Biology and Molecular Pathogenesis of Mature T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) constitute a highly heterogeneous group of hematological diseases with complex clinical and molecular features consistent with the diversity of the T-cell type from which they originate. In the past several years, the systematic implementation of high-throughput genomic technologies for the analysis of T-cell malignancies has supported an exponential progress in our understanding of the genetic drivers of oncogenesis and unraveled the molecular complexity of these diseases. Recent findings have helped redefine the classification of T-cell malignancies and provided novel biomarkers to improve diagnosis accuracy and analyze the response to therapy. In addition, multiple novel targeted therapies including small-molecule inhibitors, antibody-based approaches, and immunotherapy have shown promising results in early clinical analysis and have the potential to completely change the way T-cell malignancies have been treated traditionally.

First-in-class inhibitor of the T cell receptor for the treatment of autoimmune diseases

Modulating T cell activation is critical for treating autoimmune diseases but requires avoiding concomitant opportunistic infections. Antigen binding to the T cell receptor (TCR) triggers the recruitment of the cytosolic adaptor protein Nck to a proline-rich sequence in the cytoplasmic tail of the TCR's CD3ε subunit. Through virtual screening and using combinatorial chemistry, we have generated an orally available, low-molecular weight inhibitor of the TCR-Nck interaction that selectively inhibits TCR-triggered T cell activation with an IC₅₀ (median inhibitory concentration) ~1 nM. By modulating TCR signaling, the inhibitor prevented the development of psoriasis and asthma and, furthermore, exerted a long-lasting therapeutic effect in a model of autoimmune encephalomyelitis. However, it did not prevent the generation of a protective memory response against a mouse pathogen, suggesting that the compound might not exert its effects through immunosuppression. These results suggest that inhibiting an immediate TCR signal has promise for treating a broad spectrum of human T cell-mediated autoimmune and inflammatory diseases.

Maintenance of immune tolerance by Foxp3+ regulatory T cells requires CD69 expression

Although FoxP3(+) regulatory T cells are key players in the maintenance of immune tolerance and autoimmunity, the lack of specific markers constitute an obstacle to their use for immunotherapy protocols. In this study, we have investigated the role of the C-type lectin receptor CD69 in the suppressor function of Tregs and maintenance of immune tolerance towards harmless inhaled antigens. We identified a novel FoxP3(+)CD69(+) Treg subset capable to maintain immune tolerance and protect to developing inflammation. Although CD69(+) and CD69(-)FoxP3(+) Tregs exist in homeostasis, only CD69-expressing Tregs express high levels of CTLA-4, ICOS, CD38 and GITR suppression-associated markers, secrete high amounts of TGFβ and have potent suppressor activity. This activity is regulated by STAT5 and ERK signaling pathways and is impaired by antibody-mediated down-regulation of CD69 expression. Moreover, immunotherapy with FoxP3(+)CD69(+) Tregs restores the homeostasis in Cd69(-/-) mice, that fail to induce tolerance, and is also highly proficient in the prevention of inflammation. The identification of the FoxP3(+)CD69(+) Treg subset paves the way toward the development of new therapeutic strategies to control immune homeostasis and autoimmunity.

[Lung eosinophilic syndrome: clinical presentation and cases report]

INTRODUCTION

Pulmonary eosinophilia syndrome is characterized by a group of diseases that present clinical-radiological conditions, pulmonary eosinophilia or peripheral lung parenchyma in its evolution. We described the clinical and radiological presentation.

METHODS

Retrospective descriptive analysis of medical records of 7 patients between 2007 and 2010.

RESULTS

The highest numbers of cases were observed in women, with peripheral eosinophilia with values between 550 and 10,000 cells/mm3. The more frequent signs and symptoms were cough, dyspnea, fever and wheezing. The more prevalent radiological findings were alveolar interstitial and alveolar pattern. At CT scan, the most frequent pattern was ground glass. The main diagnoses made were acute and chronic eosinophilic pneumonia in equal proportions, both with response to steroids.

CONCLUSIONS

The pulmonary eosinophilia syndrome shares common features with clinical and radiological entities most prevalent, particularly community-adquired pneumonia.

