Elevation of serum immunoglobulin M (IgM) level in patients with brain tumors.

Sera of 43 brain tumor patients were analyzed along with various other control groups for serum immunoglobulin, cold and sheep cell hemagglutinin and a heterophile type antibody. Serum IgM and heterophile antibody (non-Forssman type) were found elevated in brain tumor and various acute viral meningoencephalitis groups. Serum IgA and IgG levels were essentially unchanged. IgM levels appear to be particularly stimulated by the meningioma class because the removal of tumor from the host was accompanied by its return to normal range. This system of IgM measurement may prove to be a valuable tool in preliminary diagnosis of brain tumors.