Macrophage dysfunction in Psoriatic Arthritis

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Increased Frequency and Compromised Function of T Regulatory Cells in Systemic Sclerosis (SSc) Is Related to a Diminished CD69 and TGFβ Expression

Contains fulltext : 80239.pdf (publisher's version ) (Open Access)BACKGROUND: Regulatory T cells (Tregs) are essential in the control of tolerance. Evidence implicates Tregs in human autoimmune conditions. Here we investigated their role in systemic sclerosis (SSc). METHODS/PRINCIPAL FINDINGS: Patients were subdivided as having limited cutaneous SSc (lcSSc, n = 20) or diffuse cutaneous SSc (dcSSc, n = 48). Further subdivision was made between early dcSSc (n = 24) and late dcSSc (n = 24) based upon the duration of disease. 26 controls were studied for comparison. CD3+ cells were isolated using FACS and subsequently studied for the expression of CD4, CD8, CD25, FoxP3, CD127, CD62L, GITR, CD69 using flow cytometry. T cell suppression assays were performed using sorted CD4CD25(high)CD127(-) and CD4CD25(low)CD127(high) and CD3(+) cells. Suppressive function was correlated with CD69 surface expression and TGFbeta secretion/expression. The frequency of CD4(+)CD25(+) and CD25(high)FoxP3(high)CD127(neg) T cells was highly increased in all SSc subgroups. Although the expression of CD25 and GITR was comparable between groups, expression of CD62L and CD69 was dramatically lower in SSc patients, which correlated with a diminished suppressive function. Co-incubation of Tregs from healthy donors with plasma from SSc patients fully abrogated suppressive activity. Activation of Tregs from healthy donors or SSc patients with PHA significantly up regulated CD69 expression that could be inhibited by SSc plasma. CONCLUSIONS/SIGNIFICANCE: These results indicate that soluble factors in SSc plasma inhibit Treg function specifically that is associated with altered Treg CD69 and TGFbeta expression. These data suggest that a defective Treg function may underlie the immune dysfunction in systemic sclerosis

Impaired dendritic cell proinflammatory cytokine production in psoriatic arthritis

Item does not contain fulltextOBJECTIVE: The pathogenesis of psoriatic arthritis (PsA) remains poorly understood. The underlying chronic inflammatory immune response is thought to be triggered by unknown environmental factors potentially arising from a defective immune function. We undertook this study to determine whether an impaired acute inflammatory response by dendritic cells (DCs) might compromise the clearance of bacteria and predispose to chronic inflammation. METHODS: We determined cytokine production by DCs from healthy controls and from patients with rheumatoid arthritis, PsA, and psoriasis in response to Mycobacterium tuberculosis, Mycobacterium avium paratuberculosis, and a range of other bacteria and Toll-like receptor (TLR) ligands. Phenotypic differences involved in cellular responses against (myco)bacteria were determined by quantitative polymerase chain reaction and flow cytometry. RESULTS: The secretion of proinflammatory cytokines by PsA DCs was impaired upon in vitro challenge with mycobacteria and TLR-2 ligands. This impairment was associated with elevated serum levels of C-reactive protein. The expression of TLR-2 and other receptors known to mediate mycobacterial recognition was unaltered. In contrast, the intracellular TLR inhibitors suppressor of cytokine signaling 3 and A20 were more highly expressed in DCs from PsA patients. PsA DCs further demonstrated up-regulated levels of ATG16L1, NADPH oxidase 2, and LL37, which are molecules implicated in the immune response against intracellular bacteria. CONCLUSION: Our findings indicate that DCs from PsA patients have a disordered immune response toward some species of (myco)bacteria. This might predispose to impaired immune responses to, and in turn impaired clearance of, these bacteria, setting the stage for the chronic inflammation of joints, entheses, skin, and the gut

Differential expansion of circulating human MDSC subsets in patients with cancer, infection and inflammation

