Immunoregulatory cell function in peripheral blood leukocytes of patients with intracranial gliomas

Levels of indomethacin-sensitive, glass-adherent, preculture-sensitive, and lymphocyte-mediated immunoregulatory activity were measured in peripheral blood mononuclear cells from 12 patients with intracranial astrocytomas. The levels of regulatory cell function were determined in assays of T cell immunocompetence as judged by phytohemagglutinin (PHA)-induced in vitro lymphocyte DNA synthesis. Of 6 patients studied before surgical exploration and diagnosis, 6 exhibited significantly depressed levels of PHA responsiveness in association with significantly increased levels of regulatory cell function by glass-adherent, preculture-sensitive and/or indomethacin-sensitive cells. Six patients were studied after diagnosis and treatment. Of those, 2 in remission had normal levels of immune function in association with normal levels of regulatory cell activity, whereas 2 of 4 patients who had recurrent disease had significantly depressed T cell function in association with increased glass-adherent, preculture-sensitive and/or indomethacin-sensitive regulatory cell activity. Although some alterations in lymphocyte-medicated suppressor cell activity were seen in 2 patients, those changes could not be correlated with impaired T cell function as measured in the PHA stimulation assay. The changes in regulatory cell function could not be correlated with levels of immune complexes in patient sera. These data suggest that increased levels of regulatory cell function by glass-adherent, preculture-sensitive and/or indomethacin-sensitive cells alone or in conjunction with lymphocyte and T cell depletion are a primary determinant of impaired immunocompetence in glioma patients.