Host response to injury and infection is IntroductionSerum amyloid A (SAA) is a major acute-phase protein released to circulation in response to infection and injury. Within the first 24 to 36 hours after infection or injury, the blood concentration of SAA can increase by as much as 1000-fold over basal level, reaching a concentration of 80 M or 1 mg/mL. 1,2 The liver is a major source of acute-phase SAA, but extrahepatic expression of SAA has also been documented and is known to involve cells of atherosclerotic lesions, that is, smooth muscle cells, endothelial cells, and monocytes/macrophages. 3,4 Inflammatory cytokines such as interleukin 1␤ (IL-1␤), tumor necrosis factor ␣ (TNF-␣), and IL-6 are potent inducers of SAA expression by hepatocytes and, to various degrees, by macrophages and synoviocytes. 2,[5][6][7] In circulation, SAA is associated with high-density lipoproteins (HDLs) at lower concentrations, but it dissociates from HDLs at higher concentrations. 8,9 Free SAA is also found in the inflammatory sites, 3,4 suggesting a role of SAA in local inflammation.The marked increase of SAA has been used as an important indicator for diagnosis and prognosis of inflammatory diseases. 7,10 In addition, SAA is implicated as both a beneficial and harmful factor in the inflammatory process. Potential beneficial roles include reverse transport of cholesterol at sites of inflammation, through its ability to displace cholesterol from HDL. 11,12 With respect to being a harmful factor, SAA is the precursor of amyloid A, the deposit of which causes amyloidosis. 7,13 The findings that SAA is produced locally in atherosclerotic lesions and in arthritic joints suggest a potential role of this acute-phase protein in chronic inflammatory diseases such as atherosclerotic and rheumatoid arthritis. [13][14][15] Despite these important findings, a precise function of SAA in acute inflammation has not been defined. It is notable that a number of studies suggest a link between SAA and leukocyte infiltration. SAA is chemotactic to leukocytes including monocytes, mast cells, and T lymphocytes at concentrations attained in the blood during an acute-phase response. [16][17][18] These early observations have led to the recent identification of a cell surface receptor that mediates SAA-stimulated chemotaxis in monocytes. 19 There is also accumulating evidence suggesting that SAA possesses cytokinelike activities and is able to induce the production of matrix metalloproteinases (MMPs), 20 cytokines, and cytokine receptors including IL-1␤, interleukin-1 receptor antagonist (IL-1ra), and soluble TNF-␣ type II receptor (sTNFr-II). 21 Neutrophils that are stimulated by SAA for 24 hours release TNF-␣, IL-1␤, and IL-8 into culture medium. 22 However, it is not clear whether this is a primary response to SAA or a secondary response to other secreted cytokines because of the long incubation time. The receptor that mediates this function of SAA has not been identified.In this study, we investigated whether SAA induces primary cytokine responses i...

Induced secretion of acute-phase serum amyloid A (SAA) is a host response to danger signals and a clinical indication of inflammation. The biological functions of SAA in inflammation have not been fully defined, although recent reports indicate that SAA induces proinflammatory cytokine expression. We now show that TLR2 is a functional receptor for SAA. HeLa cells expressing TLR2 responded to SAA with potent activation of NF-κB, which was enhanced by TLR1 expression and blocked by the Toll/IL-1 receptor/resistance (TIR) deletion mutants of TLR1, TLR2, and TLR6. SAA stimulation led to increased phosphorylation of MAPKs and accelerated IκBα degradation in TLR2-HeLa cells, and results from a solid-phase binding assay showed SAA interaction with the ectodomain of TLR2. Selective reduction of SAA-induced gene expression was observed in tlr2−/− mouse macrophages compared with wild-type cells. These results suggest a potential role for SAA in inflammatory diseases through activation of TLR2.

The coexistence of inflammatory cells with markers of apoptotic vascular cell death in the media of ascending aortas with aneurysms and type A dissections raises the possibility that activated T cells and macrophages may contribute to the elimination of smooth muscle cells and degradation of the matrix associated with thoracic aortic aneurysms and dissections.

• Pembrolizumab was first shown to be clinically active in CLL patients with RT.• PD-1 and PD-L1 expression in tumor microenvironment are promising biomarkers to select RT patients for PD-1 blockade.Chronic lymphocytic leukemia (CLL) patients progressed early on ibrutinib often develop Richter transformation (RT) with a short survival of about 4 months. Preclinical studies suggest that programmed death 1 (PD-1) pathway is critical to inhibit immune surveillance in CLL. This phase 2 study was designed to test the efficacy and safety of pembrolizumab, a humanized PD-1-blocking antibody, at a dose of 200 mg every 3 weeks in relapsed and transformed CLL. Twenty-five patients including 16 relapsed CLL and 9 RT (all proven diffuse large cell lymphoma) patients were enrolled, and 60% received prior ibrutinib. Objective responses were observed in 4 out of 9 RT patients (44%) and in 0 out of 16 CLL patients (0%). All responses were observed in RT patients who had progression after prior therapy with ibrutinib. After a median follow-up time of 11 months, the median overall survival in the RT cohort was 10.7 months, but was not reached in RT patients who progressed after prior ibrutinib. Treatment-related grade 3 or above adverse events were reported in 15 (60%) patients and were manageable. Analyses of pretreatment tumor specimens from available patients revealed increased expression of PD-ligand 1 (PD-L1) and a trend of increased expression in PD-1 in the tumor microenvironment in patients who had confirmed responses. Overall, pembrolizumab exhibited selective efficacy in CLL patients with RT. The results of this study are the first to demonstrate the benefit of PD-1 blockade in CLL patients with RT, and could change the landscape of therapy for RT patients if further validated. This trial was registered at www.clinicaltrials.gov as #NCT02332980. (Blood. 2017;129(26):3419-3427)