[Superior Cava Venous syndrome as presentation of neoplasic disease]

Superior Cava Venous Syndrome (SVCS) encompasses a constellation of signs and symptoms resulting from partial or complete obstruction of blood flow through the superior vena cava (SVC) to the right atrium. Thrombosis can be caused by intrinsic (primary) or extrinsic compression (with or without secondary thrombosis). The causes of SVCS can be grouped according to their etiology in non-neoplastic and neoplastic. The causes malignant correspond to 65-90% of them, thrombosis and nonmalignant conditions are another causes. The presentation may be acute, clinically characterized by dyspnea and a characteristic triad (facial, neck and arms edema, cyanosis and collateral circulation). Early detection improves prognosis and is based on clinical data and imaging studies. We describe 8 cases where the SVCS was the first manifestation of neoplastic diseases. Patients were predominantly of middle-aged, male, without association with consumption of tobacco and lymphoma was most frequent diagnosis.

Eukaryotic elongation factor 2 controls TNF-α translation in LPS-induced hepatitis

Bacterial LPS (endotoxin) has been implicated in the pathogenesis of acute liver disease through its induction of the proinflammatory cytokine TNF-α. TNF-α is a key determinant of the outcome in a well-established mouse model of acute liver failure during septic shock. One possible mechanism for regulating TNF-α expression is through the control of protein elongation during translation, which would allow rapid cell adaptation to physiological changes. However, the regulation of translational elongation is poorly understood. We found that expression of p38γ/δ MAPK proteins is required for the elongation of nascent TNF-α protein in macrophages. The MKK3/6-p38γ/δ pathway mediated an inhibitory phosphorylation of eukaryotic elongation factor 2 (eEF2) kinase, which in turn promoted eEF2 activation (dephosphorylation) and subsequent TNF-α elongation. These results identify a new signaling pathway that regulates TNF-α production in LPS-induced liver damage and suggest potential cell-specific therapeutic targets for liver diseases in which TNF-α production is involved.

[Nutrition and chronic alcohol abuse]

Many patients with chronic alcohol abuse present a clinical picture of malnourishment either because of reduced usual intake of essential nutrients or because alcohol precludes an appropriate digestion and absorption of the different essential elements, vitamins, and minerals. A usual example is vitamin A deficiency in these patients. Besides, ethanol metabolic pathways themselves (through the ADH and the MEOS system) generate toxic intermediate products (acetaldehyde, free radicals) interfering with normal metabolism of essential elements, mainly lipids, leading to cellular damage through lipid peroxidation mechanisms and impairment of the membrane fluidity, fat deposits (hepatocellular steatosis), inflammation secondary to oxidative stress and proinflammatory cytokines, activation of stellate cells, fibrogenesis, etc. Nutritional supports may be effective to improve alcoholic liver disease. A balanced diet, vitamin supplements, and pharmacological therapy with antioxidants in order to recover depleted glutathione deposits are recommended. It is paramount that these patients have a multidisciplinary clinical approach to resolve the problem of alcohol dependency.

[Extensive condyloma acuminata of the penis successfully treated with 5% imiquimod cream]

Infection by HPV is considered one of the most frequent causes of sexually transmitted infections. Multiple forms of treatment have been used that vary in their effectiveness. We describe 2 patients with Extensive Condyloma Acuminata in the penis successfully treated with treated with 5% Imiquimod cream.

[Effectiveness of endoscopic sclerotherapy in the treatment of bleeding esophageal varices]

92 patients to whom urgent endoscopy and sclerotherapy of esophageal varices was performed are studied retrospectively. After the bleeding episode, elective sclerosis sessions were performed to eradicate varices, to prevent hemorrhagic complications and post-sclerotic stenosis somatostatin, H2 antagonists and sucralfate were administered. The Total number of sessions was 331, with a mean of 3.6 per patient (range 1-10). Immediate hemostasis was achieved in 93% of patients, with an early relapse in 10.4% of them. Hemorrhagic relapse two years following therapy was 35.8%. Mortality was 41%; 8% of the decreased patients belonged to Child's A functional grade, 24% belonged to B; and 68% to C. There was a 44% of complications, but only one death was due to the technique. No patient developed symptomatic stenosis neither hemorrhage secondary to esophageal ulceration. We conclude that endoscopic sclerotherapy is one of the principal therapeutic options in the hemorrhage due to esophageal varices, although new studies are necessary to define the role of somatostatin and H2 antagonists in the prophylaxis of complications.