Low IFN Research Articles

Genetic analysis of the pathogenic molecular sub-phenotype interferon-alpha identifies multiple novel loci involved in systemic lupus erythematosus.

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disorder characterized by inflammation of multiple organ systems and dysregulated interferon responses. SLE is both genetically and phenotypically heterogeneous, greatly reducing the power of case-control studies in SLE. Elevated circulating interferon alpha (IFN-α) is a stable, heritable trait in SLE, which has been implicated in primary disease pathogenesis. 40–50% of patients have high IFN-α, and high levels correspond with clinical differences. To study genetic heterogeneity in SLE, we performed a case-case study comparing patients with high vs. low IFN-α in over 1550 SLE cases, including GWAS and replication cohorts. In meta-analysis, the top associations in European ancestry were PRKG1 rs7897633 (PMeta=2.75 × 10−8) and PNP rs1049564 (PMeta=1.24 × 10−7). We also found evidence for cross-ancestral background associations with the ANKRD44 and PLEKHF2 loci. These loci have not been previously identified in case-control SLE genetic studies. Bioinformatic analyses implicated these loci functionally in dendritic cells and natural killer cells, both of which are involved in IFN-α production in SLE. As case-control studies of heterogeneous diseases reach a limit of feasibility with respect to subject number and detectable effect size, the study of informative pathogenic subphenotypes becomes an attractive strategy for genetic discovery in complex disease.

Enhanced in Vivo Efficacy of a Type I Interferon Superagonist with Extended Plasma Half-life in a Mouse Model of Multiple Sclerosis

IFNβ is a common therapeutic option to treat multiple sclerosis. It is unique among the family of type I IFNs in that it binds to the interferon receptors with high affinity, conferring exceptional biological properties. We have previously reported the generation of an interferon superagonist (dubbed YNSα8) that is built on the backbone of a low affinity IFNα but modified to exhibit higher receptor affinity than even for IFNβ. Here, YNSα8 was fused with a 600-residue hydrophilic, unstructured N-terminal polypeptide chain comprising proline, alanine, and serine (PAS) to prolong its plasma half-life via "PASylation." PAS-YNSα8 exhibited a 10-fold increased half-life in both pharmacodynamic and pharmacokinetic assays in a transgenic mouse model harboring the human receptors, notably without any detectable loss in biological potency or bioavailability. This long-lived superagonist conferred significantly improved protection from MOG35-55-induced experimental autoimmune encephalomyelitis compared with IFNβ, despite being injected with a 4-fold less frequency and at an overall 16-fold lower dosage. These data were corroborated by FACS measurements showing a decrease of CD11b(+)/CD45(hi) myeloid lineage cells detectable in the CNS, as well as a decrease in IBA(+) cells in spinal cord sections determined by immunohistochemistry for PAS-YNSα8-treated animals. Importantly, PAS-YNSα8 did not induce antibodies upon repeated administration, and its biological efficacy remained unchanged after 21 days of treatment. A striking correlation between increased levels of CD274 (PD-L1) transcripts from spleen-derived CD4(+) cells and improved clinical response to autoimmune encephalomyelitis was observed, indicating that, at least in this mouse model of multiple sclerosis, CD274 may serve as a biomarker to predict the effectiveness of IFN therapy to treat this complex disease.

73: Enhanced in vivo efficacy using a novel long-life type I interferon variant in a mouse model of multiple sclerosis

IFN β is a common therapeutic option to treat multiple sclerosis (MS). It is unique amongst the family of type I IFNs in that it binds to the interferon receptors with high affinity, conferring exceptional biological properties. We have previously reported the generation of an interferon superagonist (dubbed YNS α 8) that is built on the backbone of a low affinity IFN, but modified to exhibit higher receptor affinity than IFN β . Here, YNS α 8 was fused with a 600-residue hydrophilic, unstructured N-terminal polypeptide chain, comprising Proline, Alanine and Serine (PAS), in order to prolong its plasma half-life via “PASylation”. PAS-IFN α 8 exhibited a 10-fold increased half-life in both pharmacodynamic and pharmacokinetic assays in a transgenic mouse model harboring the human receptors [1] , notably without any detectable loss in biological potency or bioavailability. This long-life superagonist conferred significantly improved protection from MOG35–55 peptide-induced experimental autoimmune encephalomyelitis (EAE) compared to IFN β , despite being injected with a 4-fold decrease in frequency and at an overall 16-fold lower dosage. These data were corroborated by FACS and immunohistochemistry, showing a decrease of myeloid lineage cells in the central nervous system (CNS) for PAS-YNS α 8 treated animals. Importantly, PAS-IFN α 8 did not induce antibodies upon repeated administration, and its biological efficacy remained unchanged after 21 days of treatment. We next extracted RNA from spleen-derived CD4 + cells and performed high throughput qPCR for ∼ 200 IFN-response genes enriched for immune function. A striking strong correlation of gene expression and EAE clinical response was observed for two genes - CD274 (PD-L1) and CXCR3. An IFN-responsive role for PD-L1 in EAE clinical response has been recently reported elsewhere [2] . This preclinical study thus supports that we have generated a novel, potent and pharmacologically long-acting IFN-variant with potential to treat multiple sclerosis with greater efficacy than current IFN therapies available for use today. It is also provides us with a means to unravel the central IFN-response genes that are providing clinical benefit in EAE and potentially for MS.

