A triclonal gammopathy in a relapsing multiple myeloma patient, detected by immunosubtraction method

Abstract

Multiple myeloma (MM) is a plasma cell dyscrasia characterized by the malignant proliferation of a plasma cell clone that produces a monoclonal immunoglobulin. Diagnosis and management of patients with monoclonal gammopathies depend on accurate identification and characterization of monoclonal proteins. We present a 67-year-old male patient with anaemia, weakness and weight loss for six months. His physical examination was normal with no fever, and no bone lesions were present in the imaging studies. Laboratory investigations revealed low haemoglobin and albumin concentrations with high total protein and beta 2-microglobulin concentrations. Capillary zone electrophoresis with immunosubtraction method revealed a triclonal pattern of M-protein (IgG κ + IgG λ + IgA κ) which was not prominent with immunofixation electrophoresis. After bone marrow biopsy, MM with triclonal gammopathy was diagnosed and autologous stem cell transplantation was performed. Six months later, again a triclonal M-protein was detected by immunosubtraction method, and a relapse was confirmed with a second bone marrow biopsy. The occurrence of monoclonal and biclonal gammopathies can often be seen upon diagnosis in plasma cell dyscrasias and lymphoproliferative disorders, but triclonal paraproteins are very rare and their clinical significance is unknown. In this particular patient, triclonality was detected by an alternative method called immunosubtraction by capillary electrophoresis. The patient was resistant to therapy suggesting that more than one monoclonal M protein may be a negative prognostic factor, and with new technologies and methods, the number of patients with different monoclonal patterns may increase.

Keywords: Proteins; clinical studies; electrophoresis.