The human neonate, and especially the premature neonate, is uniquely susceptible to overwhelming bacterial infection. There are a variety of host defense abnormalities in neonates that aid in explaining this phenomenon, including deficiencies in specific antibodies, decreased levels of complement components, abnormalities in the function and number of neutrophils, and deficient T lymphocyte activity.1 Until very recently, the only "gun" in the immunologist's or neonatologist's armamentarium for correcting these host defense abnormalities was immunoglobulin. This, coupled with the rather striking hypogammaglobulinemia observed in premature infants, led many investigators to examine the prophylactic role of immunoglobulin administration in preventing infections in neonates. Early anecdotal information or reports from small, uncontrolled trials suggested that the administration of intravenous immunoglobulin could prevent infection in premature infants weighing less than 1500 g.1
These early trials, which were conducted outside the United States, consisted of small numbers of patients