1,721,304 research outputs found
Gut dysbiosis in Spondyloarthritis: Cause or effect?
No full textSpondyloarthritis (SpA) is a group of chronic, inflammatory rheumatic diseases mainly affecting the axial skeleton. Although the pathogenesis of the disease remains elusive, alterations of intestinal microbial composition have been demonstrated in patients with SpA and associated with intestinal and systemic immune alterations. Substantial data have been published in recent years in ethnically different patient populations, demonstrating in a consolidated way the presence of alterations in the composition of the microbial flora in patients with SpA. It is not currently possible to establish whether these alterations are intrinsically inherent in the disease, for example, the effect of particular genes that confer susceptibility to the disease itself, or are a consequence of a more systemic inflammatory process that also involves the intestine. However, data deriving from animal models and studies on relatives of patients with SpA strongly suggest that these alterations might precede the onset of the disease. In this review, we will try to critically analyze studies on dysbiosis in SpA and animal models of SpA, analyzing their functional consequences and the impact of biotechnological therapies on intestinal bacterial composition
Genetic and Environmental Determinants of T Helper 17 Pathogenicity in Spondyloarthropathies
No full textIn Spondyloarthropathies (SpA), a common group of immune-mediated diseases characterised by excessive inflammation of musculo-skeletal structures and extra-articular organs, T helper 17 (Th17) cells are widely considered the main drivers of the disease. Th17 are able to modulate their genes according to the immune environment: upon differentiation, they can adopt either housekeeping, anti-bacterial gene modules or inflammatory, pathogenic functions, and only the latter would mediate immune diseases, such as SpA. Experimental work aimed at characterising Th17 heterogeneity is largely performed on murine cells, for which the in vitro conditions conferring pathogenic potential have been identified and replicated. Interestingly, Th17 recognising different microorganisms are able to acquire specific cytokine signatures. An emerging area of research associates this heterogeneity to the preferential metabolic needs of the cell. In summary, the tissue environment could be determinant for the acquisition of pathogenetic features; this is particularly important at barrier sites, such as the intestine, considered one of the key target organs in SpA, and likely a site of immunological changes that initiate the disease. In this review, we briefly summarise genetic, environmental and metabolic factors that could explain how homeostatic, anti-microbial Th17 could turn into disease-causing cells in Spondyloarthritis
Erratum: IL-33 is overexpressed in the inflamed arteries of patients with giant cell arteritis (Annals of the Rheumatic Diseases (2013) 72 (258-64))
No full textBackground Autophagy has emerged as a critical homeostatic mechanism in T lymphocytes, influencing proliferation and differentiation. Autophagy in B cells has been less studied, but genetic deficiency causes impairment of early and late developmental stagesObjectives To explore the role of autophagy in the pathogenesis of human and murine lupus, a disease in which B cells are critical effectors of pathology.Methods Autophagy was assessed using multiple techniques in NZB/W and control mice, and in patients with systemic lupus erythematosus (SLE) compared to healthy controls. We evaluated the phenotype of the B cell compartment in Vav-Atg7(-/-) mice in vivo, and examined human and murine plasmablast formation following inhibition of autophagy.Results We found activation of autophagy in early developmental and transitional stages of B cell development in a lupus mouse model even before disease onset, and which progressively increased with age. In human disease, again autophagy was activated compared with healthy controls, principally in naive B cells. B cells isolated from Vav-Atg7(F/F) mice failed to effectively differentiate into plasma cells following stimulation in vitro. Similarly, human B cells stimulated in the presence of autophagy inhibition did not differentiate into plasmablasts.Conclusions Our data suggest activation of autophagy is a mechanism for survival of autoreactive B cells, and also demonstrate that it is required for plasmablast differentiation, processes that induce significant cellular stress. The implication of autophagy in two major pathogenic pathways in SLE suggests the potential to use inhibition of autophagy as a novel treatment target in this frequently severe autoimmune disease
Role of subclinical gut inflammation in the pathogenesis of spondyloarthritis
Full text linkSubclinical gut inflammation occurring in patients affected by spondyloarthritis (SpA) is correlated with the severity of spine inflammation. Several evidences indicate that dysbiosis occurs in SpA, and that may modulate intestinal permeability and intestinal immune responses. The presence of intestinal dysbiosis is accompanied in SpA patients with the presence of zonulin-dependent alterations of gut-epithelial and gut-vascular barriers. The leakage of epithelial and endothelial surface layers is followed by the translocation of bacterial products, such as lipopolysaccharide and intestinal fatty acid binding protein, in the systemic circulation. These bacterial products may downregulate the expression of CD14 on circulating monocytes leading to an "anergic" phenotype. In the gut, IL-23 may induce the expansion of innate immune cells such as mucosal-associated invariant T cells, γδ T cells, and innate lymphoid cells of group 3 that through the interaction with MAdCAM1 may recirculate form the gut to the sites of SpA active inflammation. On the basis of these findings, gut inflammation observed in SpA patient seems to be not only an epiphenomenon of the on going systemic inflammatory process but may also represent the base camp in which inflammatory cells are activated and from whom they shuttle
