Haematological effects of radioimmunotherapy in cancer patients.
The haematologic effects of radioimmunotherapy (RAIT) in cancer patients have been studied in order to better understand the aetiology of RAIT-associated myelosuppression. Evaluations were performed on patients treated with 131I-anti-carcinoembryonic antigen (CEA) and 131I-LL2, a monoclonal antibody (MAb) reactive with non-Hodgkin's B-cell lymphoma. Both groups of patients experienced decreases in WBC and platelets. Nadirs were observed 42-51 d post first injection in the lymphoma patients, and 49-66 d post first injection (30-43 d post high-dose therapeutic injection) in the carcinoma patients. Within the WBC population, B cells were the most radiosensitive. The evaluations of the binding of these MAbs to peripheral blood cells and the effect of RAIT on lymphocyte subpopulations indicated a drop of 26-92% in the percentage of B lymphocytes within 1 week following treatment with both 131I-LL2 and 131I-anti-CEA MAbs even though only LL2 binds to B cells. The percentage of T lymphocytes was not affected by the 131I-antibody treatments. These observations suggest that the marked drop in circulating B lymphocytes and platelets after the administration of radioiodinated antibodies is a nonspecific radiation effect, and not necessarily related to the binding of MAb to normal B cells. Thus, among WBCs, B cells are uniquely radiosensitive, and will be unusually affected by antibody-directed internal radiation.
Stein
R
R
Garden State Cancer Center, Newark, New Jersey.
Sharkey
R M
RM
Goldenberg
D M
DM
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000528:radiation effects; D001792:Blood Platelets / Q000528:radiation effects; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D007962:Leukocytes / Q000528:radiation effects; D008223:Lymphoma / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood* / Q000532:radiotherapy*; D016499:Radioimmunotherapy; D013601:T-Lymphocytes / Q000528:radiation effects; D013997:Time Factors
D000911:Antibodies, Monoclonal; D007457:Iodine Radioisotopes