Relation between the site of primary intracranial tumors and mitogenic responses of blood lymphocytes.

The possible relation between the site of primary intracranial tumors and mitogenic responses of blood lymphocytes was analyzed in 115 patients who had not undergone surgery or received any radiation or chemotherapy. Some of the patients had however received corticosteroid treatment. PHA responses were impaired in nonsteroid treated patients with tumors affecting the left cerebral hemisphere. They were normal in patients with tumors affecting the right cerebral hemisphere or central structures of the brain or tumors growing in the posterior fossa of the skull. Lymphocyte responses to PPD were normal in patients with hemispheric or posterior fossa tumors. However, the PPD response was sharply reduced in patients with central tumors. The results could not be explained by different histological tumor types or anticonvulsant medication in the various patient groups. In addition, the capacity of sera to promote mitogen stimulation of lymphocytes did not differ significantly between the patient groups. It is speculated that intracranial tumors may interfere with the function of certain centers in the brain which are involved in the regulation of lymphocyte responses.