Intestinal-borne dermatoses significantly improved by oral application of Escherichia coli Nissle 1917

AIM: To evaluate the effect of oral Escherichia coli (E. coli) Nissle application on the outcome of intestinal-borne dermatoses.

METHODS: In a randomized, controlled, non-blinded prospective clinical trial 82 patients with intestinal-borne facial dermatoses characterized by an erythematous papular-pustular rash were screened. At the initiation visit 37 patients entered the experimental arm and 20 patients constituted the control arm. All 57 patients were treated with a vegetarian diet and conventional topical therapy of the dermatoses with ointments containing tetracycline, steroids and retinoids. In the experimental arm patients received a one month therapy with oral E. coli Nissle at a maintenance dose of 2 capsules daily. The experimental group was compared to a non-treatment group only receiving the diet and topical therapy. The primary outcome parameter was improvement of the dermatoses, secondary parameters included life quality and adverse events. In addition the immunological reaction profile (IgA, interleucin-8 and interferon-α) was determined. Furthermore the changes of stool consistency and the microbiota composition over the time of intervention were recorded.

RESULTS: Eighty-nine percent of the patients with acne, papular-pustular rosacea and seborrhoic dermatitis responded to E. coli Nissle therapy with significant amelioration or complete recovery in contrast to 56% in the control arm (P < 0.01). Accordingly, in the E. coli Nissle treated patients life quality improved significantly (P < 0.01), and adverse events were not recorded. The clinical improvement was associated with a significant increase of IgA levels to normal values in serum as well as suppression of the proinflammatory cytokine IL-8 (P < 0.01 for both parameters). In the E. coli Nissle treated group a shift towards a protective microbiota with predominance of bifidobacteria and lactobacteria (> 10⁷ CFU/g stool) was observed in 79% and 63% of the patients, respectively (P < 0.01), compared to no change in the control group without E. coli Nissle. Moreover, the detection rate of a pathogenic flora dropped from 73% to 14 % of the patients in the experimental arm (P < 0.01) with no significant change in the control arm (accounting 80% before and 70% after the observation period, P > 0.05). Accordingly, stool consistency, color and smell normalized in the E. coli Nissle treated patients.

CONCLUSION: E. coli Nissle protects the mucus barrier by overgrowth of a favorable gut microbiota with less immunoreactive potential which finally leads to clinical improvement of intestinal borne dermatoses.

Type I and III IFNs Produced by Plasmacytoid Dendritic Cells in Response to a Member of the Flaviviridae Suppress Cellular Immune Responses

The pestivirus noncytopathic bovine viral diarrhea virus (BVDV) can suppress IFN production in the majority of cell types in vitro. However, IFN is detectable in serum during acute infection in vivo for ∼5-7 d, which correlates with a period of leucopoenia and immunosuppression. In this study, we demonstrate that a highly enriched population of bovine plasmacytoid dendritic cells (DCs) produced IFN in response to BVDV in vitro. We further show that the majority of the IFN produced in response to infection both in vitro and in vivo is type III IFN and acid labile. Further, we show IL-28B (IFN-λ3) mRNA is induced in this cell population in vitro. Supernatant from plasmacytoid DCs harvested postinfection with BVDV or recombinant bovine IFN-α or human IL-28B significantly reduced CD4(+) T cell proliferation induced by tubercle bacillus Ag 85-stimulated monocyte-derived DCs. Furthermore, these IFNs induced IFN-stimulated gene expression predominantly in monocyte-derived DCs. IFN-treated immature DCs derived from murine bone marrow also had a reduced capacity to stimulate T cell proliferative responses to tubercle bacillus Ag 85. Immature DCs derived from either source had a reduced capacity for Ag uptake following IFN treatment that is dose dependent. Immunosuppression is a feature of a number of pestivirus infections; our studies suggest type III IFN production plays a key role in the pathogenesis of this family of viruses. Overall, in a natural host, we have demonstrated a link between the induction of type I and III IFN after acute viral infection and transient immunosuppression.

A cytotoxic anti-IL-3Rα antibody targets key cells and cytokines implicated in systemic lupus erythematosus

To date, the major target of biologic therapeutics in systemic lupus erythematosus (SLE) has been the B cell, which produces pathogenic autoantibodies. Recently, targeting type I IFN, which is elaborated by plasmacytoid dendritic cells (pDCs) in response to endosomal TLR7 and TLR9 stimulation by SLE immune complexes, has shown promising results. pDCs express high levels of the IL-3Rα chain (CD123), suggesting an alternative potential targeting strategy. We have developed an anti-CD123 monoclonal antibody, CSL362, and show here that it affects key cell types and cytokines that contribute to SLE. CSL362 potently depletes pDCs via antibody-dependent cell-mediated cytotoxicity, markedly reducing TLR7, TLR9, and SLE serum-induced IFN-α production and IFN-α-upregulated gene expression. The antibody also inhibits TLR7- and TLR9-induced plasmablast expansion by reducing IFN-α and IL-6 production. These effects are more pronounced than with IFN-α blockade alone, possibly because pDC depletion reduces production of other IFN subtypes, such as type III, as well as non-IFN proinflammatory cytokines, such as IL-6. In addition, CSL362 depletes basophils and inhibits IL-3 signaling. These effects were confirmed in cells derived from a heterogeneous population of SLE donors, various IFN-dependent autoimmune diseases, and healthy controls. We also demonstrate in vivo activity of CSL362 following its s.c. administration to cynomolgus monkeys. This spectrum of effects provides a preclinical rationale for the therapeutic evaluation of CSL362 in SLE.

