Immune response after surfactant treatment of newborn infants with respiratory distress syndrome.

We examined the sera of 68 newborn infants with respiratory distress syndrome; 49 were treated with a natural porcine-derived surfactant preparation and 19 were controls. Serum of the patients was collected before, 3 weeks and 3 months after surfactant treatment. To detect any antibody that had been raised, we applied diluted serum of the babies in an indirect immunoperoxidase staining technique on frozen pig lung tissue specimens. With light microscopy an immune response could be appreciated as a brown reddish deposit in the porcine lung tissue specimens in 4 out of the 49 surfactant-treated and not in the control babies.