Multiple myeloma: light chain isotype suppression--a marker of stable disease at presentation

Prognosis in multiple myeloma (MM) is related to the establishment of an immunologically and kinetically characteristic plateau phase. Patients who present with this state may not benefit from immediate chemotherapy. We assessed 20 patients with MM who were staged according to the Salmon and Durie classification at diagnosis and monitored throughout the course of their disease. Patients with a lambda paraprotein and a kappa/lambda lymphocyte ratio in the blood greater than 4.0 were considered to demonstrate light chain isotype suppression (LCIS). Similarly, patients with a kappa paraprotein and a kappa/lambda ratio of less than 0.55 were also considered to have LCIS (1). 14 patients had LCIS; of these, 6 were classified as stage IA, 2 as stage IB, 3 as stage IIA, and 3 as stage IIIA. 6 patients did not have LCIS; 3 were classified as stage IIA, 1 as stage IIIA and 2 as stage IIIB. 10 patients with LCIS were assessed for treatment benefit following administration of melphalan and prednisone, as defined by a fall in the serum paraprotein level of greater than 50% over 6 months. In 8 patients the serum paraprotein levels did not fall, and the patients remained in good health without clinical deterioration. Thus LCIS at presentation may indicate patients in whom treatment can be safely deferred or in whom aggressive therapy is not indicated.