Classical Swine Fever Virus vs. Classical Swine Fever Virus: The Superinfection Exclusion Phenomenon in Experimentally Infected Wild Boar

Two groups with three wild boars each were used: Group A (animals 1 to 3) served as the control, and Group B (animals 4 to 6) was postnatally persistently infected with the Cat01 strain of CSFV (primary virus). The animals, six weeks old and clinically healthy, were inoculated with the virulent strain Margarita (secondary virus). For exclusive detection of the Margarita strain, a specific qRT-PCR assay was designed, which proved not to have cross-reactivity with the Cat01 strain. The wild boars persistently infected with CSFV were protected from superinfection by the virulent CSFV Margarita strain, as evidenced by the absence of clinical signs and the absence of Margarita RNA detection in serum, swabs and tissue samples. Additionally, in PBMCs, a well-known target for CSFV viral replication, only the primary infecting virus RNA (Cat01 strain) could be detected, even after the isolation in ST cells, demonstrating SIE at the tissue level in vivo. Furthermore, the data analysis of the Margarita qRT-PCR, by means of calculated ΔCt values, supported that PBMCs from persistently infected animals were substantially protected from superinfection after in vitro inoculation with the Margarita virus strain, while this virus was able to infect naive PBMCs efficiently. In parallel, IFN-α values were undetectable in the sera from animals in Group B after inoculation with the CSFV Margarita strain. Furthermore, these animals were unable to elicit adaptive humoral (no E2-specific or neutralising antibodies) or cellular immune responses (in terms of IFN-γ-producing cells) after inoculation with the second virus. Finally, a sequence analysis could not detect CSFV Margarita RNA in the samples tested from Group B. Our results suggested that the SIE phenomenon might be involved in the evolution and phylogeny of the virus, as well as in CSFV control by vaccination. To the best of our knowledge, this study was one of the first showing efficient suppression of superinfection in animals, especially in the absence of IFN-α, which might be associated with the lack of innate immune mechanisms.

Th17 Cytokines Disrupt the Airway Mucosal Barrier in Chronic Rhinosinusitis

Cytokine mediated changes in paracellular permeability contribute to a multitude of pathological conditions including chronic rhinosinusitis (CRS). The purpose of this study was to investigate the effect of interferons and of Th1, Th2, and Th17 cytokines on respiratory epithelium barrier function. Cytokines and interferons were applied to the basolateral side of air-liquid interface (ALI) cultures of primary human nasal epithelial cells (HNECs) from CRS with nasal polyp patients. Transepithelial electrical resistance (TEER) and permeability of FITC-conjugated dextrans were measured over time. Additionally, the expression of the tight junction protein Zona Occludens-1 (ZO-1) was examined via immunofluorescence. Data was analysed using ANOVA, followed by Tukey HSD post hoc test. Our results showed that application of interferons and of Th1 or Th2 cytokines did not affect the mucosal barrier function. In contrast, the Th17 cytokines IL-17, IL-22, and IL-26 showed a significant disruption of the epithelial barrier, evidenced by a loss of TEER, increased paracellular permeability of FITC-dextrans, and discontinuous ZO-1 immunolocalisation. These results indicate that Th17 cytokines may contribute to the development of CRSwNP by promoting a leaky mucosal barrier.

ALTERATION OF OXIDATIVE METABOLISM AND IMMUNOLOGICAL PARAMETERS UNDER THE INFLUENCE OF UVA RADIATION IN WOMEN OF DIFFERENT AGES

