New insights into the Immune TME of adult-type diffuse gliomas

International audiencePurpose of review Adult-type diffuse gliomas are highly heterogeneous tumors. Bulk transcriptome analyses suggested that the composition of the tumor microenvironment (TME) corresponds to genetic and clinical features. In this review, we highlight novel findings on the intratumoral heterogeneity of IDH-wildtype and IDH-mutant gliomas characterized at single-cell resolution, and emphasize the mechanisms shaping the immune TME and therapeutic implications. Recent findings Emergent evidence indicates that in addition to genetic drivers, epigenetic mechanisms and microenvironmental factors influence the glioma subtypes. Interactions between glioma and immune cells contribute to immune evasion, particularly in aggressive tumors. Spatial and temporal heterogeneity of malignant and immune cell subpopulations is high in recurrent gliomas. IDH-wildtype and IDH-mutant tumors display distinctive changes in their myeloid and lymphoid compartments, and D-2HG produced by IDH-mutant cells impacts the immune TME

Brain Metabolic Alterations in Seropositive Autoimmune Encephalitis: An ¹⁸F-FDG PET Study

Introduction: Autoimmune encephalitis (AE) diagnosis and follow-up remain challenging. Brain 18F-fluoro-deoxy-glucose positron emission tomography (FDG PET) has shown promising results in AE. Our aim was to investigate FDG PET alterations in AE, according to antibody subtype. Methods: We retrospectively included patients with available FDG PET and seropositive AE diagnosed in our center between 2015 and 2020. Brain PET Z-score maps (relative to age matched controls) were analyzed, considering metabolic changes significant if |Z-score| ≥ 2. Results: Forty-six patients were included (49.4 yrs [18; 81]): 13 with GAD autoantibodies, 11 with anti-LGI1, 9 with NMDAR, 5 with CASPR2, and 8 with other antibodies. Brain PET was abnormal in 98% of patients versus 53% for MRI. The most frequent abnormalities were medial temporal lobe (MTL) and/or striatum hypermetabolism (52% and 43% respectively), cortical hypometabolism (78%), and cerebellum abnormalities (70%). LGI1 AE tended to have more frequent MTL hypermetabolism. NMDAR AE was prone to widespread cortical hypometabolism. Fewer abnormalities were observed in GAD AE. Striatum hypermetabolism was more frequent in patients treated for less than 1 month (p = 0.014), suggesting a relation to disease activity. Conclusion: FDG PET could serve as an imaging biomarker for early diagnosis and follow-up in AE

SARS-CoV-2 infection in patients with primary central nervous system lymphoma

International audienceBackgroundCancer patients may be at higher risk for severe coronavirus infectious disease-19 (COVID-19); however, the outcome of Primary Central Nervous System Lymphoma (PCNSL) patients with SARS-CoV-2 infection has not been described yet. Methods We conducted a retrospective study within the Lymphomes Oculo-Cérébraux national network (LOC) to assess the clinical characteristics and outcome of SARS-CoV-2 infection in PCNSL patients (positive real-time polymerase chain reaction of nasopharyngeal swab or evocative lung computed tomography scan). We compared clinical characteristics between patients with severe (death and/or intensive care unit admission) and mild disease. Results Between March and May 2020, 13 PCNSL patients were diagnosed with SARS-CoV-2 infection, 11 (85%) of whom were undergoing chemotherapy at the time of infection. The mortality rate was 23% (3/13), and two additional patients (15%) required mechanical ventilation. Two patients (15%) had no COVID-19 symptoms. History of diabetes mellitus was more common in severe patients (3/5 vs 0/8, p = 0.03). Two patients recovered from COVID-19 after mechanical ventilation during more than two weeks and resumed chemotherapy. In all, chemotherapy was resumed after COVID-19 recovery in nine patients (69%) after a median delay of 16 days (range 3-32), none of whom developed unusual chemotherapy complication nor SARS-Cov2 reactivation. Conclusion This preliminary analysis suggests that, while being at higher risk be for severe illness, PCNSL patients with COVID-19 might be treated maximally especially if they achieved oncological response at the time of SARS-CoV-2 infection. Chemotherapy might be resumed without prolonged delay in PCNSL patients with COVID-19

Impact of severe acute respiratory syndrome coronavirus-2 infection on the outcome of primary central nervous system lymphoma treatment: A study of the International PCNSL Collaborative Group

To optimise management of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection identifying high-risk patients and maintaining treatment dose intensity is an important issue in patients with aggressive lymphomas. In the present study, we report on the presentation, management, and outcome of an international series of 91 patients with primary central nervous system lymphoma and SARS-CoV-2 infection. SARS-CoV-2 was diagnosed before/during first-line treatment in 64 patients, during follow-up in 21, and during salvage therapy in six. Among the 64 patients infected before/during first-line chemotherapy, 38 (59%) developed pneumonia and 26 (41%) did not clear the virus. Prolonged exposure to steroids before viral infection and/or treatment with high-dose cytarabine favoured pneumonia development and virus persistence and were associated with poorer survival; 81% of patients who did not clear virus died early from coronavirus disease 2019 (COVID-19). Vaccination was associated with lower pneumonia incidence and in-hospital mortality. Chemotherapy was initiated/resumed in 43 (67%) patients, more commonly among patients who did not develop pneumonia, cleared the virus, or did not receive steroids during infection. Chemotherapy resumption in patients with viral persistence should be indicated cautiously as it was associated with a poorer survival (6-month, 70% and 87%, p = 0.07). None of the 21 patients infected during follow-up died from COVID-19, requiring similar measures as infected subjects in the general population

Integrated proteogenomic characterization of glioblastoma evolution

The evolutionary trajectory of glioblastoma (GBM) is a multifaceted biological process that extends beyond genetic alterations alone. Here, we perform an integrative proteogenomic analysis of 123 longitudinal glioblastoma pairs and identify a highly proliferative cellular state at diagnosis and replacement by activation of neuronal transition and synaptogenic pathways in recurrent tumors. Proteomic and phosphoproteomic analyses reveal that the molecular transition to neuronal state at recurrence is marked by post -translational activation of the wingless -related integration site (WNT)/ planar cell polarity (PCP) signaling pathway and BRAF protein kinase. Consistently, multi-omic analysis of patient -derived xenograft (PDX) models mirror similar patterns of evolutionary trajectory. Inhibition of B-raf proto-oncogene (BRAF) kinase impairs both neuronal transition and migration capability of recurrent tumor cells, phenotypic hallmarks of post -therapy progression. Combinatorial treatment of temozolomide (TMZ) with BRAF inhibitor, vemurafenib, significantly extends the survival of PDX models. This study provides comprehensive insights into the biological mechanisms of glioblastoma evolution and treatment resistance, highlighting promising therapeutic strategies for clinical intervention