Pathogenesis of polymyalgia rheumatica

Polymyalgia 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.

HLA-C1 ligands are associated with increased susceptibility to systemic lupus erythematosus

Recently, the role of killer cell immunoglobulin-like receptor (KIR) in autoimmune diseases has received increasing attention. The present study was undertaken to determine the association of KIR genes and the human leukocytes antigen (HLA) ligands with Systemic Lupus Erythematosus (SLE) and accompanying oxidative stress. Presence or absence of 17 KIR and 5 HLA loci was performed using the polymerase chain reaction-sequence specific primer (PCR-SSP) method by case-control study. A total of 45 SLE patients, and 60 healthy controls, all of Sicilian descent, were enrolled. Plasma values of the anti-oxidant molecule Taurine were determined in all subjects by capillary electrophoresis UV detection. The carrier frequency of the KIR2DS2 gene was significantly increased in SLE patients compared to healthy controls (73.3 versus 45.0%; OR = 3.36; 95% CI = 1.46-7.74; p = .005) suggesting a role of KIR2DS2 gene in the susceptibility to disease. We also observed a strong positive association between the presence of HLA-C1 ligands group and the disease (82.2% in SLE patients versus 41.7% in controls; OR = 6.47, 95% CI = 2.58-16.26; p < .0001). Stepwise logistic regression analysis supported the effect of the HLA-C1 ligands in SLE patients (OR = 7.06, 95% CI = 0.07-2.19; p = .002), while the KIR genes were no longer significant. Interestingly, we found that SLE patients HLA-C1 positive showed significantly decreased plasma levels of antioxidant activity marker Taurine (69.38 ± 28.49 μmol/L) compared to SLE patients HLA-C1 negative (108.37 ± 86.09 μmol/L) (p = .03). In conclusion, HLA-C1 ligands group was significantly associated with an increased risk of SLE as well as an increased oxidative stress status overall in SLE patients.

The Janus Face of NKT Cell Function in Autoimmunity and Infectious Diseases

Natural killer T cells (NKT) are a subset of T lymphocytes bridging innate and adaptive immunity. These cells recognize self and microbial glycolipids bound to non-polymorphic and highly conserved CD1d molecules. Three NKT cell subsets, type I, II, and NKT-like expressing different antigen receptors (TCR) were described and TCR activation promotes intracellular events leading to specific functional activities. NKT can exhibit different functions depending on the secretion of soluble molecules and the interaction with other cell types. NKT cells act as regulatory cells in the defense against infections but, on the other hand, their effector functions can be involved in the pathogenesis of several inflammatory disorders due to their exposure to different microbial or self-antigens, respectively. A deep understanding of the biology and functions of type I, II, and NKT-like cells as well as their interplay with cell types acting in innate (neuthrophils, innate lymphoid cells, machrophages, and dendritic cells) and adaptive immunity (CD4⁺,CD8⁺, and double negative T cells) should be important to design potential immunotherapies for infectious and autoimmune diseases.

Sclerostin and Antisclerostin Antibody Serum Levels Predict the Presence of Axial Spondyloarthritis in Patients with Inflammatory Bowel Disease

OBJECTIVE

The early diagnosis of inflammatory bowel disease (IBD)-associated spondyloarthritis (SpA/IBD) in patients affected by IBD represents a major topic in clinical practice; in particular, to date there are no available serum biomarkers revealing the presence of joint inflammation in these patients. Sclerostin (SOST), an antagonist of the Wnt/β-catenin pathway, and antisclerostin-immunoglobulin G (anti-SOST-IgG) have been recently studied in patients with ankylosing spondylitis (AS) as a putative marker of disease activity.

METHODS

SOST and anti-SOST-IgG serum levels were assayed in 125 patients with IBD, 85 with axial or peripheral SpA, and in control groups (patients with AS and rheumatoid arthritis, and healthy individuals). The diagnostic performance in discriminating the presence of SpA/IBD was assessed for both candidate biomarkers.

RESULTS

Patients affected by SpA/IBD with axial involvement displayed significantly lower levels of SOST and higher levels of anti-SOST-IgG compared to patients with only peripheral arthritis, IBD, and controls. Moreover, SOST and anti-SOST-IgG serum levels were inversely correlated and were associated with the duration of articular symptoms. Both biomarkers showed good accuracy in predicting the presence of axial SpA in patients with IBD.

CONCLUSION

We demonstrated that in patients with IBD, SOST and anti-SOST-IgG might represent novel biomarkers to assess the presence of axial joint involvement. Moreover, the development of anti-SOST-IgG and the subsequent decrease of SOST serum levels could play a role in the pathogenesis of SpA/IBD.

H-ferritin and proinflammatory cytokines are increased in the bone marrow of patients affected by macrophage activation syndrome

Macrophage activation syndrome (MAS) is hyperinflammatory life-threatening syndrome, associated typically with high levels of serum ferritin. This is an iron storage protein including heavy (H) and light (L) subunits, categorized on their molecular weight. The H-/L subunits ratio may be different in tissues, depending on the specific tissue and pathophysiological status. In this study, we analysed the bone marrow (BM) biopsies of adult MAS patients to assess the presence of: (i) H-ferritin and L-ferritin; (ii) CD68⁺ /H-ferritin⁺ and CD68⁺ /L-ferritin⁺ ; and (iii) interleukin (IL)-1β, tumour necrosis factor (TNF) and interferon (IFN)-γ. We also explored possible correlations of these results with clinical data. H-ferritin, IL-1β, TNF and IFN-γ were increased significantly in MAS. Furthermore, an increased number of CD68⁺ /H-ferritin⁺ cells and an infiltrate of cells co-expressing H-ferritin and IL-12, suggesting an infiltrate of M1 macrophages, were observed. H-ferritin levels and CD68⁺ /H-ferritin⁺ cells were correlated with haematological involvement of the disease, serum ferritin and C-reactive protein. L-ferritin and CD68⁺ /L-ferritin⁺ cells did not correlate with these parameters. In conclusion, during MAS, H-ferritin, CD68⁺ /H-ferritin⁺ cells and proinflammatory cytokines were increased significantly in the BM inflammatory infiltrate, pointing out a possible vicious pathogenic loop. To date, H-ferritin and CD68⁺ /H-ferritin⁺ were associated significantly with haematological involvement of the disease, suggesting biomarkers assessing severity of clinical picture.

