The prognostic value of MGMT promoter methylation in glioblastoma: A meta‐analysis of clinical trials

The DNA repair protein O6‐Methylguanine‐DNA methyltransferase (MGMT) is suggested to be associated with resistance to alkylating agents such as Temozolomide which is being used in treatment of patients with glioblastoma (GBM). Therefore, we evaluated the associations between MGMT promoter methylation and prognosis of patients with glioblastoma (GBM). Data were extracted from publications in Embase, PubMed, and the Cochrane Library. Data on overall survival (OS), progression‐free survival (PFS), and MGMT methylation status were obtained and 4,097 subjects were enrolled. Data from 34 studies showed that MGMT methylated patients had better OS, compared to GBM unmethylated patients (pooled HRs, 0.494; 95%CI 0.412–0.591; p = 0.001). Meta‐analysis of 10 eligible studies reporting on PFS, demonstrated that MGMT promoter methylation was not significantly associated with better PFS (pooled HRs, 0.653; 95%CI 0.414–1.030; p = 0.067). GBM patients with MGMT methylation were associated with longer overall survival, although this effect was not detected for PFS. Moreover, we performed further analysis in patients underwent a comprehensive imaging evaluation. This data showed a significant association with better OS and PFS, although further studies are warranted to assess the value of emerging marker in prospective setting in patients with glioblastoma as a risk stratification biomarker in clinical management of the patients.     

Inhibition of S-antigen induced experimental autoimmune uveoretinitis by oral induction of tolerance with S-antigen

The ability to prevent the expression of retinal SAg induced experimental autoimmune uveitis (EAU) in Lewis rats by oral administration of the SAg and SAg fragments was investigated. Oral administration of the SAg molecule prevented or markedly diminished the clinical appearance of SAg-induced disease as measured by ocular inflammation. Furthermore, oral administration of the SAg also markedly diminished uveitis induced by the uveitogenic M and N fragments of the SAg. M and N fragments were not effective in preventing SAg-induced EAU, although feeding the M fragment prevented disease induced by the M fragment. Oral administration of the SAg did not prevent myelin basic protein induced experimental autoimmune encephalomyelitis, whereas feeding myelin basic protein did. In vitro studies demonstrated a significant decrease in proliferative responses to the SAg in lymph node cells draining the site of immunization from fed vs nonfed animals. Furthermore, the addition of splenocytes from SAg-fed animals to cultures of a CD4+ SAg-specific cell line profoundly suppressed the cell line's response to the SAg, whereas these splenocytes had no effect on a purified protein derivative-specific cell line. The Ag-specific in vitro suppression was blocked by anti-CD8 antibody (OX-8) demonstrating that this suppression is dependent on CD8+ T-cells. These experiments demonstrate that Ag-specific immunomanipulation can be achieved in the EAU model by oral administration of the SAg and raise the possibility that such an approach may have practical clinical implications in uveitis as well as other human autoimmune diseases.