Purpose of study was to investigate the alteration of oxidative and immunological metabolism in blood of reproductive and menopausal age women after UVA irradiation. Women of two groups (1 - menopausal, 2 - reproductive age) were exposed to radiation with wave length 320-400 nm for 5-10 minutes per session in the solarium for the period of 3 months (6 days per month).. Parameters of oxidative metabolism - activity of red blood cells (RBC), antioxidant enzymes catalase (CAT) and superoxiddismutase (SOD) were studied by spectrophotometric method; reactive oxygen (O2-) and lipid (LOO/) free radicals content in whole blood were studied by Electron Paramagnetic Resonance (EPR) methods with use of specific spin-traps - 5,5-Dimethyl-1-Pyrroline-N-Oxide (DMPO) and α-phenyl-N-tert-butylnitrone (PBN) (SIGMA). Parameters of immunological metabolism - IFN-α, IL-2, IL-10 cytokines content in blood were studied by immunoenzymatic assay ELISA. The study protocol has been approved by the Ethical Committee of the Tbilisi State Medical University. After the course of UVA irradiation in menopausal women CAT activity increased by 20%, SOD - by 24%, and EPR signal of spin trapped lipoperoxide radicals was detected. No alterations in blood redox-balance were detected in women of reproductive age. Values of blood immunological parameters in menopausal women were not changed under the influence of UV radiation; in women of reproductive age IL-10 content increase by 93% (within a normal value range) was revealed. Research results have shown that UVA rays cause a particularly significant influence on the oxidative metabolism in the women of menopausal age. Increase of IL-10 blood levels in women of reproductive age (considering its imunosupressing activity) represents an additional risk of cancerogenesis. Based on the study results, we recommend avoiding UV (including UVA) radiation procedures to women of both reproductive and menopausal ages.

Enhancing Pharmacokinetics, Tumor Accumulation, and Antitumor Efficacy by Elastin-Like Polypeptide Fusion of Interferon Alpha

Genetic fusion of elastin-like polypeptide (ELP) to the C-terminus of interferon alpha (IFN) generates a well-defined IFN-ELP fusion protein with high yield and well-retained bioactivity. The fusion protein significantly enhances pharmacokinetics, tumor accumulation, and antitumor efficacy of interferon alpha in a murine cancer model.

Osteoclast Differentiation Is Impaired in a Subgroup of SLE Patients and Correlates Inversely with Mycophenolate Mofetil Treatment

Osteoporosis can arise in systemic lupus erythematosus (SLE) patients secondary to medication and/or chronic inflammation. To analyze if patients with SLE have phenotypically-impaired osteoclastogenesis, we differentiated ex vivo monocytes from 72 SLE patients and 15 healthy individuals into osteoclasts followed by TRAP staining and counting. We identified a subgroup of SLE patients (45%) with a significantly impaired osteoclast differentiation, relative to the other SLE patients or healthy individuals (OR 11.2; 95% CI 1.4–89.9). A review of medication indicated that patients with osteoclast counts equal to healthy donors were significantly more likely to be treated with mycophenolate mofetil (MMF) compared to patients with impaired osteoclastogenesis. We analyzed expression of RANKL and the MMF target genes IMPDH1 and IMPDH2 in osteoclasts by qPCR, but detected no difference. Since MMF might influence interferon-α (IFNα) and -γ (IFNγ) we measured serum IFNα and IFNγ levels. Patients with very low osteoclast counts also had comparably higher IFNα serum levels than patients with normal osteoclast counts. We conclude that in vitro osteoclastogenesis is impaired in a subgroup of SLE patients. This correlates inversely with MMF treatment and high IFNα serum levels. Further observational study will be required to determine whether this translates into a clinically meaningful effect.

Almond Skin Inhibits HSV-2 Replication in Peripheral Blood Mononuclear Cells by Modulating the Cytokine Network

We have investigated the effect of almond skin extracts on the production of pro-inflammatory and anti-inflammatory cytokines in human peripheral blood mononuclear cells (PBMCs). PBMCs were either infected or not by herpes simplex virus type 2 (HSV-2), with and without prior treatment with almond skin extracts. Production of IL-17 induced by HSV-2 was inhibited by natural skins (NS) treatment. NS triggered PBMC in releasing IFN-α, IFN-γ and IL-4 in cellular supernatants. These results may explain the antiviral potential of almond skins.

Induction dosing of peginterferon alfa-2a (40 KD) and/or high-dose ribavirin in genotype 1 CHC patients with difficult-to-treat characteristics: pharmacokinetic and viral kinetic (PK/VK) assessment from PROGRESS

BACKGROUND/AIMS

PROGRESS randomized chronic hepatitis C genotype 1 patients with a baseline viral load ≥400,000 IU/mL weighing ≥85 kg to regimens of 180 μg/week for 48 weeks or 360 μg/week for 12 weeks followed by 180 μg/week for 36 weeks peginterferon alfa-2a plus ribavirin. This analysis explored pharmacokinetics and early viral kinetics (VK) and evaluates differences between groups.

METHODOLOGY

Blood samples for pharmacokinetic and VK analyses were collected from 51 patients enrolled in the PROGRESS study.

RESULTS

Mean peginterferon alfa-2a trough concentration at week 12 was 11.7±4.3 ng/mL for 180 μg and 23.4±11.3 ng/mL for 360 μg. Early VK profiles suggested a trend towards an enhanced viral decline in the 360 μg groups with a mean decrease in HCV RNA at 48 hours post first dose of 1.04 log10 (IU/mL) compared with 0.76 log10 (IU/mL) in the 180 μg groups. Mean beta slope increased with dose, ranging from 0.38±0.26 log10 IU/week at 180 μg to 0.52±0.32 log10 IU/week at 360 μg.