Advances in immunopathogenesis of macrophage activation syndrome during rheumatic inflammatory diseases: toward new therapeutic targets?

INTRODUCTION

Macrophage activation syndrome (MAS) is a severe, hyperinflammatory life-threatening syndrome, generally complicating different rheumatic diseases. Despite the severity of the disease, little is known about the pathogenic mechanisms and, thus, possible targeted therapies in the management of these patients. Areas covered: In this review, we aimed to update the current pathogenic knowledge of MAS, during rheumatic diseases, focusing mainly on immunologic abnormalities and on new possible therapeutic strategies. Expert commentary: The difficult pathogenic scenario of MAS, in which genetic defects, predisposing diseases, and triggers are mixed together with the high mortality rate, make it difficult to manage these patients. Although most efforts have been focused on investigating the disease in children, in recent years, several studies are trying to elucidate the possible pathogenic mechanism in adult MAS patients. In this context, genetic and immunological studies might lead to advances in the knowledge of pathogenic mechanisms and possible new therapeutic targets. In the future, the results of ongoing clinical trials are awaited in order to improve the management and, thus, the survival of these patients.

Interleukin-9 over-expression and T helper 9 polarization in systemic sclerosis patients

T helper 9 (Th9) cells and interleukin (IL)-9 are involved in the pathogenesis of several autoimmune diseases. The exact role of IL-9 and Th9 cells in patients with systemic sclerosis (SSc) have not yet been studied adequately. IL-9, IL-9R, transcription factor PU.1 (PU.1), IL-4, thymic stromal lymphopoietin (TSLP) and transforming growth factor (TGF)-β expression were assessed in skin and kidney biopsies of SSc patients and healthy controls (HC) by immunohistochemistry (IHC). The cellular source of IL-9 was also analysed by confocal microscopy analysis. Peripheral IL-9-producing cells were also studied by flow cytometry. The functional relevance of IL-9 increased expression in SSc was also investigated. Our results demonstrated a strong expression of IL-9, IL-9R, IL-4, TSLP and TGF-β in skin tissues of patients with both limited and diffuse SSc. IL-9 expression was observed mainly in the context of skin infiltrating mononuclear cells and keratinizing squamous epithelium. IL-9 over-expression was also observed in renal biopsies of patients with SSc. IL-9 producing cells in the skin were identified as Th9 cells. Similarly, Th9 cells were expanded and were the major source of IL-9 among SSc peripheral blood mononuclear cells (PBMC), their percentage being correlated directly with the modified Rodnan skin score. Infiltrating mononuclear cells, mast cells and neutrophils expressed IL-9R. In in-vitro studies stimulation with rIL-9 significantly induced NET (neutrophil extracellular traps) release by dying cells (NETosis) in neutrophils, expansion of mast cells and increase of anti-systemic scleroderma 70 (Scl70) production by B cells. Our findings suggest that Th9 cells and IL-9 could be implicated in the pathogenesis of SSc.

Prevalence of type 2 diabetes and impaired fasting glucose in patients affected by rheumatoid arthritis: Results from a cross-sectional study

Although the better management of rheumatoid arthritis (RA) has significantly improved the long-term outcome of affected patients, a significant proportion of these may develop associated comorbidities including cardiometabolic complications. However, it must be pointed out that a comprehensive cardiometabolic evaluation is still poorly integrated into the management of RA patients, due to a limited awareness of the problem, a lack of appropriate clinical studies, and optimal strategies for cardiovascular (CV) risk reduction in RA. In addition, although several studies investigated the possible association between traditional CV risk factors and RA, conflicting results are still available.On this basis, we planned this cross-sectional study, aimed at investigating the prevalence of type 2 diabetes (T2D) and impaired fasting glucose (IFG) in RA patients compared with age- and gender- matched control individuals. Furthermore, we analyzed the role of both traditional and RA-related CV risk factors in predicting T2D and IFG.We observed an increased prevalence of T2D in RA patients when compared with age- and gender-matched controls. Regression analyses demonstrated that the presence of high blood pressure (HBP), a longer disease duration, and exposure to corticosteroids (CCS) were significantly associated with an increased likelihood of being classified as T2D. In addition, we observed an increased prevalence of IFG in RA patients when compared with age- and gender-matched controls. Regression analyses demonstrated that a higher body mass index (BMI), the presence of metabolic syndrome (MetS), higher levels of total cholesterol, the presence of radiographic damage, and higher serum levels of C-reactive protein (CRP) were significantly associated with an increased likelihood of presenting IFG.In this cross-sectional study, we observed an increased prevalence of T2D and IFG in an Italian cohort of RA patients when compared with age- and gender-matched control individuals. Interestingly, both RA-specific features, such as disease duration, CCS exposure, and radiographic damage, and traditional CV risk factors, such as HBP and MetS, were significantly associated with glucose metabolism abnormalities.

CD4 T lymphocyte autophagy is upregulated in the salivary glands of primary Sjögren's syndrome patients and correlates with focus score and disease activity

BACKGROUND

Primary Sjögren's syndrome (pSS) is a common chronic autoimmune disease characterized by lymphocytic infiltration of exocrine glands and peripheral lymphocyte perturbation. In the current study, we aimed to investigate the possible pathogenic implication of autophagy in T lymphocytes in patients with pSS.