The Novel Human Influenza A(H7N9) Virus Is Naturally Adapted to Efficient Growth in Human Lung Tissue

ABSTRACTA novel influenza A virus (IAV) of the H7N9 subtype has been isolated from severely diseased patients with pneumonia and acute respiratory distress syndrome and, apparently, from healthy poultry in March 2013 in Eastern China. We evaluated replication, tropism, and cytokine induction of the A/Anhui/1/2013 (H7N9) virus isolated from a fatal human infection and two low-pathogenic avian H7 subtype viruses in a human lung organ culture system mimicking infection of the lower respiratory tract. The A(H7N9) patient isolate replicated similarly well as a seasonal IAV in explanted human lung tissue, whereas avian H7 subtype viruses propagated poorly. Interestingly, the avian H7 strains provoked a strong antiviral type I interferon (IFN-I) response, whereas the A(H7N9) virus induced only low IFN levels. Nevertheless, all viruses analyzed were detected predominantly in type II pneumocytes, indicating that the A(H7N9) virus does not differ in its cellular tropism from other avian or human influenza viruses. Tissue culture-based studies suggested that the low induction of the IFN-β promoter correlated with an efficient suppression by the viral NS1 protein. These findings demonstrate that the zoonotic A(H7N9) virus is unusually well adapted to efficient propagation in human alveolar tissue, which most likely contributes to the severity of lower respiratory tract disease seen in many patients.

72 : EGR2 is critical for peripheral Naïve T cell differentiation and the T-cell mediated response to influenza

EGR1 and EGR2 are closely related members of an early growth response family of transcription factors, with EGR1 generally considered to be a positive regulator and EGR2 a negative regulator of T cell activation, promoting T cell anergy while decreasing autoimmunity. Here, we have studied the roles of these factors during influenza infection and unexpectedly found that EGR2, but not EGR1, is required for peripheral naive T cell differentiation and T cell-mediated immune responses. Deletion of either the Egr1 or Egr2 gene delayed TCR-induced proliferation of peripheral naive CD4+ and CD8+ T cells, with Egr2 -deficient T cells having lower proliferation and cytokine expression than Egr1 -deficient T cells, with lower IFN- γ , IL-4, IL-9, and IL-17A expression under Th1, Th2, Th9, and Th17 conditions, respectively. Moreover, Egr2 was necessary for T cellmediated immune responses to influenza infection, with delayed virus clearance, greater weight loss, and more severe pathologic changes in Egr2 conditional KO (CKO) mice than in WT or Egr1 KO mice. The Egr2 CKO mice also had defective CD4+ T cell immune responses, with dysregulated cytokine expression and augmented infiltration of antigen-specific CD8+ T cells that had a memory precursor phenotype and decreased cytolytic activity. Collectively, these results unexpectedly reveal that EGR2 is an essential transcriptional regulator for the differentiation of naive T cells and a critical positive regulator of the normal T cell-mediated immune response to influenza infection.