CONCLUSIONS

Early viral de clines may be enhanced with the 360 μg dose. These data may suggest the utility of high-dose peginterfer on alfa-2a plus direct-acting antivirals (DAA) in select difficult-to-treat populations.

microRNA146a expression in lupus patients with and without renal complications

microRNA146a (miRNA) expression profiles are likely to become important diagnostic and prognostic tools in many disease aspects. This work aimed to study the expression of miRNA146a in lupus patients with and without renal complications and to assess its association with disease activity. Patients enrolled in the study included 52 females affected by systemic lupus erythematosus (SLE) and another 60 females with lupus nephritis (LN). Forty-eight age-matched healthy females were enrolled as a control group. miRNA146a expression was assessed using real-time PCR. In SLE patients, miRNA146a was underexpressed as compared to healthy controls and lower levels were detected among lupus patients with renal affection. In addition, miRNA146a expression was low and serum Interferon-α (IFN-α) level was high in patients with active lupus as compared to those with inactive disease. miRNA146a expression was inversely correlated to serum IFN-α level and to anti ds-DNA titer in the three studied groups. In conclusion, miRNA146a might be implicated in lupus pathogenesis. Moreover, miRNA146a expression correlates negatively to lupus activity and LN, whereas serum IFN-α has a direct correlation to both disease activity and nephritis; hence, both miRNA146a expression and serum IFN-α could be potentially important diagnostic biomarkers and potential novel strategies for therapeutic interventions, which may possibly be implied to enhance the sensitivity and specificity for the prediction of flares and prognosis in SLE patients.

The preventive effects of natural adjuvants, G2 and G2F on tracheal responsiveness and serum IL-4 and IFN-γ (th1/th2 balance) in sensitized guinea pigs

OBJECTIVE

The effects of natural adjuvants on lung inflammation and tracheal responsiveness were examined in sensitized guinea pigs.

METHODS

The responses of guinea pig tracheal chains and the serum levels of interleukin-4 and interferon-gamma were examined in control pigs and three other groups of guinea pigs: the sensitized group and two other sensitized groups treated with either adjuvant G2 or adjuvant G2F (n=7 for each group). Sensitization of the animals was achieved by injection and inhalation of ovalbumin.

RESULTS

The results showed that sensitized animals had increased tracheal responsiveness and increased serum levels of interleukin-4 and interferon-gamma compared to controls (p<0.05 to p<0.001). Treatments with either G2 or G2F prevented the increase in tracheal responsiveness and serum interleukin-4 (p<0.01 to p<0.001). However, the serum levels of interferon-gamma and the interleukin-4-to-interferon-gamma ratio was increased in the treated groups (p<0.001 for all cases).

CONCLUSIONS

These results indicate important preventive effects of two natural adjuvants, particularly G2, on the changes in tracheal responsiveness, serum cytokines and the interleukin-4-to-interferon-gamma ratio (T helper 1/T helper 2 balance) in sensitized guinea pigs.

c-FLIP-Short reduces type I interferon production and increases viremia with coxsackievirus B3

Cellular FLIP (c-FLIP) is an enzymatically inactive paralogue of caspase-8 and as such can block death receptor-induced apoptosis. However, independent of death receptors, c-FLIP-Long (c-FLIP_L) can heterodimerize with and activate caspase-8. This is critical for promoting the growth and survival of T lymphocytes as well as the regulation of the RIG-I helicase pathway for type I interferon production in response to viral infections. Truncated forms of FLIP also exist in mammalian cells (c-FLIP_S) and certain viruses (v-FLIP), which lack the C-terminal domain that activates caspase-8. Thus, the ratio of c-FLIP_L to these short forms of FLIP may greatly influence the outcome of an immune response. We examined this model in mice transgenically expressing c-FLIP_S in T cells during infection with Coxsackievirus B3 (CVB3). In contrast to our earlier findings of reduced myocarditis and mortality with CVB3 infection of c-FLIP_L-transgenic mice, c-FLIP_S-transgenic mice were highly sensitive to CVB3 infection as manifested by increased cardiac virus titers, myocarditis score, and mortality compared to wild-type C57BL/6 mice. This observation was paralleled by a reduction in serum levels of IL-10 and IFN-α in CVB3-infected c-FLIP_S mice. In vitro infection of c-FLIP_S T cells with CVB3 confirmed these results. Furthermore, molecular studies revealed that following infection of cells with CVB3, c-FLIP_L associates with mitochondrial antiviral signaling protein (MAVS), increases caspase-8 activity and type I IFN production, and reduces viral replication, whereas c-FLIP_S promotes the opposite phenotype.