METHODS

Thirty consecutive pSS patients were recruited together with 20 patients affected by sicca syndrome and/or chronic sialoadenitis and 30 healthy controls. Disease activity and damage were evaluated according to SS disease activity index, EULAR SS disease activity index, and SS disease damage index. T lymphocytes were analyzed for the expression of autophagy-specific markers by biochemical, molecular, and histological assays in peripheral blood and labial gland biopsies. Serum interleukin (IL)-23 and IL-21 levels were quantified by enzyme-linked immunosorbent assay.

RESULTS

Our study provides evidence for the first time that autophagy is upregulated in CD4⁺ T lymphocyte salivary glands from pSS patients. Furthermore, a statistically significant correlation was detected between lymphocyte autophagy levels, disease activity, and damage indexes. We also found a positive correlation between autophagy enhancement and the increased salivary gland expression of IL-21 and IL-23, providing a further link between innate and adaptive immune responses in pSS.

CONCLUSIONS

These findings suggest that CD4⁺ T lymphocyte autophagy could play a key role in pSS pathogenesis. Additionally, our data highlight the potential exploitation of T cell autophagy as a biomarker of disease activity and provide new ground to verify the therapeutic implications of autophagy as an innovative drug target in pSS.

Interleukin-9 Overexpression and Th9 Polarization Characterize the Inflamed Gut, the Synovial Tissue, and the Peripheral Blood of Patients With Psoriatic Arthritis

OBJECTIVE

To investigate the expression and tissue distribution of Th9-related cytokines in patients with psoriatic arthritis (PsA).

METHODS

Quantitative gene expression analysis of Th1, Th17, and Th9 cytokines was performed in intestinal biopsy samples obtained from patients with PsA, HLA-B27-positive patients with ankylosing spondylitis (AS), patients with Crohn's disease (CD), and healthy controls. Expression and tissue distribution of interleukin-23 (IL-23), IL-17, IL-22, IL-9, and IL-9 receptor (IL-9R) were evaluated by immunohistochemistry and confocal microscopy. Flow cytometry was used to study the frequency of Th9 cells among peripheral blood, lamina propria, and synovial fluid mononuclear cells. The functional relevance of IL-9R expression on epithelial cells was assessed in functional in vitro studies. Th9 cells in synovial tissue from patients with PsA were also studied.

RESULTS

Subclinical gut inflammation in PsA patients was characterized by a clear Th17 and Th22, but not Th1, polarized immune response. Unlike AS and CD, a strong and significant up-regulation of IL-9 was observed in PsA gut, especially among infiltrating mononuclear cells, high endothelial venules, and Paneth cells. IL-9-positive mononuclear cells were demonstrated to be in large part Th9 cells. IL-9 overexpression was accompanied by significant Paneth cell hyperplasia. Paneth cells strongly overexpressed IL-9R, and stimulation of epithelial cells, isolated from PsA patients, with IL-9 resulted in overexpression of α-defensin 5 and IL-23p19. Peripheral and synovial expansion of α4β7+ Th9 cells was also observed in patients with PsA. Increased expression of IL-9 and IL-9R was also found in synovial tissue.

CONCLUSION

Strong IL-9/Th9 polarization seems to be the predominant immunologic signature in patients in PsA.

Interleukin-9 and T helper type 9 cells in rheumatic diseases

Interleukin (IL)-9 is a 28-30 kDa monomeric glycosylated polypeptide belonging to the IL-7/IL-9 family of proteins that bind to a composite receptor consisting of the private receptor IL-9R and the IL-2 receptor, gamma (IL-2RG), a common gamma subunit shared by the receptors of many different cytokines. The IL-9R is expressed widely and IL-9 impacts a number of effector cells, such as effector T cells, B cells, innate lymphoid cells, mast cells, polymorphonuclear cells, epithelial cells and smooth muscle cells, playing an important role in regulating inflammatory immunity. The critical role of IL-9 in promoting cellular and humoral immune responses makes it an important focus of potential therapeutic interventions. Recently, a defined subset of T helper type cells, Th9 cells, has been identified by the potent production of IL-9. The involvement of the Th9 cell subset has been described in many types of inflammatory diseases, namely atopic diseases, helminth infections, experimental autoimmune encephalomyelitis and ulcerative colitis. In this review, we summarize the IL-9 biological activities, highlighting roles for IL-9 and Th9 cells in rheumatoid and psoriatic arthritis, systemic vasculitis, systemic lupus erythematosus and systemic sclerosis.

Dysbiosis and zonulin upregulation alter gut epithelial and vascular barriers in patients with ankylosing spondylitis

BACKGROUND

Dysbiosis has been recently demonstrated in patients with ankylosing spondylitis (AS) but its implications in the modulation of intestinal immune responses have never been studied. The aim of this study was to investigate the role of ileal bacteria in modulating local and systemic immune responses in AS.

METHODS

Ileal biopsies were obtained from 50 HLA-B27⁺ patients with AS and 20 normal subjects. Silver stain was used to visualise bacteria. Ileal expression of tight and adherens junction proteins was investigated by TaqMan real-time (RT)-PCR and immunohistochemistry. Serum levels of lipopolysaccharide (LPS), LPS-binding protein (LPS-BP), intestinal fatty acid-BP (iFABP) and zonulin were assayed by ELISA. Monocyte immunological functions were studied in in vitro experiments. In addition the effects of antibiotics on tight junctions in human leukocyte antigen (HLA)-B27 transgenic (TG) rats were assessed.

RESULTS

Adherent and invasive bacteria were observed in the gut of patients with AS with the bacterial scores significantly correlated with gut inflammation. Impairment of the gut vascular barrier (GVB) was also present in AS, accompanied by significant upregulation of zonulin, and associated with high serum levels of LPS, LPS-BP, iFABP and zonulin. In in vitro studies zonulin altered endothelial tight junctions while its epithelial release was modulated by isolated AS ileal bacteria. AS circulating monocytes displayed an anergic phenotype partially restored by ex vivo stimulation with LPS+sCD14 and their stimulation with recombinant zonulin induced a clear M2 phenotype. Antibiotics restored tight junction function in HLA-B27 TG rats.

