Immunobiology of primary intracranial tumours. III. Demonstration of a qualitative lymphocyte abnormality in patients with primary brain tumours.

Peripheral blood lymphocytes obtained from patients with primary intracranial tumours respond poorly when stimulated with phytohaemagglutinin (PHA) as compared to lymphocytes from control subjects. This defect could not be corrected by employing purified thymus-derived lymphocytes (T cells) obtained from the peripheral blood of these patients. Moveover, neither increasing the number of lymphocytes placed in culture nor the duration of culture (3-6 days) corrected the defect. Preincubation of these lymphocytes for 24 hr in media supplemented with human AB sera followed by stimulation with PHA did not result in an increase in blast transformation when compared to cells which were not preincubated. However, when the percentage of sheep red blood cell rosetting lymphocytes was determined in a similar type of experiment a marked decrease in the ability of lymphocytes from patients with brain tumours to form rosettes was noted. Quantitation of the number of L-PHA binding sites on lymphocytes from patients with brain tumors revealed that these lymphocytes had approximately twice as many receptor sites per cell as did control lymphocytes suggesting either membrane alterations or changes in lymphocyte subpopulations.