Background Myeloid-derived suppressor cells (MDSC) are a functional myeloid cell subset that includes myeloid cells with immune suppressive properties. The presence of MDSC has been reported in the peripheral blood of patients with several malignant and non-malignant diseases. So far, direct comparison of MDSC across different diseases and Centers is hindered by technical pitfalls and a lack of standardized methodology. To overcome this issue, we formed a network through the COST Action Mye-EUNITER (www.mye-euniter.eu) with the goal to standardize and facilitate the comparative analysis of human circulating MDSC in cancer, inflammation and infection. In this manuscript, we present the results of the multicenter study Mye-EUNITER MDSC Monitoring Initiative, that involved 13 laboratories and compared circulating MDSC subsets across multiple diseases, using a common protocol for the isolation, identification and characterization of these cells. Methods We developed, tested, executed and optimized a standard operating procedure for the isolation and immunophenotyping of MDSC using blood from healthy donors. We applied this procedure to the blood of almost 400 patients and controls with different solid tumors and non-malignant diseases. The latter included viral infections such as HIV and hepatitis B virus, but also psoriasis and cardiovascular disorders. Results We observed that the frequency of MDSC in healthy donors varied substantially between centers and was influenced by technical aspects such as the anticoagulant and separation method used. Expansion of polymorphonuclear (PMN)-MDSC exceeded the expansion of monocytic MDSC (M-MDSC) in five out of six solid tumors. PMN-MDSC expansion was more pronounced in cancer compared with infection and inflammation. Programmed death-ligand 1 was primarily expressed in M-MDSC and e-MDSC and was not upregulated as a consequence of disease. LOX-1 expression was confined to PMN-MDSC. Conclusions This study provides improved technical protocols and workflows for the multi-center analysis of circulating human MDSC subsets. Application of these workflows revealed a predominant expansion of PMN-MDSC in solid tumors that exceeds expansion in chronic infection and inflammation

Soluble Immune Complexes Shift the TLR-Induced Cytokine Production of Distinct Polarized Human Macrophage Subsets towards IL-10

Contains fulltext : 109563.pdf (publisher's version ) (Open Access)BACKGROUND: Costimulation of murine macrophages with immune complexes (ICs) and TLR ligands leads to alternative activation. Studies on human myeloid cells, however, indicate that ICs induce an increased pro-inflammatory cytokine production. This study aimed to clarify the effect of ICs on the pro- versus anti-inflammatory profile of human polarized macrophages. MATERIALS AND METHODS: Monocytes isolated from peripheral blood of healthy donors were polarized for four days with IFN-gamma, IL-4, IL-10, GM-CSF, M-CSF, or LPS, in the presence or absence of heat aggregated gamma-globulins (HAGGs). Phenotypic polarization markers were measured by flow cytometry. Polarized macrophages were stimulated with HAGGs or immobilized IgG alone or in combination with TLR ligands. TNF, IL-6, IL-10, IL-12, and IL-23 were measured by Luminex and/or RT-qPCR. RESULTS: HAGGs did not modulate the phenotypic polarization and the cytokine production of macrophages. However, HAGGs significantly altered the TLR-induced cytokine production of all polarized macrophage subsets, with the exception of MPhi(IL-4). In particular, HAGGs consistently enhanced the TLR-induced IL-10 production in both classically and alternatively polarized macrophages (M1 and M2). The effect of HAGGs on TNF and IL-6 production was less pronounced and depended on the polarization status, while IL-23p19 and IL-12p35 expression was not affected. In contrast with HAGGs, immobilized IgG induced a strong upregulation of not only IL-10, but also TNF and IL-6. CONCLUSION: HAGGs alone do not alter the phenotype and cytokine production of in vitro polarized human macrophages. In combination with TLR-ligands, however, HAGGs but not immobilized IgG shift the cytokine production of distinct macrophage subsets toward IL-10

Splenic TFH expansion participates in B-cell differentiation and antiplatelet-antibody production during immune thrombocytopenia

