There was no significant difference in IL-2 values of the control group and preoperative values of the tumour group except for meningioma and acustic neurinoma. We think that macrophages and glycoaminogaycans which encapsulate the tumour prevent stimulation of T helpers by the tumour antigens, so IL-2 is not secreted from the T helpers.

Probably for the same reason we could not find significant TNF values between the control group and the preoperative tumour group. Postoperative decrease in IL-2 is considered to be the result of corticosteroids used for 7 days. Increased TNF values in the postoperative tumour group can be due to the breakdown of the glycoaminoglycan barrier and stimulation of macrophages by the tumour antigens. Keywords : Intracranial tumour, tumour necrosis factor, interieukin-2