A strong interferon response correlates with a milder dengue clinical condition

BACKGROUND

Type 1 interferon (IFNα/β) has a significant role in establishing protection against virus infections. It has been well documented by in vitro studies that dengue virus (DENV) activates a robust IFNα/β response. However, DENV also induces a down-regulation of the JAK/STAT pathway, inhibiting the induction of interferon regulated genes. As a consequence, the role played by the IFN type 1 response in the protection of dengue patients is not fully understood.

OBJECTIVE

To compare IFN-α levels in dengue patients with dengue fever (DF) or dengue hemorrhagic fever (DHF) undergoing primary or secondary infections.

STUDY DESIGN

Two hundred and four serum samples were analyzed for IFN-α level by cytometric bead array. Patients' clinical condition was assigned following the WHO 1997 criteria and specific IgG and IgM antibodies were measured using commercial assays to determine primary and secondary infections. The infecting serotype was determined by qRT-PCR.

RESULTS AND CONCLUSION

The IFN-α levels were found significantly higher in DF than DHF patients irrespective of the infecting serotype (DENV1 or 2), and were found to decline rapidly at day 3 after fever onset. For DENV2 infections, higher IFN-α level was found during primary than secondary infections. These results suggest that an early strong interferon response correlates with a better clinical condition.

IFNα serum levels are associated with endothelial progenitor cells imbalance and disease features in rheumatoid arthritis patients

Introduction

IFNα has been largely implicated in the ethiopathogenesis of autoimmune diseases but only recently it has been linked to endothelial damage and accelerated atherosclerosis in autoimmunity. In addition, proinflammatory conditions are supposed to be implicated in the cardiovascular status of these patients. Since a role for IFNα in endothelial damage and impaired Endothelial Progenitor Cell (EPC) number and function has been reported in other diseases, we aimed to evaluate the potential associations of IFNα serum levels on EPC populations and cytokine profiles in Rheumatoid Arthritis (RA) patients.

Methods

pre-EPC, EPC and mature EPC (mEPC) populations were quantified by flow cytometry analyzing their differential CD34, CD133 and VEGFR2 expression in blood samples from 120 RA patients, 52 healthy controls (HC), and 83 systemic lupus erythematosus (SLE) patients as disease control. Cytokine serum levels were measured by immunoassays and clinical and immunological data, including cardiovascular (CV) events and CV risk factors, were retrospectively obtained by reviewing clinical records.

Results

Long-standing, but not recent onset RA patients displayed a significant depletion of all endothelial progenitor populations, unless high IFNα levels were present. In fact, the IFN^high RA patient group (n = 40, 33%), showed increased EPC levels, comparable to SLE patients. In addition, high IFNα serum levels were associated with higher disease activity (DAS28), presence of autoantibodies, higher levels of IL-1β, IL-6, IL-10 and MIP-1α, lower amounts of TGF-β, and increased mEPC/EPC ratio, thus suggesting higher rates of endothelial damage and an endothelial repair failure. Finally, the relationship between high IFNα levels and occurrence of CV events observed in RA patients seems to support this hypothesis.

Conclusions

IFNα serum marker could be used to identify a group of RA patients with increased disease activity, EPC imbalance, enhanced proinflammatory profile and higher cardiovascular risk, probably due, at least in part, to an impaired endothelial repair.

Measuring interferon alpha and other cytokines in SLE

The progression of disease in patients with systemic lupus erythematosus (SLE) is affected by production, accumulation, and actions of cytokines. Type I interferon (IFN), specifically IFN-α, is recognized as a central mediator of disease pathogenesis in SLE. We describe a functional assay to measure type I IFN activity in SLE plasma and have also measured the response of peripheral blood cells to that cytokine family. This method can be scaled to assess IFN functional activity, as well as activity and cellular response to other cytokines, in relation to cellular and serologic parameters relevant to SLE.

[Interferon inductor activity and interferon production under the action of acridonacetic acid salts]

Peculiarities of the kinetics of accumulation and duration of circulation of three types of interferon under the action of acridonacetic acid salts have been studied. Optimum doses of meglumine salt of acridonacetic acid are established, which ensure efficient and consistent induction of three interferon types, ensuring their prolonged circulation in the blood.

[Induction of type 1, 2 and 3 interferons by acridone acetates]

The induction profile of endogenous interferons of three types under the action of meglumine acridone acetate and sodium acridone acetate, as well as the characteristics of the kinetics of their accumulation and circulation in the blood of experimental animals are described. Meglumine acridone acetate provided balance in induction, production and circulation of the interferons in the blood vs. sodium aeridone acetate under the same conditions. The optimal dose of meglumine acridone acetate (2.0-3.5 mg/mouse) with effective, consecutive and overlapping induction-production of the interferons ensured their prolonged (for 72 hours) circulation in the blood after a single administration.