CONCLUSIONS

Bacterial ileitis, increased zonulin expression and damaged intestinal mucosal barrier and GVB, characterises the gut of patients with AS and are associated with increased blood levels of zonulin, and bacterial products. Bacterial products and zonulin influence monocyte behaviour.

Adult-onset Still's disease: evaluation of prognostic tools and validation of the systemic score by analysis of 100 cases from three centers

BACKGROUND

Adult-onset Still's disease (AOSD) is rare inflammatory disease of unknown etiology that usually affects young adults. The more common clinical manifestations are spiking fevers, arthritis, evanescent rash, elevated liver enzymes, lymphadenopathy, hepatosplenomegaly, and serositis. The multi-visceral involvement of the disease and the different complications, such as macrophage activation syndrome, may strongly decrease the life expectancy of AOSD patients.

METHODS

This study aimed to identify the positive and negative features correlated with the outcome of patients. A retrospective analysis of AOSD patients prospectively admitted to three rheumatologic centers was performed to identify the clinical features present at the time of diagnosis and to predict the possible outcome. Furthermore, we investigated the as yet to be validated prognostic value of the systemic score previously proposed.

RESULTS

One hundred consecutive AOSD patients were enrolled. The mean systemic score showed that the majority of patients had a multi-organ involvement. Sixteen patients showed different complications, mainly the macrophage activation syndrome. A strong increase of inflammatory markers was observed. All patients received steroids at different dosages, 55 patients in association with immunosuppressive drugs and 32 in association with biologic agents. Sixteen patients died during the follow-up. Regression analysis showed that the higher values of the systemic score and the presence of AOSD-related complications, assessed at the time of diagnosis, were significantly correlated with patient mortality. A prognostic impact of the systemic score of ≥ 7.0 was reported.

CONCLUSIONS

Our study showed that a higher systemic score and the presence of AOSD-related complications at the time of diagnosis were significantly associated with mortality. Of note, a cut-off at 7.0 of the systemic score showed a strong prognostic impact in identifying patients at risk of AOSD-related death.

Interleukin (IL)-9/IL-9R axis drives γδ T cells activation in psoriatic arthritis patients

Cytokines such as tumour necrosis factor (TNF)-α, interleukin (IL)-12, interferon (IFN)-γ, IL-23 and, more recently, IL-9, have been implicated in the initiation/maintenance of inflammation in psoriasis and psoriatic arthritis (PsA). In the present study we aimed to characterize the role of γδ T cells in peripheral blood and synovial fluid of PsA patients and to investigate their response to in-vitro stimulation with antigen or cytokines (IL-9 and IL-23). γδ T cells isolated from peripheral blood mononuclear cells and synovial fluid were analysed by flow cytometry to evaluate the phenotype and cytokine production. IL-23R and IL-9R gene expression were also evaluated by reverse transcription-polymerase chain reaction (RT-PCR). Peripheral blood mononuclear cells (PBMC), sorted γδ T cells and γδ cell lines were also stimulated in vitro with isopentenyl pyrophosphate (IPP), recombinant IL-9 or recombinant IL-23. Our results show an expansion of γδ T cells with a predominant effector memory phenotype in peripheral blood and synovium of untreated PsA patients, which reverses significantly after treatment with anti-TNF-α or anti-IL-12/IL-23R monoclonal antibodies (mAbs). Moreover, in PsA patients γδ T cells activation is driven prevalently by IL-9/IL-9R interaction, and not only by IL-23/IL-23R. Together these findings indicate γδ T cells and IL-9 as new players in the pathogenesis of PsA.

Prognostic factors of macrophage activation syndrome, at the time of diagnosis, in adult patients affected by autoimmune disease: Analysis of 41 cases collected in 2 rheumatologic centers

Macrophage activation syndrome (MAS) is a rare, life-threatening disease in which early diagnosis and aggressive therapeutic strategy may improve the outcome. Due to its rarity, epidemiologic data are still lacking. Hyperferritinemia is frequently associated with MAS and might modulate the cytokine storm, which is involved in the development of multiple organ failure. In this paper, we investigated clinical data, treatments, and outcome of a homogeneous cohort of 41 adult MAS patients, complicating autoimmune rheumatic diseases. MAS-related death occurred in 17 patients (42.5%) during the follow-up, and older age and increased serum ferritin levels, at the time of diagnosis, were significantly associated with mortality. In conclusion, adult MAS is associated with high mortality rate. Some clinical features at diagnosis may be predictive of MAS-associated death.

H-ferritin and CD68(+) /H-ferritin(+) monocytes/macrophages are increased in the skin of adult-onset Still's disease patients and correlate with the multi-visceral involvement of the disease

Adult-onset Still's disease (AOSD) patients may show an evanescent salmon-pink erythema appearing during febrile attacks and reducing without fever. Some patients may experience this eruption for many weeks. During AOSD, exceptionally high serum levels of ferritin may be observed; it is an iron storage protein composed of 24 subunits, heavy (H) subunits and light (L) subunits. The ferritin enriched in L subunits (L-ferritin) and the ferritin enriched in H subunits (H-ferritin) may be observed in different tissues. In this work, we aimed to investigate the skin expression of both H-and L-ferritin and the number of macrophages expressing these molecules from AOSD patients with persistent cutaneous lesions. We observed an increased expression of H-ferritin in the skin, associated with an infiltrate in the biopsies obtained from persistent cutaneous lesions of AOSD patients. Furthermore, a positive correlation between H-ferritin skin levels as well as the number of CD68(+) /H-ferritin(+) cells and the multi-visceral involvement of the disease was observed. Our data showed an increased expression of H-ferritin in the skin of AOSD patients, associated with a strong infiltrate of CD68(+) /H-ferritin(+) cells. Furthermore, a correlation between the levels of H-ferritin as well as of the number of CD68(+) /H-ferritin(+) cells and the multi-visceral involvement of the disease was observed.

