Infectious agents and inflammation. The role of microbiota in autoimmune arthritis

In higher vertebrates, mucosal sites at the border between the internal and external environments, directly interact with bacteria, viruses, and fungi. Through co-evolution, hosts developed mechanisms of tolerance or ignorance toward some infectious agents, because hosts established "gain of function" interactions with symbiotic bacteria. Indeed, some bacteria assist hosts in different functions, among which are digestion of complex carbohydrates, and absorption and supply of vitamins. There is no doubt that microbiota modulate innate and acquired immune responses starting at birth. However, variations in quality and quantity of bacterial species interfere with the equilibrium between inflammation and tolerance. In fact, correlations between gut bacteria composition and the severity of inflammation were first described for inflammatory bowel diseases and later extended to other pathologies. The genetic background, environmental factors (e.g., stress or smoking), and diet can induce strong changes in the resident bacteria which can expose the intestinal epithelium to a variety of different metabolites, many of which have unknown functions and consequences. In addition, alterations in gut permeability may allow pathogens entry, thereby triggering infection and/or chronic inflammation. In this context, a local event occurring at a mucosal site may be the triggering cause of an autoimmune reaction that eventually involves distant sites or organs. Recently, several studies attributed a pathogenic role to altered oral microbiota in rheumatoid arthritis (RA) and to gut dysbiosis in spondyloarthritis (SpA). There is also growing evidence that different drugs, such as antibiotics and immunosuppressants, can influence and be influenced by the diversity and composition of microbiota in RA and SpA patients. Hence, in complex disorders such RA and SpA, not only the genetic background, gender, and immunologic context of the individual are relevant, but also the history of infections and the structure of the microbial community at mucosal sites should be considered. Here the role of the microbiota and infections in the initiation and progression of chronic arthritis is discussed, as well as how these factors can influence a patient's response to synthetic and biologic immunosuppressive therapy

Progetto di un edificio per ristorazione in legno lamellare

Oggetto di questa tesi di Laurea Specialistica è stato la progettazione di un nuovo edificio per ristorazione situato a Rosignano Marittimo (LI). Gli obiettivi sono molteplici: dalla progettazione architettonica di massima di un luogo per la ristorazione che fornisse anche spazi di riposo e aggregazione, allo sviluppo di un progetto strutturale per l'edificio in questione. In particolare è stata posta l'attenzione sulla struttura della peculiare copertura a padiglione, progettata utilizzando del legno lamellare

B cells in SLE. Different biological drugs for different pathogenic mechanisms

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease characterized by a complex multi-factorial pathogenesis and a great clinical polymorphism. SLE is considered to be a B cell disease in which autoantibodies are the major players. Recently, the central role of B cells has been confirmed and it has been shown that that the relative frequency of B cells subsets is altered in SLE patients. Conventional immunosuppressive therapies such as azathioprine, cyclophosphamide or methotrexate, reduce disease activity and improves the patient's general health conditions. These treatments have possible side effects; in fact they could compromise liver function, fertility and innate and adaptive immune responses. Moreover, for unknown reasons a small group of SLE patients is refractory to immunosuppressive therapy. In these cases finding an effective treatment becomes a challenge. The progress in therapeutic antibody technology has led to the production of a wide array of humanized monoclonal antibodies, targeting specific cell types or pathways, initiating a new era in the treatment of autoimmune disorders. In contrast to general immuno-suppression, the availability of drugs interfering with specific pathogenetic pathways gives the possibility to choose therapies tailored to each disease in each patient. © 2007 Elsevier B.V. All rights reserved

Microbiota and chronic inflammatory arthritis. an interwoven link

Background: Only recently, the scientific community gained insights on the importance of the intestinal resident flora for the host's health and disease. Gut microbiota in fact plays a crucial role in modulating innate and acquired immune responses and thus interferes with the fragile balance inflammation versus tolerance. Main body: Correlations between gut bacteria composition and the severity of inflammation have been studied in inflammatory bowel diseases. More recently similar alterations in the gut microbiota have been reported in patients with spondyloarthritis, whereas in rheumatoid arthritis an accumulating body of evidence evokes a pathogenic role for the altered oral microbiota in disease development and course. In the context of dysbiosis it is also important to remember that different environmental factors like stress, smoke and dietary components can induce strong bacterial changes and consequent exposure of the intestinal epithelium to a variety of different metabolites, many of which have an unknown function. In this perspective, and in complex disorders like autoimmune diseases, not only the genetic makeup, sex and immunologic context of the individual but also the structure of his microbial community should be taken into account. Conclusions: Here we provide a review of the role of the microbiota in the onset, severity and progression of chronic inflammatory arthritis as well as its impact on the therapeutic management of these patients. Furthermore we point-out the complex interwoven link between gut-joint-brain and immune system by reviewing the most recent data on the literature on the importance of environmental factors such as diet, smoke and stress

Structural and Functional Consequences Induced by Post-Translational Modifications in α-Defensins

