Plasma cell antigens in human multiple myeloma.

Tumor-specific antigens capable of eliciting a response from autologous lymphocytes have been described in mouse plasmacytoma systems. This paper presents evidence of similar antigens in human myeloma. Myeloma plasma cells isolated from the bone marrow of 27 patients stimulated autologous and allogeneic peripheral blood lymphocytes (PBL) from myeloma patients in mixed leukocyte culture. Plasma cells isolated fromt the bone marrow of normal patients or patients with benign plasmacytosis failed to stimulate PBL in mixed leukocyte culture. Similar results were found in passive cytotoxicity assays with the use of chinken red blood cells (CRBC) coated with 3M KC1 plasma cell extracts from myeloma patients. PBL from myeloma patients caused 30 to 80 percent chromium-51 release from tanned chromium-labeled plasma cell extract-coated CRBC targets, whereas PBL from normal patients or patients with benign plasmacytosis caused only 10 to 25 percent chromium-51 release. This study indicates the presence of material resembling tumor-specific antigens on human myeloma plasma cells. Immune response to suce antigens is elicited in autologous and allogeneic myeloma patients.