Predominance of Type 1 Innate Lymphoid Cells in the Rectal Mucosa of Patients With Non-Celiac Wheat Sensitivity: Reversal After a Wheat-Free Diet

OBJECTIVES:

Non-celiac wheat sensitivity (NCWS) is defined as a reaction to ingested wheat after exclusion of celiac disease and wheat allergy. As its pathogenesis is incompletely understood, we evaluated the inflammatory response in the rectal mucosa of patients with well-defined NCWS.

METHODS:

The prospective study included 22 patients with irritable bowel syndrome (IBS)-like clinical presentation, diagnosed with NCWS by double-blind placebo-controlled challenge. Eight IBS patients not improving on wheat-free diet were used as controls. Two weeks after oral challenge was performed with 80 grams of wheat daily, cells were isolated from rectal biopsies and thoroughly characterized by fluorescence-activated cell sorting analysis for intracellular cytokines and surface markers.

RESULTS:

Rectal biopsies from wheat-challenged NCWS patients showed that a significant mucosal CD45⁺ infiltrate consisted of CD3⁺ and CD3⁻ lymphocytes, with the latter spontaneously producing more interferon (IFN)-γ than IBS controls. About 30% of IFN-γ-producing CD45⁺ cells were T-bet⁺, CD56⁻, NKP44⁻, and CD117⁻, defining them as a type-1 innate lymphoid cells (ILC1). IFN-γ-producing ILC1 cells significantly decreased in 10 patients analyzed 2 weeks after they resumed a wheat-free diet.

CONCLUSIONS:

These data indicate that, in patients with active NCWS, IFN-γ-producing ILC1 cells infiltrate rectal mucosa and support a role for this innate lymphoid cell population in the pathogenesis of NCWS.

Perivascular Cells in Diffuse Cutaneous Systemic Sclerosis Overexpress Activated ADAM12 and Are Involved in Myofibroblast Transdifferentiation and Development of Fibrosis

Objective.

Microvascular damage is pivotal in the pathogenesis of systemic sclerosis (SSc), preceding fibrosis, and whose trigger is not still fully understood. Perivascular progenitor cells, with profibrotic activity and function, are identified by the expression of the isoform 12 of ADAM (ADAM12) and this molecule may be upregulated by transforming growth factor-β (TGF-β). The goal of this work was to evaluate whether pericytes in the skin of patients with diffuse cutaneous SSc (dcSSc) expressed ADAM12, suggesting their potential contribution to the fibrotic process, and whether TGF-β might modulate this molecule.

Methods.

After ethical approval, mesenchymal stem cells (MSC) and fibroblasts (FB) were isolated from bone marrow and skin samples collected from 20 patients with dcSSc. ADAM12 expression was investigated in the skin and in isolated MSC and FB treated with TGF-β by immunofluorescence, quantitative real-time PCR, and western blot. Further, we silenced ADAM12 expression in both dcSSc-MSC and -FB to confirm the TGF-β modulation.

Results.

Pericytes and FB of dcSSc skin showed an increased expression of ADAM12 when compared with healthy control skin. TGF-β in vitro treatment induced a significant increase of ADAM12 in both SSc-MSC and -FB, with the higher levels observed in dcSSc cells. After ADAM12 silencing, the TGF-β ability to upregulate α-smooth muscle actin in both SSc-MSC and SSc-FB was inhibited.

Conclusion.

Our results suggest that in SSc, pericytes that transdifferentiate toward activated FB are present in the vascular tree, and TGF-β, while increasing ADAM12 expression, may modulate this transdifferentiation.

Ectopic expression of CXCL13, BAFF, APRIL and LT-β is associated with artery tertiary lymphoid organs in giant cell arteritis

OBJECTIVES

To investigate whether artery tertiary lymphoid organs (ATLOs) are present in giant cell arteritis (GCA) and that their formation is associated with the ectopic expression of constitutive lymphoid tissue-homing chemokines.

METHODS

Reverse transcriptase PCR, immunohistochemical and immunofluorescence analysis were used to determine the presence of ectopic ATLOs in GCA and the expression of chemokines/chemokine receptors and cytokines involved in lymphoneogenesis in the temporal artery samples obtained from 50 patients with GCA and 30 controls. The presence of lymphatic conduits, of follicular dendritic cells (FDCs) precursors and lymphoid tissue inducer cells was also investigated. Finally, expression of CXCL13, B cell activating factor (BAFF), a proliferation-inducing ligand (APRIL) and CCL21 by isolated myofibroblasts was evaluated before and after stimulation with Toll-like receptors (TLRs) agonists and cytokines.

RESULTS

ATLOs were observed in the media layer of 60% of patients with GCA in close proximity to high endothelial venules and independently by the age of patients and the presence of atherosclerosis. ATLO formation was also accompanied by the expression of CXCL13, BAFF, a proliferation-inducing ligand (APRIL), lymphotoxin (LT)-β, interleukin (IL)-17 and IL-7, the presence of FDC precursors and of lymphoid conduits. Stimulation of myofibroblasts with TLR agonists and cytokines resulted in the upregulation of BAFF and CXCL13.

CONCLUSIONS

ATLOs occur in the inflamed arteries of patients with GCA possibly representing the immune sites where immune responses towards unknown arterial wall-derived antigens may be organised.

IL-1β at the crossroad between rheumatoid arthritis and type 2 diabetes: may we kill two birds with one stone?

