Rapid Clearance of Cytomegalovirus-Specific IgG After Repeated Intravenous Infusions of Human Immunoglobulin into Allogeneic Bone Marrow Transplant Recipients

Abstract
We studied the kinetics of the disappearance of CMV-specific IgG from the serum of 18 allogeneic bone marrow transplant recipients who were receiving repeated intravenous infusions of immunoglobulin. Peak serum titers occurred 24–48 hr after infusion. The mean half-life of IgG to CMV varied from 30 to 70 hr. Additional studies showed that this unexpectedly short half-life was not specific for either the preparation used or the type of patient studied. Repeated treatment did not prevent patients from developing CMV infections (incidence, 50%); however, none of the patients developed CMV interstitial pneumonitis. Treatment had to be discontinued for one patient because of a serum sickness-like syndrome. Our results suggest that rational, time-sequential passive immunization regimens should be developed.