Waldenström's macroglobulinemia

　　Waldenstr?m's macroglobulinemia （WM, also known as lymphoplasmacytic lymphoma） is cancer involving a subtype of white blood cells called lymphocytes. The main attributing antibody is IgM. It is a type of lymphoproliferative disease, and shares clinical characteristics with the indolent non-Hodgkin lymphomas.
　　It is named after the Swedish physician Jan G. Waldenstr?m, who first identified the condition.
　　WM was first described by Jan G. Waldenstr?m （1906–1996） in 1944 in two patients with bleeding from the nose and mouth, anemia, decreased levels of fibrinogen in the blood （hypofibrinogenemia）， swollen lymph nodes, neoplastic plasma cells in bone marrow, and increased viscosity of the blood due to increased levels of a class of heavy proteins called macroglobulins.
　　For a period of time, WM was considered to be related to multiple myeloma due to the presence of monoclonal gammopathy and infiltration of the bone marrow and other organs by plasmacytoid lymphocytes. The new World Health Organization （WHO） classification, however, places WM under the category of lymphoplasmacytic lymphomas, itself a subcategory of the indolent （low-grade） non-Hodgkin lymphomas.