[Activation of hypomethylated DNA on plasmacytoid dendritic cells in patients with systemic lupus erythematosus]

OBJECTIVE

To explore the activation of hypomethylated DNA on plasmacytoid dendritic cells (pDC) in patients with systemic lupus erythematosus (SLE).

METHODS

Peripheral blood mononuclear cells (PBMC) were isolated from whole blood of SLE patients and healthy controls. The methylation level of DNA and the expression of DNA methyltransferase 1 (DNMT1) mRNA were detected. Flow cytometry was used to detect the expression of CD32 on pDC and the serum concentration of interferon-alpha (IFN-α) measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The DNA methylation level from SLE patients (1.4 ± 0.6) % was lower than that of controls (1.8 ± 0.7) % (P < 0.01). The expression of DNMT1 mRNA significantly decreased in SLE patients (0.06 ± 0.03) versus the controls (0.09 ± 0.02) (P < 0.01). The CD32 expression on pDC from SLE patients (29 ± 19)% was higher than that from controls (18.02 ± 7.80)% (P < 0.01). The serum level of IFN-α in SLE patients (4.5 ± 6.7) ng/L was significantly higher than that of controls (2.1 ± 2.0) ng/L (P < 0.01). The methylation level of DNA in SLE patients was positively correlated with the expression of DNMT1 mRNA (r = 0.257, P < 0.05) and negatively with the expression of CD32 (r = -0.358, P < 0.01) and IFN-α (r = -0.280, P < 0.05).

CONCLUSIONS

The methylation level of genomic DNA decreases in SLE patients due to the down-regulated expression of DNMT1 gene. Hypomethylated DNA may be translocated intracellularly via endocytic receptor (CD32) on pDC. And the activation of pDC is induced to produce IFN-α so as to participate in the onset of SLE.

Influence of Atg5 mutation in SLE depends on functional IL-10 genotype

Increasing evidence supports the involvement of autophagy in the etiopathology of autoimmune diseases. Despite the identification of autophagy-related protein (Atg)-5 as one of the susceptibility loci in systemic Lupus erythematosus (SLE), the consequences of the carriage of these mutations for patients remain unclear. The present work analyzed the association of Atg5 rs573775 single nucleotide polymorphism (SNP) with SLE susceptibility, IFNα, TNFα and IL-10 serum levels, and clinical features, in 115 patients and 170 healthy individuals. Patients who where carriers of the rs573775 T* minor allele presented lower IFNα levels than those with the wild genotype, whereas the opposite result was detected for IL-10. Thus, since IL-10 production was regulated by rs1800896 polymorphisms, we evaluated the effect of this Atg5 mutation in genetically high and low IL-10 producers. Interestingly, we found that the rs573775 T* allele was a risk factor for SLE in carriers of the high IL-10 producer genotype, but not among genetically low producers. Moreover, IL-10 genotype influences SLE features in patients presenting the Atg5 mutated allele. Specifically, carriage of the rs573775 T* allele led to IL-10 upregulation, reduced IFNα and TNFα production and a low frequency of cytopenia in patients with the high IL-10 producer genotype, whereas patients with the same Atg5 allele that were low IL-10 producers presented reduced amounts of all these cytokines, had a lower prevalence of anti-dsDNA antibodies and the latest onset age. In conclusion, the Atg5 rs573775 T* allele seems to influence SLE susceptibility, cytokine production and disease features depending on other factors such as functional IL-10 genotype.

Anti-NKG2A autoantibodies in a patient with systemic lupus erythematosus

OBJECTIVES

To characterize a novel anti-NKG2A autoantibody detected in a patient with SLE during a severe flare, and in a cross-sectional study investigate the occurrence of such autoantibodies in patients with SLE and primary SS (pSS).

METHODS

Serum or IgG from patients with SLE, pSS and healthy volunteers were assayed for blocking of anti-NKG2A or HLA-E binding to peripheral blood mononuclear cells or CD94/NKG2A- and CD94/NKG2C-transfected Ba/F3 cells. The anti-NKG2A autoantibodies were evaluated for effect on NK cell degranulation in response to HLA-E-transfected K562 cells. IFN-α was determined by an immunoassay and disease activity by the SLEDAI score.

RESULTS

Anti-NKG2A autoantibodies, which blocked binding of HLA-E tetramers to CD94/NKG2A-transfected cells and impaired NKG2A-mediated inhibition of NK cell activation, were observed in a patient with SLE. The presence of anti-NKG2A autoantibodies was associated with high SLE disease activity (SLEDAI score 14 and 16) and increased serum IFN-α. Of 94 SLE, 60 pSS and 30 healthy donor sera, only the index patient serum contained anti-NKG2A autoantibodies.

CONCLUSION

The presence of autoantibodies targeting NKG2A is a rare event, but when such autoantibodies occur they may promote excessive NK cell function. This can contribute to the pathogenesis by increasing the killing of cells and the release of autoantigens. Our findings highlight the possible importance of NK cells in the SLE disease process.

