Prospective study of the magnitude and duration of changes in tuberculin reactivity during uncomplicated and complicated measles

The suppression of cellular immune responses during measles is thought to contribute to the development of secondary infections which often complicate this disease. To determine whether there was a difference in the altered cellular immune responses of children with and without complications we performed a prospective study of purified protein derivative skin test reactivity in children with natural measles virus infections who had received Bacillus Cal-mette-Guerin as infants. Twenty-five tuberculin-positive children who developed measles (13 uncomplicated and 12 complicated) were skin-tested weekly beginning 1 to 2 weeks before and ending 2 to 7 weeks after the onset of the rash. All children became anergic during the acute phase of measles. Children with complications remained unreactive for a significantly longer period of time after the rash (mean, 4 weeks) than did children without complications (mean, 2.3 weeks, P < 0.001).