The immunocompromised patient and transfusion.

Immunocompromised patients are usually seriously ill and many such patients, especially those undergoing stem cell transplantation, have prolonged periods of pancytopenia and consequently, heavy transfusion requirements. All transfusions are potentially hazardous but transfusions to immunocompromised patients cause additional problems, which may be immunological or infectious. This review describes these special problems and ways to alleviate them. It should be useful to anyone treating immunocompromised patients particularly specialists in haematology, transfusion medicine, infectious diseases, oncology, transplant surgery, anaesthesia, and neonatology. DiVerent parts of the immune system— either non-specific (phagocytes, complement, etc) or specific immunity (cellular or humoral) or combinations thereof may be aVected. Patients with pure B cell immunodeficiency have few transfusion related problems. Both hereditary and acquired defects of the immune system occur (table 1). Inherited defects requiring transfusions are rare while acquired causes are relatively common. Neonates weighing less than 1200 g are physiologically immunocompromised.