Immunocytochemistry performed on myeloma samples with anti-MAGE monoclonal antibody 57B. (A) MAGE+ myeloma cell line EJM. (B) MAGE+ myeloma cell line U266. (C) MAGE− myeloma cell line Fravel. (D) Gut biopsy from patient no. 29, a patient with MAGE+ stage III myeloma treated by chemotherapy, who developed skin and gut plasmacytomas. The cells stained in brownish red are malignant plasma cells infiltrating the gut mucosa. The epithelium is indicated by an arrow. (E) Bone marrow smear from patient no. 21, a patient with MAGE+ stage III myeloma. All the plasma cells are stained in red. (F) Bone marrow cytospin from patient no. 43, who had a myeloma in relapse after 2 autografts. Some malignant plasma cells are stained in red. The arrows indicate 2 unstained myeloma cells. The slides incubated with the isotype-matched irrelevant monoclonal antibody remained negative, as did cytospins of MAGE-negative bone marrows from stage III myeloma patients incubated with antibody 57B (data not shown).