IgD lambda multiple myeloma: immunoglobulin isotype switch after autologous stem cell transplantation.
IgD multiple myeloma (MM) is a rare disease affecting less than 2% of patients with MM, and it is frequently characterized by an aggressive course. It is usually associated with low monoclonal protein levels, so adequate diagnostic procedures have to be performed in order to identify the involved monoclonal component (MC). We present a case of 38-year-old man with acute kidney disease caused by an IgD lambda MM. Diagnosis was achieved by serum protein electrophoresis and immunofixation with anti IgD and IgE antisera. After autologous stem cell transplantations (ASCT) the patient developed a MC different from the original isotype, followed by an oligoclonal bands (OB) pattern. Recently, the occurrence of MC and OB unrelated to the original clone has been proven to be an important favorable prognostic factor in patients with MM who undergo ASCT. The role of the protein laboratory at diagnosis and during follow up of MM patients is highlighted
