Immune thrombocytopenia associated with carcinoma.

Both platelet-associated IgG and IgM were quantitatively determined before and after therapy for immune thrombocytopenia in three patients with a recent diagnosis of carcinoma. In one patient, the platelet-associated IgG normalized and the platelet-associated IgM improved after the thrombocytopenia resolved after treatment with steroids, a splenectomy, and a brief course of chemotherapy. In the second patient, the thrombocytopenia improved during treatment with steroids; after further treatment with steroids and chemotherapy, the platelet-associated IgG and IgM decreased. In a third patient who received no specific therapy, the platelet-associated IgG and IgM increased as the tumor progressed. Quantitation of platelet-associated IgG and IgM appears useful in determining which patients with thrombocytopenia and cancer may respond to therapy for immune thrombocytopenia. Patients who respond may then benefit from specific therapy against the primary malignancy.