Phase I Trial of Intravesical Recombinant Adenovirus Mediated Interferon-α2b Formulated in Syn3 for Bacillus Calmette-Guérin Failures in Nonmuscle Invasive Bladder Cancer

A phase I trial of intravesical recombinant adenovirus mediated interferon-α2b gene therapy (rAd-IFNα) formulated with the excipient SCH Syn3 was conducted in patients with nonmuscle invasive bladder cancer who had disease recurrence after treatment with bacillus Calmette-Guérin. The primary objective was to determine the safety of rAd-IFNα/Syn3. Secondary end points were demonstrated effective rAd-IFNα gene expression and preliminary evidence of clinical activity at 3 months. A total of 17 patients with recurrent nonmuscle invasive bladder cancer after bacillus Calmette-Guérin treatment were enrolled in the study. A single treatment of rAd-IFNα (3 × 10(9) to 3 × 10(11) particles per ml) formulated with the excipient Syn3 was administered. Patient safety was evaluated for 12 or more weeks. Efficacy of gene transfer was determined by urine IFNα protein concentrations. Preliminary drug efficacy was determined at 3 months. Intravesical rAd-IFNα/Syn3 was well tolerated as no dose limiting toxicity was encountered. Urgency was the most common adverse event and all cases were grade 1 or 2. rAd-IFNα DNA was not detected in the blood. However, transient low serum IFNα and Syn3 levels were measured. High and prolonged dose related urine IFNα levels were achieved with the initial treatment. Of the 14 patients treated at doses of 10(10) or more particles per ml with detectable urine IFNα, 6 (43%) experienced a complete response at 3 months and 2 remained disease-free at 29.0 and 39.2 months, respectively. Intravesical rAd-IFNα/Syn3 was well tolerated with no dose limiting toxicity encountered. Dose dependent urinary IFNα concentrations confirmed efficient gene transfer and expression. Intravesical rAd-IFNα/Syn3 demonstrated clinical activity in nonmuscle invasive bladder cancer recurring after bacillus Calmette-Guérin.

BST2/Tetherin inhibits hepatitis C virus production in human hepatoma cells

Hepatitis C virus (HCV) infection is a common cause of chronic hepatitis and is currently treated with alpha interferon (IFN-α)-based therapies. IFN-induced cell membrane protein BST2 (also known as CD317, HM1.24 or tetherin) has been reported to tether a broad range of lipid-enveloped viruses on cell surfaces. However, whether HCV is sensitive to BST2 remains controversial. Here we established a Huh7.5-BST2-TO cell line, in which BST2 expression is regulated by tetracycline. Our results showed that the effect of BST2 on inhibiting HCV production was dependent on its expression level. Highly expressed BST2 reduced the yield of cell-free HCV virions but did not affect the efficiency of HCV infection and genome replication. Co-localization of HCV core protein and BST2 was detected by immunofluorescence in certain cells with high expression, but not in cells with low BST2 expression. Furthermore, inhibition of IFN-α induced BST2 expression in Huh7.5 cells by siRNA technology slightly reduced the antiviral response of the cytokine against HCV, but only at low IFN-α concentration. While overexpression of BST2 inhibited HCV replication in this system, BST2 is therefore not likely to be a major contributor to the antiviral effect of IFN-α.

Role of microRNA-15a in autoantibody production in interferon-augmented murine model of lupus

MicroRNAs (miRNAs) are involved in the regulation of immunity via targeting of mRNA encoding immune response elements. In this report, alterations in the expression of microRNAs as autoantibody levels increase was investigated. The (NZB×NZW)F1 or B/W mouse model of systemic lupus erythematosus (SLE) naturally has increased autoantibodies with aging. IFNα (type I IFN) accelerates B/W disease, however, the effects of a related IFN, IFNλ, which is a type III IFN, is largely unknown. The purpose of the study was to investigate the relationship between IFN-accelerated disease, microRNAs, immunoregulatory B cell subsets and autoantibody production in the autoimmune-prone environment in vivo. B/W mice received osmotic pumps to chronically deliver IFNα and IFNλ for up to 16 weeks. Urine protein level was monitored weekly by urine strips and proteinuria was used as the disease marker. Splenic cells were taken for flow analysis of B cell subsets and levels of microRNAs determined. Plasma were analyzed for autoantibodies and microRNA levels. As a result of treatment, IFNα accelerated proteinuria in a dose dependent manner, while IFNλ single treatment did not show a significant effect, but greatly enhanced low dose IFNα effects in the combination treatment. Both the splenic cellular and plasma miR-15a were elevated in diseased compared to pre-diseased mice as well as autoantibody levels. Autoantibodies and miR-15a levels were significantly correlated. The immunosuppressive B subpopulation, B-10, was reduced following IFNα treatment. In addition in diseased mice, B-10 versus B-2 ratios were reduced in IFN-treated B/W compared to the control PBS treated group. In all B/W the miR-15a was highly expressed in the B-10 subset and this increased with disease development, suggesting that miR-15a has a specific negative effect on the B-10 subpopulation. In conclusion, our data support the involvement of elevated miR-15a in autoimmune disease development in B/W mice and suggest that decreasing this microRNA might be beneficial in B/W mice.

