Isolated angiitis of the CNS frequently recurs in children

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Primary angiitis of the central nervous system: neurologic deterioration despite treatment.

Primary angiitis of the central nervous system (PACNS) is an idiopathic vasculitis confined to the central nervous system. In children with PACNS, small-vessel (SV) involvement is characterized clinically by progressive neurologic symptoms, multifocal lesions on brain imaging, occasional pseudo-tumor presentation, and normal angiogram results in most patients. Small case series of patients with SV PACNS with short follow-up usually reveal favorable outcomes in children treated with immunosuppressive therapy. We report here the cases of 3 children with biopsy-confirmed SV PACNS and long-term follow-up who developed different patterns of neurologic deterioration despite immunosuppressive therapy. One patient had transient ischemic attacks shortly after initiation of corticosteroid treatment. Early ischemic events probably result from residual thrombogenicity or residual inflammation of recently affected vessels, which supports the use of antiplatelet agents and suggests potential benefits of stronger immunosuppressive therapy. In contrast, the other 2 patients had later neurologic deterioration after corticosteroid withdrawal, which suggests failure of initial immunosuppressant treatment and the need for stronger agents, longer treatment duration, or both. All patients responded to long-term treatment with corticosteroids combined with cytotoxic agents. This particular combination is probably indicated in many cases of SV PACNS, including those with neurologic deterioration that occurs during maintenance corticotherapy or after corticosteroid withdrawal. In 1 case, SV PACNS recurred several years after discontinuation of combination therapy. Long-term relapses may reflect intrinsic predispositions to SV PACNS rather than treatment failure. These cases highlight different chronological patterns of neurologic deterioration despite immunosuppressive therapy, which supports the relevance of monitoring clinical, laboratory, and radiologic responses to treatment and of long-term follow-up of patients with SV PACNS.Case ReportsJournal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Integrative single‐cell expression and functional studies unravels a sensitization to cytarabine‐based chemotherapy through HIF pathway inhibition in AML leukemia stem cells

Abstract Relapse remains a major challenge in the clinical management of acute myeloid leukemia (AML) and is driven by rare therapy‐resistant leukemia stem cells (LSCs) that reside in specific bone marrow niches. Hypoxia signaling maintains cells in a quiescent and metabolically relaxed state, desensitizing them to chemotherapy. This suggests the hypothesis that hypoxia contributes to the chemoresistance of AML‐LSCs and may represent a therapeutic target to sensitize AML‐LSCs to chemotherapy. Here, we identify HIFhigh and HIFlow specific AML subgroups (inv(16)/t(8;21) and MLLr, respectively) and provide a comprehensive single‐cell expression atlas of 119,000 AML cells and AML‐LSCs in paired diagnostic‐relapse samples from these molecular subgroups. The HIF/hypoxia pathway signature is attenuated in AML‐LSCs compared with more differentiated AML cells but is more expressed than in healthy hematopoietic cells. Importantly, chemical inhibition of HIF cooperates with standard‐of‐care chemotherapy to impair AML growth and to substantially eliminate AML‐LSCs in vitro and in vivo. These findings support the HIF pathway in the stem cell‐driven drug resistance of AML and unravel avenues for combinatorial targeted and chemotherapy‐based approaches to specifically eliminate AML‐LSCs