Purpose: Patients with malignant glioma suffer global compromise of their cellular immunity, characterized by dramatic reductions in CD4 + T cell numbers and function. We have previously shown that increased regulatory T cell (T reg ) fractions in these patients explain T-cell functional deficits. Our murine glioma model recapitulates these findings. Here, we investigate the effects of systemic CTLA-4 blockade in this model. Experimental Design: A monoclonal antibody (9H10) to CTLA-4 was employed against wellestablished glioma. Survival and risks for experimental allergic encephalomyelitis were assessed, as were CD4 + T cell numbers and function in the peripheral blood, spleen, and cervical lymph nodes. The specific capacities for anti-CTLA-4 to modify the functions of regulatory versus CD4 + CD25À responderTcells were evaluated. Results: CTLA-4 blockade confers long-term survival in 80 % of treated mice, without eliciting experimental allergic encephalomyelitis. Changes to the CD4 compartment were reversed, as anti-CTLA-4 reestablishes normal CD4 counts and abrogates increases in CD4 À T cells from treated mice show improved proliferative responses and resistance to T reg -mediated suppression, whereas T regs from the same mice remain anergic and exhibit no restriction of their suppressive capacity. Conclusions: CTLA-4 blockade is a rational means of reversing glioma-induced changes to the CD4 compartment and enhancing antitumor immunity. These benefits were attained through the conferment of resistance toT reg -mediated suppression, and not through direct effects onT regs .

Purpose: Spread to the central nervous system (CNS) and the leptomeninges is a frequent complication of systemic cancers that is associated with serious morbidity and high mortality. We have evaluated a novel therapeutic approach against CNS complications of breast cancer based on the human neuropathogen poliovirus (PV).Experimental Design: Susceptibility to PV infection and ensuing rapid cell lysis is mediated by the cellular receptor of PV, CD155. We evaluated CD155 expression in several human breast tumor tissue specimens and cultured breast cancer cell lines. In addition, we tested an oncolytic PV recombinant for efficacy in xenotransplantation models of neoplastic meningitis and cerebral metastasis secondary to breast cancer.Results: We observed that breast cancer tissues and cell lines derived thereof express CD155 at levels mediating exquisite sensitivity toward PV-induced oncolysis in the latter. An association with the immunoglobulin superfamily molecule CD155 renders breast cancer a likely target for oncolytic PV recombinants. This assumption was confirmed in xenotransplantation models for neoplastic meningitis or solitary cerebral metastasis, where local virus treatment dramatically improved survival.Conclusions: Our findings suggest oncolytic PV recombinants as a viable treatment option for CNS complications of breast cancer.

Purpose: The toxicity and antitumor activity of regional intrathecal delivery of an oncolytic recombinant poliovirus, PVS-RIPO, was evaluated in rodent models of glioblastoma multiforme neoplastic meningitis. Experimental Design: To evaluate for toxicity, PVS-RIPO was administered into the spinal cord of transgenic mice that express the human poliovirus receptor, CD155, and into the intrathecal space of athymic rats without tumor. To evaluate efficacy, two different doses of PVS-RIPO were administered intrathecally 3 days after athymic rats were inoculated intrathecally with an aggressive human glioblastoma multiforme xenograft. Results: No clinical or histologic evidence of toxicity was found. In efficacy studies, median survival was increased by 174.47% from 8.5 days in the group treated with UV light-inactivated virus to 15 days in the rats treated with 1.0 Â 10 7 plaque-forming units (pfu) of PVS-RIPO (P < 0.0001).A similar increase in median survival was seen in the group receiving 1.0 Â 10 9 pfu PVS-RIPO (P < 0.0001); however, there was no statistically significant dose-response relationship (P = 0.345). In addition, 1 of 10 rats in lower-dose PVS-RIPO^treated group and 3 of 10 rats in higher-dose PVS-RIPO^treated group survived >60 days after tumor cell inoculation and had no evidence of residual tumor at autopsy. Conclusion: These results suggest that intrathecal treatment with PVS-RIPO may be useful for treatment of neoplastic meningitis in patients with glioblastoma multiforme and provides a rationale for clinical trials in this area.

The occurrence of neurogenic pulmonary edema (NPE) associated with subarachnoid hemorrhage (SAH) due to ruptured aneurysm was analyzed in 48 consecutive patients. Correlations of the location of the aneurysm, clinical grade, amount of subarachnoid clot, and severity of NPE were examined. NPE was observed in 29.4% of all SAH cases, but the incidence was significantly higher in cases of ruptured vertebral artery (VA) aneurysm. Clinical grade, severity of NPE, and deformation of the medulla oblongata were studied in the five cases of ruptured VA aneurysm. Deformation of the ventrolateral medulla oblongata was observed in all patients. Asymmetry index of the medulla oblongata measured on the axial computed tomography scan was correlated with the severity of NPE. Severity of NPE tended to correlate with deformation of the medulla oblongata. NPE associated with ruptured VA aneurysm is caused by deformation of the ventrolateral site of the medulla oblongata by the localized hemorrhage.