Hematopoietic expression of a chimeric murine-human CALR oncoprotein allows the assessment of anti-CALR antibody immunotherapies in vivo.

Myeloproliferative neoplasms (MPNs) are characterized by a pathologic expansion of myeloid lineages. Mutations in JAK2, CALR and MPL genes are known to be three prominent MPN disease drivers. Mutant CALR (mutCALR) is an oncoprotein that interacts with and activates the thrombopoietin receptor (MPL) and represents an attractive target for targeted therapy of CALR mutated MPN. We generated a transgenic murine model with conditional expression of the human mutant exon 9 (del52) from the murine endogenous Calr locus. These mice develop essential thrombocythemia like phenotype with marked thrombocytosis and megakaryocytosis. The disease exacerbates with age showing prominent signs of splenomegaly and anemia. The disease is transplantable and mutCALR stem cells show proliferative advantage when compared to wild type stem cells. Transcriptome profiling of hematopoietic stem cells revealed oncogenic and inflammatory gene expression signatures. To demonstrate the applicability of the transgenic animals for immunotherapy, we treated mice with monoclonal antibody raised against the human mutCALR. The antibody treatment lowered platelet and stem cell counts in mutant mice. Secretion of mutCALR did not constitute a significant antibody sink. This animal model not only recapitulates human MPN but also serves as a relevant model for testing immunotherapeutic strategies targeting epitopes of the human mutCALR.

Combined Effects of Inflammatory Status and Carotid Atherosclerosis: A 12-Year Follow-Up Study.

BACKGROUND AND PURPOSE: Inflammatory responses play a key role in atherogenesis. The aim of this study was to assess the prognostic value of hsCRP (high-sensitivity C-reactive protein) and to evaluate whether degree of carotid stenosis and serum levels of hsCRP jointly predict long-term mortality in asymptomatic patients with carotid atherosclerosis. METHODS: One thousand sixty-five patients with neurological asymptomatic carotid atherosclerosis as evaluated by duplex sonography were prospectively followed for cause-specific mortality. RESULTS: During a median of 11.81 years, a total of 549 deaths, including 362 cardiovascular deaths, were recorded. The risk of all-cause and cardiovascular mortality significantly increased in patients with elevated serum levels of hsCRP (the adjusted hazard ratio for cardiovascular mortality per increase of 1 mg/dL of hsCRP levels was 1.47; P<0.001). Patients with a high degree of carotid stenosis and increased hsCRP levels were particularly at risk of adverse outcome. Patients with carotid narrowing over 50% and hsCRP levels >0.29 mg/dL (=median) had nearly twice as high a risk of cardiovascular mortality compared with patients with carotid stenosis of <50% and hsCRP levels <0.29 mg/dL (adjusted hazard ratio 1.89; P<0.001). Improvement in risk stratification with combined assessment of carotid stenosis and hsCRP was confirmed by an improvement of the continuous net reclassification improvement with 18% for all-cause mortality and 15% for cardiovascular mortality compared with the degree of carotid stenosis alone (P<0.01). CONCLUSIONS: Measurement of hsCRP in combination with ultrasound investigations of the carotid arteries at a single time point provides additional prognostic information for patients with asymptomatic carotid atherosclerosis.

Increased immunopotency of monocyte derived dendritic cells from patients with optic neuritis is inhibited in vitro by simvastatin.

Multiple sclerosis (MS) is an autoimmune disease where myelin-reactive lymphocytes and their activation depend on interactions with antigen presenting cells (APCs). Dendritic cells (DC) are professional APCs dependent on maturation to attain full T-cell priming capacity. The immunomodulatory properties of simvastatin influence the function of both T cells and APCs and could thus be a potential therapy for MS. The phenotype of myeloid DC in untreated patients with monosymptomatic optic neuritis (ON) was determined by flow cytometry and the impact of simvastatin on the function of myeloid DC derived from peripheral blood mononuclear cells (PBMC) was analysed in vitro. DC from ON patients had more mature phenotype compared with healthy controls (HC). Particularly the fraction of DC expressing CD1a and CD80 was significantly higher in ON than in HC (P<0.05). Addition of 10 muMu simvastatin significantly inhibited the maturation of DC in the ON group. Furthermore, ON derived DC induced stronger T-cell proliferation in the mixed leukocyte reaction (MLR), and simvastatin solely inhibited this proliferation of T-cells in the ON group and not in HC. In conclusion DC from ON patients have a more mature phenotype and an increased stimulatory capacity. Simvastatin has an inhibitory effect on the differentiation and maturation of DC, and selectively reduce the T-cell proliferation induced by DC from patients with ON. The results from these in vitro assays suggest potential beneficial inhibitory effects of Simvastatin in the inflammation in ON and early MS, but we need more clinical trials to confirm it.