Interferon-α induction and detection of anti-ro, anti-la, anti-sm, and anti-rnp autoantibodies by autoantigen microarray analysis in juvenile dermatomyositis

OBJECTIVE

To evaluate serum interferon-α (IFNα) activity in the context of autoantibody profiles in patients with juvenile dermatomyositis (JDM).

METHODS

Sera from 36 patients with JDM were analyzed. Autoantibody profiles were determined by probing microarrays, which were fabricated with ∼80 distinct autoantigens, with serum and a Cy3-conjugated secondary antibody. Arrays were scanned and analyzed to determine antigen reactivity. Serum IFNα activity was measured using a functional reporter cell assay. Sera were assayed alone or in combination with cellular material released from necrotic U937 cells to stimulate peripheral blood mononuclear cells from healthy donors in vitro, and IFNα production in culture was measured by a dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA).

RESULTS

Reactivity against at least 1 of 41 autoantigens on the microarray, including Ro 52, Ro 60, La, Sm, and RNP, was observed in 75% of the serum samples from patients with JDM. IFNα activity was detected in 7 samples by reporter cell assay. The reporter cell assay showed a significant association of reactivity against Ro, La, Sm, and proliferating cell nuclear antigen with serum IFNα activity (P = 0.005). Significance Analysis of Microarrays (SAM) identified increased reactivity against Sm, RNP, Ro 52, U1-C, and Mi-2 in these sera. Sixteen samples induced IFNα production as measured by DELFIA, and there was a significant association of reactivity against Ro, La, Sm, and RNP with the induction of IFNα by serum and necrotic cell material (P = 0.034). SAM identified increased reactivity against Ro 60 in these sera.

CONCLUSION

These data support the hypothesis that nucleic acid-associated autoantibodies, including the Ro/La and Sm/RNP complexes, may stimulate the production of active IFNα in children with JDM.

Blocking TLR7- and TLR9-mediated IFN-α production by plasmacytoid dendritic cells does not diminish immune activation in early SIV infection

Persistent production of type I interferon (IFN) by activated plasmacytoid dendritic cells (pDC) is a leading model to explain chronic immune activation in human immunodeficiency virus (HIV) infection but direct evidence for this is lacking. We used a dual antagonist of Toll-like receptor (TLR) 7 and TLR9 to selectively inhibit responses of pDC but not other mononuclear phagocytes to viral RNA prior to and for 8 weeks following pathogenic simian immunodeficiency virus (SIV) infection of rhesus macaques. We show that pDC are major but not exclusive producers of IFN-α that rapidly become unresponsive to virus stimulation following SIV infection, whereas myeloid DC gain the capacity to produce IFN-α, albeit at low levels. pDC mediate a marked but transient IFN-α response in lymph nodes during the acute phase that is blocked by administration of TLR7 and TLR9 antagonist without impacting pDC recruitment. TLR7 and TLR9 blockade did not impact virus load or the acute IFN-α response in plasma and had minimal effect on expression of IFN-stimulated genes in both blood and lymph node. TLR7 and TLR9 blockade did not prevent activation of memory CD4+ and CD8+ T cells in blood or lymph node but led to significant increases in proliferation of both subsets in blood following SIV infection. Our findings reveal that virus-mediated activation of pDC through TLR7 and TLR9 contributes to substantial but transient IFN-α production following pathogenic SIV infection. However, the data indicate that pDC activation and IFN-α production are unlikely to be major factors in driving immune activation in early infection. Based on these findings therapeutic strategies aimed at blocking pDC function and IFN-α production may not reduce HIV-associated immunopathology.

A persistent type I interferon (IFN) response is thought to be important in driving immune activation and progression to AIDS in human immunodeficiency virus (HIV)-infected individuals. Plasmacytoid dendritic cells (pDC) produce copious amounts of type I IFN upon virus exposure through engagement of Toll-like receptor (TLR) 7 and TLR9 and thus may be central players in the etiology of immune activation. We used a dual antagonist of TLR7 and TLR9 to selectively block the response of pDC but not other mononuclear phagocytes prior to and for 8 weeks following simian immunodeficiency virus (SIV) infection of rhesus macaques. We show that pDC are major, but not exclusive, producers of IFN-α that mediate a marked but transient IFN-α response in lymph nodes in the acute phase of infection. TLR7 and TLR9 antagonist prevented this IFN-α production without suppressing pDC recruitment. Nevertheless, TLR7 and TLR9 blockade did not impact expression of IFN-stimulated genes or decrease the activation of T cells, the hallmarks of immune activation. The findings indicate that TLR7 and TLR9-driven activation of pDC is unlikely to be a major contributor to immune activation in the early stages of immunodeficiency virus infections and suggest that therapeutic strategies aimed at targeting pDC and IFN-α production may not reduce HIV-associated immunopathology.

