunction, our findings are in accordance with the concept that IDM involves reactive beta-cell hypertrophy and similar findings in the pancreases of infants with persistent neonatal hypoglycemia (PNH) suggest a primary dysfunction of their beta cells, too.