Although in the past the prevention of joint destruction in rheumatoid arthritis (RA) was strongly emphasized, now a great interest is focused on associated comorbidities in these patients. Multiple data suggest that a large percentage of RA patients are affected by Type 2 Diabetes (T2D), whose incidence has reached epidemic levels in recent years, thus increasing the health care costs. A better knowledge about the pathogenesis of these diseases as well as the mechanisms of action of drugs may allow both policy designers and physicians to choose the most effective treatments, thus lowering the costs. This review will focus on the role of Interleukin (IL)-1β in the pathogenesis of both the diseases, the efficacy of IL-1 blocking molecules in controlling these diseases, and will provide information suggesting that targeting IL-1β, in patients affected by both RA and T2D, may be a promising therapeutic choice.

Non-conventional forms of HLA-B27 are expressed in spondyloarthritis joints and gut tissue

Objectives

Human leukocyte antigen (HLA)-B27 (B27) is the strongest genetic factor associated with development of Ankylosing Spondylitis and other spondyloarthropathies (SpA), yet the role it plays in disease pathogenesis remains unclear. We investigated the expression of potentially pathogenic non-conventional heavy chain forms (NC) of B27 in synovial and intestinal tissues obtained from SpA patients. We also determined the presence of NC-B27 in joints, lymphoid and gastrointestinal tissue from B27 transgenic (TG¹) rats with M.tuberculosis-induced SpA.

Methods

Expression of NC-B27 in human SpA joints and gut and in (21-3 × 283-2)F₁ HLA-B27/Huβ2m rat tissue was determined by immunohistochemistry, flow cytometry and confocal microscopy analysis using HC10 and HD6 antibodies.

Results

Both HC10- and HD6-reactive HLA molecules were present in synovial tissue from SpA patients. Both NC-B27 and KIR3DL2, a ligand for NC-B27, were expressed in inflamed terminal ileal tissues in patients with early SpA. Infiltrating cells in inflamed joint tissues isolated from B27 TG¹ rats expressed high levels of NC-B27. NC-B27 were also expressed in joint-resident cells from ankle and tail joints of B27 TG¹ rats prior to clinical arthritis. The expression of NC-B27 on B27 TG¹ rat CD11b/c⁺, CD8α⁺, cells from spleens and LNs increased with animal age and disease progression.

Conclusions

Non-conventional HLA class 1 molecules are expressed on resident and infiltrating cells in both synovial and GI tissues in human SpA. NC-B27 expression in joints and lymphoid tissues from B27 TG¹ rats prior to the onset of arthritis is consistent with the hypothesis that they play a pathogenic role in SpA.

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HLA-B27 predisposes to Ankylosing Spondylitis and related Spondyloarthritis (SpA).

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Non-conventional HLA-B27 free heavy chains (NC-B27) bind innate immune receptors.

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NC HLA class I molecules are expressed in joint and gut tissues in human and rat SpA.

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B27 transgenic rats express NC-B27 prior to arthritis onset.

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These data support a pathogenic role for non-conventional B27 in SpA.

Invariant NKT cells are expanded in peripheral blood but are undetectable in salivary glands of patients with primary Sjögren's syndrome

OBJECTIVES

Invariant NKT (iNKT) cells play a role in regulating the function of autoreactive B cells before their entry into germinal centres. Absence and/or reduction of iNKT cells have been demonstrated in patients with systemic lupus erythematosus (SLE) together with an increase of autoreactive B cell activity. Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease in which lymphocyte infiltration and organisation in lymphoid structures of inflamed salivary glands occurs. The aim of the study was to investigate the percentage and function of iNKT in the salivary glands and peripheral blood of patients with pSS.

METHODS

Minor salivary gland biopsies were obtained from patients with pSS and with non-specific chronic sialoadenitis (nSS). Flow cytometry analysis of CD1d/α-GalactosylCeramide (α-GalCer) tetramer positive cells, producing IFN-γ and IL-17, and quantitative gene expression analysis by TaqMan real-time PCR for Vα24 were performed on salivary glands biopsies and peripheral blood samples obtained from patients and controls. Flow cytometry and immunofluorescence analysis for autoreactive B lymphocytes and ELISA for anti-SSA antibodies (Ab) detection were also performed.

RESULTS

An increase of iNKT was detected ex vivo in peripheral blood of pSS patients; after α-GalCer stimulation this subset produce IL-17 and IFN-iNKT were undetectable in the salivary glands of pSS patients and anti-SSA specific B cells were found in target tissue. Invariant NKT cells were able to inhibit autoantibody production by B cells obtained from salivary glands of pSS.

CONCLUSIONS

Impaired iNKT migration to inflamed sites might induce the activation of autoreactive B cells specific for SSA-antigen in salivary glands of pSS patients.

The CD68(+)/H-ferritin(+) cells colonize the lymph nodes of the patients with adult onset Still's disease and are associated with increased extracellular level of H-ferritin in the same tissue: correlation with disease severity and implication for pathogenesis

In this work, we aimed to evaluate the levels of ferritin enriched in H subunits (H-ferritin) and ferritin enriched in L subunits (L-ferritin) and the cells expressing these two molecules in the lymph node (LN) biopsies obtained from adult-onset Still's disease (AOSD) patients, and the possible correlation among these data and the severity of the disease. Ten patients with AOSD underwent LN biopsy. All the samples were stained by immunofluorescence. A statistical analysis was performed to estimate the possible correlation among both H-ferritin and L-ferritin tissue expression and the clinical picture of the disease. Furthermore, the same analysis was performed to evaluate the possible correlation among the number of CD68(+)/H-ferritin(+) or CD68(+)/L-ferritin(+) cells and the clinical picture. Immunofluorescence analysis demonstrated an increased tissue H-ferritin expression in the LNs of AOSD patients. This increased expression correlated with the severity of the disease. An increased number of CD68 macrophages expressing H-ferritin was observed in the LN samples of our patients. Furthermore, we observed that the number of CD68(+)/H-ferritin(+) cells correlated significantly with the severity of the clinical picture. Our data showed an imbalance between the levels of H- and L-ferritin in LNs of AOSD patients and the evidence of an increased number of CD68(+)/H-ferritin(+) cells in the same organs. Furthermore, a correlation among both the tissue H-ferritin levels and the CD68(+)/H-ferritin(+) cells and the clinical picture was observed.