Reduced interferon (IFN)-α conditioned by IFNA2 (−173) and IFNA8 (−884) haplotypes is associated with enhanced susceptibility to severe malarial anemia and longitudinal all-cause mortality

Severe malarial anemia (SMA) is a leading cause of pediatric morbidity and mortality in holoendemic Plasmodium falciparum transmission areas. Although dysregulation in cytokine production is an important etiology of SMA, the role of IFN-α in SMA has not been reported. As such, we investigated the relationship between IFN-α promoter polymorphisms [i.e., IFNA2 (A-173T) and IFNA8 (T-884A)], SMA, and functional changes in IFN-α production in children (n = 663; <36 months) residing in a holoendemic P. falciparum transmission region of Kenya. Children with SMA had lower circulating IFN-α than malaria-infected children without severe anemia (P = 0.025). Multivariate logistic regression analyses revealed that heterozygosity at -884 (TA) was associated with an increased risk of SMA [OR 2.80 (95 % CI 1.22-6.43); P = 0.015] and reduced IFN-α relative to wild type (TT; P = 0.038). Additional analyses demonstrated that carriage of the -173T/-884A (TA) haplotype was associated with increased susceptibility to SMA [OR 3.98 (95 % CI 1.17-13.52); P = 0.026] and lower IFN-α (P = 0.031). Follow-up of these children for 36 months revealed that carriers of TA haplotype had greater all-cause mortality than non-carriers (P < 0.001). Generation of reporter constructs showed that the IFNA8 wild-type -884TT exhibited higher levels of luciferase expression than the variant alleles (P < 0.001). Analyses of malaria-associated inflammatory mediators demonstrated that carriers of TA haplotype had altered production of IL-1β, MIG, and IL-13 compared to non-carriers (P < 0.050). Thus, variation at IFNA2 -173 and IFNA8 -884 conditions reduced IFN-α production, and increased susceptibility to SMA and mortality.

Role of Cell-to-Cell Variability in Activating a Positive Feedback Antiviral Response in Human Dendritic Cells

In the first few hours following Newcastle disease viral infection of human monocyte-derived dendritic cells, the induction of IFNB1 is extremely low and the secreted type I interferon response is below the limits of ELISA assay. However, many interferon-induced genes are activated at this time, for example DDX58 (RIGI), which in response to viral RNA induces IFNB1. We investigated whether the early induction of IFNBI in only a small percentage of infected cells leads to low level IFN secretion that then induces IFN-responsive genes in all cells. We developed an agent-based mathematical model to explore the IFNBI and DDX58 temporal dynamics. Simulations showed that a small number of early responder cells provide a mechanism for efficient and controlled activation of the DDX58-IFNBI positive feedback loop. The model predicted distributions of single cell responses that were confirmed by single cell mRNA measurements. The results suggest that large cell-to-cell variation plays an important role in the early innate immune response, and that the variability is essential for the efficient activation of the IFNB1 based feedback loop.

Interferon-gamma (IFNG) and IFNGR1 Gene Variants are Associated with Atopic Dermatitis Complicated by Eczema Herpeticum (ADEH) and IFN Production

RATIONALE: Eczema herpeticum (ADEH) is a complication of atopic dermatitis (AD) associated with greater disease severity and increased IgE responses. Our studies of global gene expression have recently demonstrated that both interferon-gamma (IFNG) and IFNG receptor (IFNGR1) are down-regulated in ADEH patients. Association between genetic variants in IFNG and IFN production has been previously reported. We investigated whether IFNG and IFNGR1 gene variants are associated with ADEH and low IFN production by PBMCs from ADEH patients following stimulation with herpes simplex virus (HSV).