HNP-1 is an antimicrobial peptide that undergoes proteolytic cleavage to become a mature peptide. This process represents the mechanism commonly used by the cells to obtain a fully active antimicrobial peptide. In addition, it has been recently described that HNP-1 is recognized as substrate by the arginine-specific ADP-ribosyltransferase-1. Arginine-specific mono-ADP-ribosylation is an enzyme-catalyzed post-translational modification in which NAD+ serves as donor of the ADP-ribose moiety, which is transferred to the guanidino group of arginines in target proteins. While the arginine carries one positive charge, the ADP-ribose is negatively charged at the phosphate moieties at physiological pH. Therefore, the attachment of one or more ADP-ribose units results in a marked change of cationicity. ADP-ribosylation of HNP-1 drastically reduces its cytotoxic and antibacterial activities. While the chemotactic activity of HNP-1 remains unaltered, its ability to induce interleukin-8 production is enhanced. The arginine 14 of HNP-1 modified by the ADP-ribose is in some cases processed into ornithine, perhaps representing a different modality in the regulation of HNP-1 activities

Higher risk of tuberculosis reactivation when anti-TNF is combined with immunosuppressive agents. A systematic review of randomized controlled trials

Objective. Treatment with tumour necrosis factor antagonists (anti-TNF) has been recognized as a risk factor for tuberculosis (TB) reactivation. Our aim was to evaluate risk of TB reactivation in rheumatologic and non-rheumatologic diseases treated with the same anti-TNF agents with and without concomitant therapies. Methods. We searched for randomized controlled trials (RCTs) evaluating infliximab, adalimumab, and certolizumab in both rheumatologic and non-rheumatologic diseases until 2012. Results were calculated as pooled rates and/or pooled odd ratios (OR). Results. Overall, 40 RCTs with a total of 14,683 patients (anti-TNF: 10,010; placebo: 4673) were included. TB reactivation was 0.26% (26/10,010) in the anti-TNF group and 0% (0/4673) in the control group, corresponding to an OR of 24.8 (95% CI 2.4-133). TB risk was higher when anti-TNF agents were combined with methotrexate or azathioprine as compared with either controls (24/4241 versus 0/4673; OR 54; 95% CI 5.3-88) or anti-TNF monotherapy (24/4241 versus 2/5769; OR 13.3; 95% CI 3.7-100). When anti-TNF was used as monotherapy, TB risk tended to be higher than placebo (2/5769 versus 0/4673; OR 4; 95% CI 0.2-15.7). Conclusions. TB risk with anti-TNF agents appeared to be increased when these agents were used in combination with methotrexate or azathioprine as compared with monotherapy regimen. TB risk seemed to be higher than placebo, even when monotherapy is prescribed

Interstitial Lung Disease in Rheumatoid Arthritis in the Era of Biologics

Interstitial lung disease (ILD) represents a severe manifestation in connective tissue diseases (CTD), with an overall incidence of 15%, and it is still a challenge for clinicians evaluation and management. ILD is the most common manifestation of lung involvement in Rheumatoid Arthritis (RA), observed in up to 80% of biopsies, 50% of chest Computed Tomography (CT) and only 5% of chest radiographs. Histopatological patterns of ILD in RA may present with different patterns, such as: usual interstitial pneumonia, non specific interstitial pneumonia, desquamative interstitial pneumonia, organizing pneumonia, and eosinophilic infiltration. The incidence of ILD in RA patients is not only related to the disease itself, many drugs may be in fact associated with the development of pulmonary damage. Some reports suggest a causative role for TNFα inhibitors in RA-ILD development/worsening, anyway, no definitive statement can be drawn thus data are incomplete and affected by several variables. A tight control (pulmonary function tests and/or HRCT) is mandatory in patients with preexisting ILD, but it should be also performed in those presenting risk factors for ILD and mild respiratory symptoms. Biologic therapy should be interrupted, and, after excluding triggering infections, corticosteroids should be administered

Editorial: Chronic autoimmune arthritis, infections and vaccines

The link between autoimmunity and infection continues to represent an intriguing immunologic conundrum for scientist and a frequent clinical challenge for patients and physicians. Patients with chronic autoimmune arthritis indeed have an increased risk of infections, mainly due to the dysregulation of their immune system and the use of immunosuppressive therapy. Infections in these patients are more frequent, have a more severe clinical course, eventually with prolonged viral persistence, compared to the general population and represent a frequent cause of death. Besides, infections can trigger autoimmune diseases via different immunologic mechanisms such as molecular mimicry, epitope spreading, by-stander activation and can also induce disease relapses. SARS-CoV-2 infection represents a dramatic example of this complex connection. It is known, indeed, that different autoimmune manifestations can complicate SARS-CoV-2 infection such as uncontrolled host-immune response leading to life-threatening condition known as cytokine release syndrome, or autoimmune hemolytic anemia, immune thrombocytopenic purpura, Guillain-Barre syndrome, and the detection of different autoantibodies. This Research Topic includes seventeen contributions, fifteen original articles and two review articles, providing several new insights into the efficacy and safety of SARS-CoV-2 vaccine in autoimmune patients, immunologic biomarkers for diagnosis and therapeutic outcome of autoimmune arthritis