Impact of immunosuppressive drugs on the therapeutic efficacy of ex vivo expanded human regulatory T cells

Immunosuppressive drugs in clinical transplantation are necessary to inhibit the immune response to donor antigens. Although they are effective in controlling acute rejection, they do not prevent long-term transplant loss from chronic rejection. In addition, immunosuppressive drugs have adverse side effects, including increased rate of infections and malignancies. Adoptive cell therapy with human Tregs represents a promising strategy for the induction of transplantation tolerance. Phase I/II clinical trials in transplanted patients are already underway, involving the infusion of Tregs alongside concurrent immunosuppressive drugs. However, it remains to be determined whether the presence of immunosuppressive drugs negatively impacts Treg function and stability. We tested in vitro and in vivo the effects of tacrolimus, mycophenolate and methylprednisolone (major ISDs used in transplantation) on ex vivo expanded, rapamycin-treated human Tregs. The in vitro results showed that these drugs had no effect on phenotype, function and stability of Tregs, although tacrolimus affected the expression of chemokine receptors and IL-10 production. However, viability and proliferative capacity were reduced in a dose-dependent manner by all the three drugs. The in vivo experiments using a humanized mouse model confirmed the in vitro results. However, treatment of mice with only rapamycin maintained the viability, function and proliferative ability of adoptively transferred Tregs. Taken together, our results suggest that the key functions of ex vivo expanded Tregs are not affected by a concurrent immunosuppressive therapy. However, the choice of the drug combination and their timing and dosing should be considered as an essential component to induce and maintain tolerance by Treg.

Type 3 innate lymphoid cells producing IL-17 and IL-22 are expanded in the gut, in the peripheral blood, synovial fluid and bone marrow of patients with ankylosing spondylitis

BACKGROUND

The aim of the study was to better characterise the immunological origin and the behaviour of interleukin (IL)-23-responsive innate lymphoid cells (ILCs) in the gut, synovial fluid (SF) and bone marrow (BM) of patients with ankylosing spondylitis (AS).

METHODS

ILC1, ILC2 and ILC3 cells were determined and characterised by confocal microscopy and flow cytometry in ileal and BM biopsies, in peripheral blood (PB) and SF mononuclear cells obtained from patients with AS and controls. Mucosal vascular addressin cell adhesion molecule 1 (MADCAM-1), IL-7, IL-15 and aggregates of lymphoid tissue inducer cells (LTi) were evaluated by immunohistochemistry. The in vitro ability of epithelial cells in driving the differentiation of ILC3 and the effect of tumour necrosis factor inhibitors (TNFi) on the frequency of ILC3 and the expression of MADCAM1 were also assessed.

RESULTS

ILC3 characterised as Lyn(-)RORc(-)Tbet(+) NKp44(+) cells were significantly expanded in the gut, SF and BM of patients with AS compared with controls, produced high levels of IL-17 and IL-22 and expressed α4β7. MADcAM1 was overexpressed in BM and ileal high endothelial venules. IL-7 was significantly increased in AS gut, especially in the context of Paneth cells, and accompanied by the presence of aggregates of c-kit/IL-7R(+) cells (LTi). In in vitro experiments, epithelial cells from patients with AS actively induced differentiation of ILC3 from LTi. TNFi efficacy was accompanied by a significant decrease in the percentage of intestinal and circulating ILC3 and in the expression of MADCAM1.

CONCLUSIONS

Gut-derived IL-17(+) and IL-22(+)ILC3 are expanded in the peripheral blood, SF and inflamed BM of patients with AS, suggesting the presence of an active homing axis between the gut and the inflamed sacroiliac joints.

Interleukin-36α axis is modulated in patients with primary Sjögren's syndrome

The aim of this study was to investigate the expression of the interleukin (IL)-36 axis in patients with primary Sjögren's syndrome (pSS). Blood and minor labial salivary glands (MSG) biopsies were obtained from 35 pSS and 20 non-Sjögren's syndrome patients (nSS) patients. Serum IL-36α was assayed by enzyme-linked immunosorbent assay (ELISA). IL-36α, IL-36R, IL-36RA, IL-38, IL-22, IL-17, IL-23p19 and expression in MSGs was assessed by reverse transcription-polymerase chain reaction (RT-PCR), and tissue IL-36α and IL-38 expression was also investigated by immunohistochemistry (IHC). αβ and γδ T cells and CD68(+) cells isolated from MSGs were also studied by flow cytometry and confocal microscopy analysis. IL-36α was over-expressed significantly in the serum and in the salivary glands of pSS. Salivary gland IL-36α expression was correlated with the expression levels of IL-17, IL-22 and IL-23p19. IL-38, that acts as inhibitor of IL-36α, was also up-regulated in pSS. αβ(+) CD3(+) T cells and CD68(+) cells were the major source of IL-36α in minor salivary glands of pSS. γδ T cells were not significantly expanded in the salivary glands of pSS but produced more IL-17, as their percentage correlated with the focus score. Higher expression of IL-36α and IL-36R was also demonstrated in γδ T cells isolated from pSS compared to controls. In this study we demonstrate that a significant increase in circulating and tissue levels of IL-36α occurs in pSS patients.

