Patients with malignant gliomas who had undergone BCG inoculations were injected intratumorally with PPD to induce an intratumoral delayed hypersensitivity reaction. Histopathological examination of the tumor before and after PPD injections revealed that chronic inflammatory responses were increased after injection in four of the five patients. In no case, however, was the response more than moderate, and in no case did the inflammatory response encompass the tumor at its peripheral margins. Intracerebral delayed hypersensitivity reactions were evoked in humans with acceptable morbidity. The mild reactions evoked did not cause detectable tumor regressions.
Cancer 39 : 133 1 -1336, 1 9 7 7 .
NTRATUMORAL DELAYED HYPERSENSITIVITY RE-I actions induce regressions of a variety of human neoplasms, primarily malignant cutaneous neoplasms.4.9~12~13 In addition, chronic inflammatory reactions have been shown to induce regressions of intradermal hepatocarcinomas in guinea pigs.3 W e have previously demonstrated that intracerebral delayed hypersensitivity reactions can be evoked in the cerebral hemispheres of normal rhesus monkeys, without significant alterations in the animals' neurological conditions. Attempts to induce intratumoral delayed hypersensitivity reactions were subsequently undertaken within the context of a clinical trial of immunochemotherapy of malignant gliomas. This study reports the clinical and histopathological evaluation of ten patients with malignant gliomas, five of whom were injected intratumorally with antigen.
MATERIALS AND METHODS
Patients
Ten patients, ranging in age from 6-59 years, with biopsy-proved malignant astrocytomas, were referred to the National Institutes of