Immune-globulin prophylaxis of respiratory syncytial virus infection in patients undergoing stem-cell transplantation

Thirty-two patients undergoing allogeneic hematopoietic stem-cell transplantation were given respiratory syncytial virus (RSV) immune globulin (RSVIG) at the time of transplantation and again 3 weeks later. Antibody titers to RSV, human parainfluenza virus 3, measles, and influenza H1N1, H3N2, and B were measured prior to administration of RSVIG and 6 more times over the course of the subsequent 6 weeks. Baseline antiviral titers and increases in antibody after administration of RSVIG were extremely variable for all the viruses. In 18 patients in whom the baseline titers of antibody titers to RSV-F protein were 1:640-1:2048, there was a 7.7-fold initial increase in these titers after the first dose of RSVIG, compared with a 2.1-fold increase in 14 patients with baseline titers of 1:4096-1:20,840; increases in titers of antibody against the other viruses after the first dose of RSVIG reflected similar variability. The subset of patients with the lowest titers appear to receive the greatest benefit from administration of RSVIG.