Alloimmunization after blood transfusion in patients with hematologic and oncologic diseases.

BACKGROUND: Because of intensive marrow depression and improved survival, patients with hematologic and oncologic malignancies are dependent on transfusion for a longer period. It has been advocated that these patients should receive blood that is matched for blood group antigens other than ABO and D. A retrospective study was performed on the rate of alloimmunization against red cell antigens in 564 patients with malignant hematologic diseases over a period of 10 years. STUDY DESIGN AND METHODS: Records of transfusion and immunohematologic studies of all patients (n = 1066) with malignant myeloproliferative and lymphoproliferative diseases diagnosed between 1987 and 1996 at one hospital were collected from the hospital computer blood bank files. Transfusions were correlated with antibody formation. Factors affecting this correlation were analyzed.
RESULTS: Seventy-one antibodies were found in 51 patients. The overall immunization rate was 9.0 percent. Fifty percent of antibodies were formed after 13 units had been transfused. Once a patient had formed an antibody, the probability of additional antibodies increased 3.3-fold. Anti-c, anti-E, and anti-K composed the majority of antibodies found. Four patients formed Rh system antibodies after incompatible platelet transfusions. Patients who underwent intensive chemotherapy formed antibodies at a much lower rate than other patients. More than 40 percent of antibodies became undetectable after the first detection. No difficulty was encountered in finding compatible blood for these patients.
CONCLUSIONS: Antibody formation in hematologic malignancies is comparable to that in other diseases requiring multiple blood transfusions. Extensive antigen matching before transfusion of patients with hematologic and oncologic malignancies is not necessary and leads to increased costs.