Langerhans cell histiocytosis (LCH) and the non-LCH neoplasm Erdheim-Chester disease (ECD) are heterogeneous neoplastic disorders marked by infiltration of pathologic macrophage-, dendritic cell-, or monocyte-derived cells in tissues driven by recurrent mutations activating MAPK signaling. Although recent data indicate that at least a proportion of LCH and ECD patients have detectable activating kinase mutations in circulating hematopoietic cells and bone marrow-based hematopoietic progenitors, functional evidence of the cell of origin of histiocytosis from actual patient materials has long been elusive. Here, we provide evidence for mutations in MAPK signaling intermediates in CD34 cells from patients with ECD and LCH/ECD, including detection of shared origin of LCH and acute myelomonocytic leukemia driven by -mutant CD34 cell progenitors in one patient. We also demonstrate functional self-renewal capacity for CD34 cells to drive the development of histiocytosis in xenotransplantation assays in vivo. These data indicate that the cell of origin of at least a proportion of patients with systemic histiocytoses resides in hematopoietic progenitor cells prior to committed monocyte/macrophage or dendritic cell differentiation and provide the first example of a patient-derived xenotransplantation model for a human histiocytic neoplasm.

No abstract

No abstract

Background: Behçet’s disease (BD) is a rare form of vasculitis involving both veins and arteries of all calibers. Psychological symptoms and cognitive impairment appear to be frequent, but few data are available. Methods: All consecutive patients in our center fulfilling the 2013 BD criteria underwent a psychometric evaluation with auto- (SCL-90-R and Modified Fatigue Index) and hetero-questionnaires (MINI). A standardized test battery assessed cognitive dysfunction. Data were correlated with BD activity as well as quality of life (SF-36). Results: We included 20 consecutive patients (16 men, four women) with a median [IQR] age of 38 (30.0–45.5) and a median disease duration of 7 years (1.8–11.0). Five patients had an abnormal brain MRI. The SCL-90-R questionnaire highlighted eight psychopathological profiles (42.1%) that correlated with altered quality of life and more severe fatigue. The most frequent symptoms were anxiety (9/19, 47.4%), somatization (8/19, 42.1%) and phobia (5/19, 26.3%). Psychopathological symptoms appeared to be more severe, but not more frequent, in neuro-Behçet’s patients. Based on standardized cognitive evaluation, nine patients had cognitive impairment defined by three or more altered tests. Notably, 6/9 patients did not have any complaint of memory loss and were thus considered ansognostic. Conclusion: Cognitive involvement was significantly associated with BD activity score (BSAS) but not with brain MRI abnormalities.