β-Defensin 2 and 3 promote the uptake of self or CpG DNA, enhance IFN-α production by human plasmacytoid dendritic cells, and promote inflammation

Alarmins are a group of structurally diverse host defense antimicrobial peptides that are important immune activators. In this article, we present a novel role for two potent alarmins, human β-defensin 2 and 3 (HBD2 and 3), in promoting IFN-α production by human plasmacytoid dendritic cells. We demonstrate that HBD2 and 3 activate pDCs by enhancing the intracellular uptake of CpG and self DNA and promote DNA-induced IFN-α production in a TLR9-dependent manner. Both CpG and host DNA form aggregates that resemble DNA nets when combined with HBD2 and 3. Isothermal titration calorimetry studies to elucidate the nature of HBD3/CpG complexes demonstrate involvement of enthalpy-driven interactions, in addition to hydrophobic interactions, with the formation of complexes at a molar ratio of 2:1 defensin/CpG. The i.v. administration of HBD3/CpG complexes induced proinflammatory cytokines like IL-12, IFN-γ, IL-6, IFN-α, and IL-10 in serum, associated with an increased recruitment of APCs in the spleen. Subcutaneous injections of these complexes showed enhanced infiltration of inflammatory cells at the injection site, indicating a potential pathophysiological role for alarmin/DNA complexes in contributing to inflammation. Intraperitoneal immunization of HBD3/CpG complexes with OVA enhanced both cellular and humoral responses to OVA, compared with OVA/HBD3 or OVA/CPG alone, indicative of a much more potent adjuvant effect of the HBD3/CpG complexes. Thus, the ability of defensins to enhance cellular uptake of nucleic acids can lead to improved vaccine formulations by promoting their uptake by various cells, resulting in an enhanced immune response.

Dengue virus activates membrane TRAIL relocalization and IFN-α production by human plasmacytoid dendritic cells in vitro and in vivo

Background

Dengue displays a broad spectrum of clinical manifestations that may vary from asymptomatic to severe and even fatal features. Plasma leakage/hemorrhages can be caused by a cytokine storm induced by monocytes and dendritic cells during dengue virus (DENV) replication. Plasmacytoid dendritic cells (pDCs) are innate immune cells and in response to virus exposure secrete IFN-α and express membrane TRAIL (mTRAIL). We aimed to characterize pDC activation in dengue patients and their function under DENV-2 stimulation in vitro.

Methods & Findings

Flow cytometry analysis (FCA) revealed that pDCs of mild dengue patients exhibit significantly higher frequencies of mTRAIL compared to severe cases or healthy controls. Plasma levels of IFN-α and soluble TRAIL are increased in mild compared to severe dengue patients, positively correlating with pDC activation. FCA experiments showed that in vitro exposure to DENV-2 induced mTRAIL expression on pDC. Furthermore, three dimension microscopy highlighted that TRAIL was relocalized from intracellular compartment to plasma membrane. Chloroquine treatment inhibited DENV-2-induced mTRAIL relocalization and IFN-α production by pDC. Endosomal viral degradation blockade by chloroquine allowed viral antigens detection inside pDCs. All those data are in favor of endocytosis pathway activation by DENV-2 in pDC. Coculture of pDC/DENV-2-infected monocytes revealed a dramatic decrease of antigen detection by FCA. This viral antigens reduction in monocytes was also observed after exogenous IFN-α treatment. Thus, pDC effect on viral load reduction was mainly dependent on IFN-α production

Conclusions

This investigation characterizes, during DENV-2 infection, activation of pDCs in vivo and their antiviral role in vitro. Thus, we propose TRAIL-expressing pDCs may have an important role in the outcome of disease.

Dengue is an important endemic tropical disease to which there are no specific therapeutics or approved vaccines. Currently several aspects of pathophysiology remain incompletely understood. A crucial cellular population for viral infections, the plasmacytoid dendritic cells (pDCs) was analyzed in this study. The authors found an in vivo association between the activation state of pDCs and the disease outcome. Membrane TNF-related apoptosis inducing ligand (TRAIL) expressing pDCs, representing activated pDCs, were found in higher frequency in milder cases of dengue than severe cases or healthy individuals. Detection of antiviral cytokine interferon-alpha (IFN-α) and soluble TRAIL positively correlated with pDC activation. Dengue virus (DENV) serotype-2 was able to directly activate pDCs in vitro. Under DENV stimulation TRAIL was relocalized from intracellular to pDC plasma membrane and IFN-α was highly produced. The authors suggest an endocytosis-dependent pathway for DENV-induced pDC activation. It is also highlighted here a role for exogenous IFN-α and pDCs in reducing viral replication in monocytes, one of DENV main target cells. These findings may contribute in the future to the establishment of good prognostic immune responses together with clinical manifestations/warning signs.