Effect of conventional interferon‐α in patients with HBeAg‐positive chronic hepatitis B: a systematic review and meta‐analysis

Although a few studies have tested the effect of interferon-α on chronic hepatitis B, its treatment effect remains uncertain, and the association of treatment effect with intervention characteristics has not been thoroughly explored. This study examined the effect of IFN-α in patients with HBeAg-positive chronic hepatitis B, and investigated the characteristics associated with treatment effect. We searched MEDLINE, Scientific Citation Index, Current Content Connect, Cochrane Controlled Trial Register, and Chinese Biomedical Database, all up to 15 September 2009. We included randomized trials comparing IFN-α to placebo, no treatment, or standard care (SC) in patients with HBeAg-positive chronic hepatitis B. Two reviewers assessed the risk of bias and extracted data, independently and in duplicate. We conducted meta-analyses of the included studies, and subgroup analyses to examine the association of pre-specified characteristics (eg, dose, treatment duration) with treatment effect. A total of 31 randomized controlled trials, involving 2164 patients, were included. The risk of bias varied across studies. Compared with placebo, no treatment, or SC, IFN-α improved loss of HBeAg (OR 2.36, 95% CI 1.83 to 3.04), HBV DNA undetectability (OR 2.04, 95% CI 1.28 to 3.32), HBeAg seroconversion (OR 1.82, 95% CI 1.26 to 2.62), ALT normalization (OR 1.24, 95% CI 1.01 to 1.56), and loss of HBsAg (OR 2.45, 95% CI 1.22 to 4.91). Treatment effects differed in high versus low dose, and long versus short duration of IFN-α. The effect of high dose IFN-α (OR 3.28, 95% CI 2.31 to 4.66) is statistically larger than that of low dose IFN-α (OR 1.58, 95% CI 1.10 to 2.28) on loss of HBeAg (interaction P = 0.017), and longer IFN-α treatment durations produce greater effects (OR 3.28, 95% CI 2.16 to 5.00) than do shorter durations (OR 1.94, 95% CI 0.42 to 2.66, interaction P = 0.038). High dose IFN-α had a significant effect on HBV DNA undetectability (OR 2.80, 95% CI 2.03 to 3.86), while low dose IFN-α did not (OR 0.93, 95% CI 0.61 to 1.41, interaction P = 0.01); longer treatments significantly improved HBV DNA undetectability (OR 2.58, 95% CI 1.62 to 4.12), but shorter durations did not (OR 1.28, 95% CI 0.83 to 1.97, interaction P = 0.024). IFN-α can improve serological, biomedical, and virological response. Higher doses and prolonged treatments appear to have larger treatment benefits than lower doses and shorter treatments. However, the increased adverse reactions and costs associated with higher doses and prolonged treatment warrant caution in applying these results.

Adjuvant therapy with pegylated interferon alfa-2b (36 months) versus low-dose interferon alfa-2b (18 months) in melanoma patients without macro-metastatic nodes: EADO trial.

LBA8506 Background: Adjuvant therapy with low-dose adjuvant interferon alfa-2b (IFN) as well as with pegylated interferon alfa-2b (PEG-IFN) were both shown to be superior to observation in melanoma (M) patients (pts) without macro-metastatic nodes. However, the two strategies have never been assessed head to head. Weekly injection of PEG-IFN facilitates a longer duration of treatment which may be critical for benefit. We thus compared adjuvant therapy of flat low-dose PEG-IFN (36 months) versus low-dose IFN (18 months) in intermediate-risk M pts without macro-metastatic nodes. Methods: In this multicenter, open-label, prospective randomized phase III trial, pts with resected M ≥ 1.5 mm in thickness and without clinically detectable nodes were randomized either to IFN (3 MU subcutaneously [sc] 3 times a week for 18 months) or to PEG-IFN (100 mcg sc once weekly for 36 months). Sentinel node procedure (SNP) was not a standard in 2003 and thus was optional. Approach was consistent by center. Randomization was stratified for centers and SNP procedure. Primary endpoint was relapse-free survival (RFS), and secondary were distant metastasis-free survival (DMFS), overall survival (OS), and grade 3-4 severe adverse events (SAE). Sample size (890 pts) was calculated to detect a 10% difference (power &gt;80%, type I error of 5%, 2-sided) for RFS. Analysis describes 5-year probability of survival. Comparisons were done by intent-to-treat using Cox proportional models. Results: Of 898 pts enrolled, 896 (443 PEG vs 453 IFN) were eligible for evaluation after a median follow-up of 4.7 years. SLNB was performed in 68.2% of pts. Neither RFS (PEG-IFN 66.2% vs IFN 64.8%, p=0.43; HR, 0.91; 95% CI, 0.73 to 1.15) nor DMFS (71.3% vs 72.6%, p=0.86; HR, 1.02; 95% CI, 0.80 to 1.32) or OS (77.0% vs 78.4%, p=0.55; HR, 1.09; 95% CI, 0.82 to 1.45) showed statistical difference. There was an excess of SAE grade 3-4 in PEG-IFN arm (44.6% vs 26.6% in the first 18 months) which impacted on median duration of treatment (17.8 months in IFN arm; 19.2 in PEG-IFN arm, with only 28% completing 36 months treatment). Conclusions: Flat low-dose PEG-IFN did not show superiority over conventional low dose IFN. Attempts to increase benefit by prolonging treatment with PEG-IFN over 3 years were hampered by a high rate of treatment discontinuation possibly linked to SAEs with PEG-IFN. [Table: see text]

