Measles pneumonia in a newborn.

We report a 21-day-old preterm infant who had severe respiratory distress of 6 days' duration and whose lungs revealed a giant cell pneumonia at necropsy. Measles antigen was demonstrated in mononuclear and multinucleated epithelial cells of the lung by immunoperoxidase staining. We recommend the immunostaining procedure to differentiate measles from other viruses, such as parainfluenza 2 or 3, and respiratory syncytial virus, all of which may produce giant cell pneumonias.