Autoimmune hypothesis of acquired subglottic stenosis in premature infants.

Acquired subglottic stenosis is a devastating additional burden for nearly 4% of premature infants receiving neonatal intensive care. The duration of endotracheal intubation is considered the most important etiologic factor. Surprisingly, most premature infants do not acquire subglottic stenosis. Infants with similar clinical characteristics and care have varying laryngeal outcomes. We hypothesized an autoimmune mechanism to type-II collagen to explain the varying laryngeal outcomes of these infants. A retrospective study of premature infants of comparable birth weight, gestational age, and duration of endotracheal intubation was conducted. The eight control children, who did not manifest symptoms of airway obstruction, had longer durations of intubation than did the infants who developed subglottic stenosis. Three of five affected infants had serum antibodies to type-II collagen, in contrast to none of the control infants (P = .035). This finding warrants additional study, and might lead to new diagnostic and therapeutic measures for these patients.