W1815 Immunologic Responses to Hookworm Infection in Crohn's Disease

Introduction Helminths such as hookworms survive by modulating host immune responses as a strategy to escape the host9s defence mechanisms.1 Hookworm infection is demonstrated by a polarised Th2 response, releasing characteristic cytokines (IL-4, IL-5, IL-10, IL-13). Conversely, Crohn9s disease is characterised by a Th1 response, releasing pro-inflammatory cytokines (TNF, IFN, IL-2)2. The reciprocal inhibition of cytokine products between distinct T helper cell responses, has led to studies of hookworms as adjuncts to immunosuppressants in Crohn9s disease.2 The Nottingham Digestive Diseases Centre recently completed a placebo-controlled trial on the effect of hookworms on disease activity in Crohn9s disease, providing an opportunity to study changes in T cell populations. Methods Blood samples were obtained at four time points during the trial. Hookworm specific IgG was measured using ELISA methodology and confirmed by Western blot analysis. Cytokine ELISAs were carried out on IL-4, IL-5, IL-10, TNF, IFN and IL17. Regulatory T cells were measured by flow cytometry utilising CD4, CD25 and Foxp3 antibodies. Results Hookworm infection was indicated by the presence of IgG–reactive 33-kDa bands on Western Blots, and was confirmed by an eosinophilia and positive faecal egg counts. Cytokine ELISAs demonstrated a statistically significant increase in IL5 in the intervention group. After 6 weeks of inoculation with hookworm larvae, the mean IL5 increase from baseline in the intervention group was 515% compared to 90% in controls. Trends of reduced levels of TNF and IL-17 were observed alongside increased levels of IL-10 in the intervention group. Patients on azathioprine and steroids were found to have significantly lower IFN and IL-10 levels compared to patients not on these drugs. Conclusion Successful establishment of hookworms in patients with active Crohn9s disease is haematologically demonstrated by a heightened eosinophilic response, and supported by Western Blot analyses and faecal egg counts. Raised IL-5 levels in patients treated with hookworms also suggest a switch to an anti-helminthic Th2 response. Insights into possible collaborative effects of hookworms and immunosuppressive drugs have been demonstrated. Individual patient cytokine profiles will be correlated against CDAI scores in order to clarify whether the Th2 response confers benefits in Crohn9s disease.

Interferon signature gene expression is correlated with autoantibody profiles in patients with incomplete lupus syndromes

Interferon (IFN) signature genes have been shown to be expressed highly in peripheral blood of patients with systemic lupus erythematosus (SLE), especially in the presence of active disease. However, the expression of this gene signature in individuals with incomplete forms of lupus and the pathogenic relationship between IFN signature genes and autoantibody production have not been explored fully. In the present study, we examined the gene expression and autoantibody profiles of patients diagnosed with incomplete lupus erythematosus (ILE) to determine correlations of the gene expression signature with autoantibody production. Gene expression analysis was carried out on the 24K Illumina Human Refseq-8 arrays using blood samples from 84 subjects, including patients with SLE (n = 27) or ILE (n = 24), first-degree relatives (FDR) of these patients (n = 22) and non-autoimmune control (NC) individuals (n = 11). Autoantibody expression was measured using standard immunoassays and autoantigen proteomic arrays. Up-regulation of a set of 63 IFN signature genes was seen in 83% of SLE patients and 50% of ILE patients. High levels of IFN gene expression in ILE and SLE showed significant correlations with the expression of a subset of IgG autoantibodies, including chromatin, dsDNA, dsRNA, U1snRNP, Ro/SSA, La/SSB, topoisomerase I and Scl 70, while low IFN levels were correlated with immunoglobulin (Ig)M autoreactivity. These studies suggest that in patients with ILE the IFN gene expression signature may identify a subset of these individuals who are at risk for disease progression. Furthermore, high levels of alpha IFN may promote autoantibody class-switch from IgM to the more pathogenic IgG class.