Interleukin (IL)-22 receptor 1 is over-expressed in primary Sjogren's syndrome and Sjögren-associated non-Hodgkin lymphomas and is regulated by IL-18

The aim of this study was to elucidate more clearly the role of interleukin (IL)-18 in modulating the IL-22 pathway in primary Sjögren's syndrome (pSS) patients and in pSS-associated lymphomas. Minor salivary glands (MSGs) from patients with pSS and non-specific chronic sialoadenitis (nSCS), parotid glands biopsies from non-Hodgkin lymphomas (NHL) developed in pSS patients, were evaluated for IL-18, IL-22, IL-22 receptor 1 (IL-22R1), IL-22 binding protein (IL-22BP) and signal transducer and activator of transcription-3 (STAT-3) expression. MSGs IL-22R1-expressing cells were characterized by confocal microscopy and flow cytometry in pSS, nSCS and healthy controls . The effect of recombinant IL-18 and IL-22 on peripheral blood mononuclear cells (PBMCs) from pSS and nSCS was studied by flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR). MSGs of pSS and NHL were characterized by an imbalance between IL-22 and IL-22BP protein expression, with IL-18 and IL-22BP being expressed in a mutually exclusive manner and IL-18 and IL-22R1 being correlated directly. Aberrant expression of IL-22R1, induced by IL-18, was observed only among tissue and circulating myeloid cells of pSS patients and macrophages of NHL tissues of pSS patients, but not nSCS. IL-22R1 expression on PBMC of pSS was functional, as its stimulation with recombinant IL-22 significantly up-regulated the expression of STAT-3, IL-17 and IL-22. An IL-18-dependent aberrant expression of IL-22R1 on cells of haematopoietic origin seems to be a specific immunological signature of patients with pSS and pSS-associated lymphomas.

Potential involvement of IL-9 and Th9 cells in the pathogenesis of rheumatoid arthritis

OBJECTIVE

IL-9 has been shown to be upregulated before the clinical onset of articular disease in RA. The exact role of IL-9 and Th9 cells in RA, however, has not yet been adequately studied. The aim of this study was to evaluate the expression of IL-9 and IL-9-expressing cells in RA patients.

METHODS

IL-9, IL-9R, PU.1, IL-9, thymic stromal lymphopoietin (TSLP), IL-4 and TGF-β expression was assessed by real-time-PCR in the synovial tissues of RA and OA patients. IL-9, IL-9R, IL-4, TSLP and TGF-β were also investigated by immunohistochemistry. Peripheral CD4(+) T cell subsets were studied by flow cytometry analysis before and after incubation with citrullinated peptides.

RESULTS

IL-9 was overexpressed in RA synovial tissues and correlated with the degree of histological organization of B and T cells in ectopic lymphoid structures. The majority of IL-9-producing cells were identified as CD3(+) cells. Increased mRNA and protein expression of IL-9R, IL-4, TSLP and TGF-β was also observed in RA synovial tissue. Blood peripheral Th9 cells were expanded by citrullinated peptides.

CONCLUSION

These results indicate that Th9 cells and IL-9 were frequently detected in peripheral blood mononuclear cells and synovia of RA patients. A possible pathogenic role for Th9 in RA is discussed.

Granzyme A as a potential biomarker of Mycobacterium tuberculosis infection and disease

Cytotoxic molecules such as granulysin, perforin and granzymes produced by cytolytic T cells directly contribute to immune defense against tuberculosis (TB). In search for novel TB biomarkers, we have evaluated the levels of granzyme A in plasma obtained from QuantiFERON-TB Gold In tube (QFT-IT) assays from patients with active TB disease and subjects with latent TB infection (LTBI). Granzyme A serum levels in TB patients were significantly lower than values found in LTBI subjects even after subtraction of the unstimulated levels from the antigen-stimulated responses. The receiver operator characteristics (ROC) curve analysis comparing TB patients and LTBI groups, showed that at a cut-off value of granzyme A of <3.425pg/ml, the sensitivity and the specificity of the assay were 29.41% and 94.74%, respectively. Our results suggest that granzyme A could be considered another biomarker of TB, that can be used, other than IFN-γ, to discriminate between patients with active TB and LTBI subjects in a well characterized cohort of confirmed Mycobacterium tuberculosis-infected individuals.

Peripheral frequency of CD4+ CD28- cells in acute ischemic stroke: relationship with stroke subtype and severity markers

CD4+ CD28- T cells also called CD28 null cells have been reported as increased in the clinical setting of acute coronary syndrome. Only 2 studies previously analyzed peripheral frequency of CD28 null cells in subjects with acute ischemic stroke but, to our knowledge, peripheral frequency of CD28 null cells in each TOAST subtype of ischemic stroke has never been evaluated. We hypothesized that CD4+ cells and, in particular, the CD28 null cell subset could show a different degree of peripheral percentage in subjects with acute ischemic stroke in relation to clinical subtype and severity of ischemic stroke.The aim of our study was to analyze peripheral frequency of CD28 null cells in subjects with acute ischemic stroke in relation to TOAST diagnostic subtype, and to evaluate their relationship with scores of clinical severity of acute ischemic stroke, and their predictive role in the diagnosis of acute ischemic stroke and diagnostic subtypeWe enrolled 98 consecutive subjects admitted to our recruitment wards with a diagnosis of ischemic stroke. As controls we enrolled 66 hospitalized patients without a diagnosis of acute ischemic stroke. Peripheral frequency of CD4+ and CD28 null cells has been evaluated with a FACS Calibur flow cytometer.Subjects with acute ischemic stroke had a significantly higher peripheral frequency of CD4+ cells and CD28 null cells compared to control subjects without acute ischemic stroke. Subjects with cardioembolic stroke had a significantly higher peripheral frequency of CD4+ cells and CD28 null cells compared to subjects with other TOAST subtypes. We observed a significant relationship between CD28 null cells peripheral percentage and Scandinavian Stroke Scale and NIHSS scores. ROC curve analysis showed that CD28 null cell percentage may be useful to differentiate between stroke subtypes.These findings seem suggest a possible role for a T-cell component also in acute ischemic stroke clinical setting showing a different peripheral frequency of CD28 null cells in relation of each TOAST subtype of stroke.