Gut inflammation in spondyloarthritis
No full textSpondyloarthritis (SpA) is a group of related diseases sharing common etiopathogenic mechanisms and clinical manifestations supported by a complex genetic predisposition. Gut inflammation is present in patients with SpA including patients showing clinically evident intestinal inflammation in the form of Crohn's disease or ulcerative colitis and patients who despite the absence of signs and symptoms of intestinal inflammation display a subclinical gut inflammation. Emerging evidence suggests that subclinical gut inflammation in patients with SpA, apparently driven by intestinal dysbiosis, is not the consequence of the systemic inflammatory process but rather an important pathophysiological event actively participating in the pathogenesis of the disease. The dysregulation of intestinal epithelial barrier possibly modulated by intestinal dysbiosis and especially in HLA-B27 + patients modulates local and systemic inflammation possibly representing the occult mechanism of the disease. This review aims to summarise current data on the role of the gastrointestinal involvement and intestinal microbiota in the pathogenesis of systemic rheumatic disease
Gut-derived CD8+ tissue-resident memory T cells are expanded in the peripheral blood and synovia of SpA patients
Full text linkPathogenesis of polymyalgia rheumatica
Full text linkPolymyalgia rheumatica (PMR) is a chronic, inflammatory disorder of unknown cause, almost exclusively occurring in people aged over 50 and often associated with giant cell arteritis. The evidence that PMR occurs almost exclusively in individuals aged over 50 may indicate that age-related immune alterations in genetically predisposed subjects contribute to development of the disease. Several infectious agents have been investigated as possible triggers of PMR even though the results are inconclusive. Activation of the innate and adaptive immune systems has been proved in PMR patients as demonstrated by the activation of dendritic cells and monocytes/macrophages and the altered balance between Th17 and Treg cells. Disturbed B cell distribution and function have been also demonstrated in PMR patients suggesting a pathogenesis more complex than previously imagined. In this review we will discuss the recent findings regarding the pathogenesis of PMR
Histopathology of the gut in rheumatic diseases
Full text linkThe gastrointestinal tract regulates the trafficking of macromolecules between the environment and the host through an epithelial barrier mechanism and is an important part of the immune system controlling the equilibrium between tolerance and immunity to non-self-antigens. Various evidence indicates that intestinal inflammation occurs in patients with rheumatic diseases. In many rheumatic diseases intestinal inflammation appears to be linked to dysbiosis and possibly represents the common denominator in the pathogenesis of different rheumatic diseases. The continuative interaction between dysbiosis and the intestinal immune system may lead to the aberrant activation of immune cells that can re-circulate from the gut to the sites of extraintestinal inflammation as observed in patients with ankylosing spondylitis. The exact contribution of genetic factors in the development of intestinal inflammation in rheumatic diseases needs to be clarified
Which patients with systemic lupus erythematosus in remission can withdraw low dose steroids? Results from a single inception cohort study
No full textBackground: A progressive tapering until withdrawal of glucocorticoids (GC) is considered one of the main goals of Systemic Lupus Erythematosus (SLE) management. However, which patient may be a candidate for safe GC withdrawal has not been determined yet. This study aimed to evaluate the rate of low-dose GC withdrawal in SLE patients in remission and to identify predictors of flares. Methods: Eligible patients were SLE patients in prolonged clinical remission defined by a cSLEDAI = 0 for at least 2 years and on a stable SLE treatment (including daily 5 mg prednisone). Flares were defined by SELENA-SLEDAI Flare Index. Predictors of flares after GC withdrawal were analyzed by Cox regression. Results: We selected 56 patients in whom a GC withdrawal was attempted. 98 patients were in the prednisone maintenance group. The proportion of patients experiencing a flare was not significantly lower in the maintenance group than in the withdrawal group (p = 0.81). However, among the withdrawal group, the rate of flares was significantly higher in serologically active clinically quiescent (SACQ) patients (p < 0,0001). At Cox regression analysis, duration of hydroxychloroquine (HCQ) therapy and ≥5 year remission at withdrawal were protective factors, while a SACQ disease and history of lupus nephritis increased the risk of disease flare. Conclusion: GC withdrawal is an achievable target in SLE and may be attempted in patients in complete remission.However, it might underline a caution in patients with SACQ disease who may be at greater risk forflare when GCare discontinued. HCQ therapy and durable remission can significantly reduce the risk
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