Antiplatelet-antibody-producing B cells play a key role immune thrombocytopenia (ITP) pathogenesis; however, little is known about T-cell dysregulations that support B-cell differentiation. During the past decade, T follicular helper cells (TFHs) have been characterized as the main T-cell subset within secondary lymphoid organs that promotes B-cell differentiation leading to antibody class-switch recombination and secretion. Herein, we characterized TFHs within the spleen of 8 controls and 13 ITP patients. We show that human splenic TFHs are the main producers of interleukin (IL)-21, express CD40 ligand(CD154), and are located within the germinal center of secondary follicles. Compared with controls, splenic TFH frequency is higher in ITP patients and correlates with germinal center and plasma cell percentages that are also increased. In vitro, IL-21 stimulation combined with an anti-CD40 agonist antibody led to the differentiation of splenic B cells into plasma cells and to the secretion of antiplatelet antibodies in ITP patients. Overall, these results point out the involvement of TFH in ITP pathophysiology and the potential interest of IL-21 and CD40 as therapeutic targets in ITP

A Systematic Review of Immunological Studies of Erythema Nodosum Leprosum.

Erythema nodosum leprosum (ENL) is a painful inflammatory complication of leprosy occurring in 50% of lepromatous leprosy patients and 5-10% of borderline lepromatous patients. It is a significant cause of economic hardship, morbidity and mortality in leprosy patients. Our understanding of the causes of ENL is limited. We performed a systematic review of the published literature and critically evaluated the evidence for the role of neutrophils, immune complexes (ICs), T-cells, cytokines, and other immunological factors that could contribute to the development of ENL. Searches of the literature were performed in PubMed. Studies, independent of published date, using samples from patients with ENL were included. The search revealed more than 20,000 articles of which 146 eligible studies were included in this systematic review. The studies demonstrate that ENL may be associated with a neutrophilic infiltrate, but it is not clear whether it is an IC-mediated process or that the presence of ICs is an epiphenomenon. Increased levels of tumor necrosis factor-α and other pro-inflammatory cytokines support the role of this cytokine in the inflammatory phase of ENL but not necessarily the initiation. T-cell subsets appear to be important in ENL since multiple studies report an increased CD4+/CD8+ ratio in both skin and peripheral blood of patients with ENL. Microarray data have identified new molecules and whole pathophysiological pathways associated with ENL and provides new insights into the pathogenesis of ENL. Studies of ENL are often difficult to compare due to a lack of case definitions, treatment status, and timing of sampling as well as the use of different laboratory techniques. A standardized approach to some of these issues would be useful. ENL appears to be a complex interaction of various aspects of the immune system. Rigorous clinical descriptions of well-defined cohorts of patients and a systems biology approach using available technologies such as genomics, epigenomics, transcriptomics, and proteomics could yield greater understanding of the condition

Dysregulated Expression of Both the Costimulatory CD28 and Inhibitory CTLA-4 Molecules in PB T Cells of Advanced Cervical Cancer Patients Suggests Systemic Immunosuppression Related to Disease Progression

Cervical cancer (CC) occurs more frequently in women who are immunosuppressed, suggesting that both local and systemic immune abnormalities may be involved in the evolution of the disease. Costimulatory CD28 and inhibitory CTLA-4 molecules expressed in T cells play a key role in the balanced immune responses. There has been demonstrated a relation between CD28, CTLA-4, and IFN genes in susceptibility to CC, suggesting their importance in CC development. Therefore, we assessed the pattern of CD28 and CTLA-4 expression in T cells from PB of CC patients with advanced CC (stages III and IV according to FIGO) compared to controls. We also examined the ability of PBMCs to secrete IFN-gamma. We found lower frequencies of freshly isolated and ex vivo stimulated CD4 + CD28+ and CD8 + CD28+ T cells in CC patients than in controls. Loss of CD28 expression was more pronounced in the CD8+ T subset. Markedly increased proportions of CTLA-4+ T cells in CC patients before and after culture compared to controls were also observed. In addition, patients’ T cells exhibited abnormal kinetics of surface CTLA-4 expression, with the peak at 24 h of stimulation, which was in contrast to corresponding normal T cells, revealing maximum CTLA-4 expression at 72 h of stimulation. Of note, markedly higher IFN-gamma concentrations were shown in supernatants of stimulated PBMCs from CC patients. Conclusions: Our report shows the dysregulated CD28 and CTLA-4 expression in PB T cells of CC patients, which may lead to impaired function of these lymphocytes and systemic immunosuppression related to disease progression