[Distribution of pulmonary neuroendocrine cells--an immunohistochemical study of the lung in autopsied infants including sudden infant death syndrome].

The distribution of pulmonary neuroendocrine cells (PNEC) was analyzed immunohistochemically in 14 victims of sudden infant death syndrome (SIDS), and 10 cases of infant death unrelated to SIDS, excluding congenital heart disease. Lung tissue sections were immunostained with antibodies against chromogranin A (CGA), calcitonin (CT) and gastrin-releasing peptide (GRP). CT/GRP immunoreactivity decreased in older infants of each group, while CGA immunoreactivity showed almost no decrease. Serial section analysis showed some PNEC produced CGA, CT and GRP. However, CGA-immunoreactive PNEC sometimes lacked of CT/GRP immunoreactivity. The difference of PNEC distribution between SIDS and the control cases could not be verified. To date, there have been no studies reported of PNEC distribution in infants by using CGA expression. CGA is considered to be the most useful marker for detecting PNEC in infant lung. Our findings suggest that substances produced by PNEC changed with postnatal development both in SIDS and the control group. This result may be one clue to clarifying the development and function of small airways in infants, allowing further progress in SIDS research.