Environmental control in management of immunodeficient patients: experience with "David".

Environmental control in managing patients with immunodeficiency ranges from the exceedingly complex to the relatively simple. At one end of the spectrum is the total isolation technology applied to David, the "Bubble Boy" who lived his entire life behind sterile plastic barriers. At the other end of the spectrum is the simpler technology applied to patients receiving bone marrow transplants who are maintained in ordinary private hospital rooms and attended by personnel who merely observe handwashing precautions. Most properly performed and controlled studies of the use of special isolation procedures to reduce infections derive from patients receiving bone marrow transplants for conditions of aplastic anemia and leukemia or patients receiving chemotherapy for malignancy. The design of isolation procedures for immunodeficient patients borrows from these studies because of the relatively small number of immunodeficient patients. These studies have shown that laminar airflow rooms produce a significantly lower incidence of infections but may not change the mortality of all patients. Also, protective isolation has clearly reduced the incidence and severity of graft-versus-host disease in transplanted patients with aplastic anemia. Recently there has been a trend away from strict isolation procedures because careful studies have indicated that host rather than acquired pathogens are responsible for at least 85% of infections in these special patients. Also, the human stress of prolonged isolation is becoming increasingly recognized. The complex and expensive isolation techniques that were used in David's case are no longer being utilized in immunodeficient subjects, partly because new transplantation technology has made it possible to cross histocompatibility barriers, obviating the need for permanent isolation.