Which antibody is abnormal in Waldenstrom macroglobulinemia?

In Waldenstrom macroglobulinemia, the primary abnormality involves the overproduction of immunoglobulin M (IgM). This condition is a type of non-Hodgkin lymphoma characterized by the proliferation of lymphoplasmacytic cells, which leads to elevated levels of IgM in the bloodstream. The excessive IgM can contribute to various clinical symptoms, including hyperviscosity syndrome, which can manifest as weakness, headaches, and visual disturbances due to the thickened blood.

The other immunoglobulins, such as IgG, IgA, and IgE, are not typically associated with this condition. In Waldenstrom macroglobulinemia, while there may be some alterations in these other immunoglobulins, it is the elevated levels of IgM that are primarily recognized as abnormal and central to the diagnosis and management of the disease. Thus, the identification of IgM as the abnormal antibody in this setting is crucial for both diagnosis and therapeutic decision-making in affected individuals.