TAMOXIFEN-INDUCED IMMUNE-MEDIATED PLATELET DESTRUCTION - A CASE-REPORT

Drug-induced immunologic thrombocytopenia, a fairly common disorder, i s characterized by drug-dependent antiplatelet antibodies that destroy circulating platelets in the presence of the provoking drug or its me tabolites. The development of reliable methods for the detection of pl atelet-bound immunoglobulins causing in vivo platelet destruction, suc h as the use of monoclonal antibodies tagged with fluorescein and flow cytofluorimetric analysis, has ushered in a new era to differentiate between immune and non-immune thrombocytopenias. A severe thrombocytop enia developed in an elderly female patient treated with tamoxifen, a non-steroidal anti-estrogen drug, after surgery for breast cancer. A t amoxifen-dependent platelet antibody was detected in the patient's ser um and linked on the platelet membranes. This antibody reacted only in the presence of the offending drug and showed platelet specificity. W ithdrawal of drug restored platelet count to normal levels.