Intravenous immunoglobulin treatment of respiratory syncytial virus infections in infants and young children.

Respiratory syncytial virus (RSV)-infected cotton rats (Sigmadon hispidus) and owl monkeys (Aotus trivirgatus) showed significant reductions in RSV shedding from their respiratory tracts following parenteral therapy with human intravenous immunoglobulin (IVIG) containing high titers of RSV-neutralizing antibody. Because this therapy was well tolerated and appeared safe, a double-blind, placebo-controlled IVIG immunotherapy pilot study was performed on 35 hospitalized, RSV-infected infants and children. The treatment was well tolerated and resulted in significant reductions in nasal RSV shedding and in improvements in transcutaneous oximetry readings. However, the mean duration of hospitalization was not reduced by IVIG treatment. Followup to date has revealed no harmful effects resulting from immunotherapy of RSV infections. These studies appear to refute the hypothesis that passively acquired antibody may exacerbate RSV bronchiolitis or pneumonia in infants. Studies with larger numbers of seriously ill children will be required to determine if immunoglobulin G immunotherapy of RSV infections in infants is of clinical value.