BackgroundAlterations in DNA methylation in cancer include global hypomethylation and gene-specific hypermethylation. It is not clear whether these two epigenetic errors are mechanistically linked or occur independently. This study was performed to determine the relationship between DNA hypomethylation, hypermethylation and microsatellite instability in cancer.Methodology/Principal FindingsWe examined 61 cancer cell lines and 60 colorectal carcinomas and their adjacent tissues using LINE-1 bisulfite-PCR as a surrogate for global demethylation. Colorectal carcinomas with sporadic microsatellite instability (MSI), most of which are due to a CpG island methylation phenotype (CIMP) and associated MLH1 promoter methylation, showed in average no difference in LINE-1 methylation between normal adjacent and cancer tissues. Interestingly, some tumor samples in this group showed increase in LINE-1 methylation. In contrast, MSI-showed a significant decrease in LINE-1 methylation between normal adjacent and cancer tissues (P<0.001). Microarray analysis of repetitive element methylation confirmed this observation and showed a high degree of variability in hypomethylation between samples. Additionally, unsupervised hierarchical clustering identified a group of highly hypomethylated tumors, composed mostly of tumors without microsatellite instability. We extended LINE-1 analysis to cancer cell lines from different tissues and found that 50/61 were hypomethylated compared to peripheral blood lymphocytes and normal colon mucosa. Interestingly, these cancer cell lines also exhibited a large variation in demethylation, which was tissue-specific and thus unlikely to be resultant from a stochastic process.Conclusion/SignificanceGlobal hypomethylation is partially reversed in cancers with microsatellite instability and also shows high variability in cancer, which may reflect alternative progression pathways in cancer.

The major disease processes affecting the aorta are aortic aneurysms and dissections. Aneurysms are usually described in terms of their anatomic location, with thoracic aortic aneurysms (TAAs) involving the ascending and descending aorta in the thoracic cavity and abdominal aortic aneurysms (AAAs) involving the infrarenal abdominal aorta. Both thoracic and abdominal aortas are elastic arteries, and share similarities in their physical structures and cellular components. However, thoracic and abdominal aortas differ in their biochemical properties and the origin of their vascular smooth muscle cells (VSMCs). These similarities and differences between thoracic and abdominal aortas provide the basis for the various pathologic mechanisms observed in this disease. This review focuses on the comparison of the pathologic mechanisms involved in TAA and AAA.

The acute-phase protein serum amyloid A (SAA) is commonly considered a marker for inflammatory diseases; however, its precise role in inflammation and infection, which often result in neutrophilia, remains ambiguous. In this study, we demonstrate that SAA is a potent endogenous stimulator of granulocyte colonystimulated factor (G-CSF), a principal cytokine-regulating granulocytosis. This effect of SAA is dependent on Toll-like receptor 2 (TLR2). Our data demonstrate

DNA methylation of CpG islands around gene transcription start sites results in gene silencing and plays a role in leukemia pathophysiology. Its impact in leukemia progression is not fully understood. We performed genomewide screening for methylated CpG islands and identified 8 genes frequently methylated in leukemia cell lines and in patients with acute myeloid leukemia (AML): NOR1, CDH13, p15, NPM2, OLIG2, PGR, HIN1, and SLC26A4. We assessed the methylation status of these genes and of the repetitive element LINE-1 in 30 patients with AML, both at diagnosis and relapse. Abnormal methylation was found in 23% to 83% of patients at diagnosis and in 47% to 93% at relapse, with CDH13 being the most frequently methylated. We observed concordance in methylation of several genes, confirming the presence of a hypermethylator pathway in AML. DNA methylation levels increased at relapse in 25 of 30 (83%) patients with AML. These changes represent much larger epigenetic dysregulation, since methylation microarray analysis of 9008 autosomal genes in 4 patients showed hypermethylation ranging from 5.9% to 13.6% (median 8.3%) genes at diagnosis and 8.0% to 15.2% (median 10.6%) genes in relapse (P < .001). Our data suggest that DNA methylation is involved in AML progression and provide a rationale for the use of epigenetic agents in remission maintenance. (Blood. 2008;112:1366-1373)