Interferon-Alpha Preferentially Targets JAK2V617F-Positive Rather Than Wild-Type Early Progenitor Cells in Myeloproliferative Disorders.

Abstract 436Polycythemia vera (PV), essential thrombocytemia (ET) and primary myelofibrosis (PMF) are myeloproliferative disorders (MPDs) without curative treatment, unless hematopoietic stem cell (HSC) transplantation is performed. However, for several years the use of interferon-alpha (IFNα) has provided an efficient therapeutic alternative for MPD patients. IFNα was shown to induce complete long-term hematologic and molecular remissions in JAK2V617F-positive MPD patients, suggesting a possible curative effect of IFNα.In order to better understand mechanisms of action of this drug, experiments were perfomred on cell lines, patient cells and mice cells harboring a JAK2V617F mutation. We hypothesized that IFNα may target directly MPD cells through binding to its specific receptor, in addition to the potential immunological effect of this molecule and could induce cell cycle entry of the pathological quiescent HSCs.Human cell lines harboring JAK2 mutation or BCR-ABL oncogene were treated with increasing doses of IFNα. A significant anti-proliferative effect at low concentrations (100 IU/ml) on the JAK2V617F-positive HEL cell line was observed. On the contrary, at this low dose IFNα did not influence growth of the BCR-ABL-positive K562 and the non-mutated UT-7 cell lines. This result supported a direct effect of IFNα in JAK2V617F cells. Suppressor of cytokine signaling (SOCS) are potent inhibitors of the JAK-STAT pathway by proceeding to a classic negative regulation loop proteins. Following IFNα stimulation of HEL cells, SOCS1 and SOCS3 mRNAs expression were induced (p=0.00036 and p=0.0012, respectively) and efficient knock-down of either SOCS1 or SOCS3 by shRNAs expression in HEL cells was able to counteract the anti-proliferative effect of IFNα (p=0.028 and p=0.031, respectively). We concluded that SOCS1 and SOCS3 are involved, in IFNα proliferative inhibition activity of HEL cells.To determine whether JAK2V617F confer hypersensitivity to IFNα inhibitory effect, proliferation and genotyping of CD34+ progenitors isolated from the bone marrow of JAK2V617F–positive MPD patients (n=5) and control subjects (n=4) were plated at one cell per well in 96-well plates and counted and genotyped at Day 10-12. A significant decrease of the patients progenitors clonogenicity was observed when exposed to IFNα (10 000 IU/ml, p<0.05). On the contrary, normal progenitors were not sensitive to the anti-proliferative effect of IFNα (p=0.2). Patients colonies were genotyped for JAK2V617F. After IFNα exposure, the amount of homozygous JAK2V617F clones decreased in 3 over 5 patients in favor of the heterozygous JAK2V617F and/or wild-type clone(s) confirming the preferential action of IFNα on JAK2V617F progenitors. This inhibitory effect was more drastic on progenitors carrying the JAK2V617F mutation at the homozygous state.Lastly, in order to explain the long term molecular responses observed in PV patients treated by IFNα, we investigated the effect of IFNα on the cell cycle in more immature cells. BrdU assay on JAK2V617F Knock-in (KI) mice was performed. Five-months old JAK2V617F KI and wild-type mice received or not 10,000 UI of murine IFNα during 3 days. Sixteen hours before analysis, BrdU was injected i.p. in the animals. Bone marrow Lin-Sca+cKit+cells (LSK) were stained with CD150 and CD48 antibodies before BrdU labelling was analyzed by flow cytometry. Analysis of BrdU postive cells confirmed that i-JAK2V617F induces LSK CD150+CD48- to enter cell cycle ( 8.55+/-3.12% for WT cells versus 19.92+/-3,19% for JAK2V617F KI cells respectively (p = 0.04)) and ii- That IFNα induces CD150+CD48- LSK to enter cell cycle whatever the JAK2 WT (8.55+/-3.12% for non treated animals versus 15.43+/-3.19% for IFNα receiving mice (p=0.02)) or mutated status but this induction was more statistically significant in JAK2V617F mice (19.92+/-1.82% versus 25.23+/-0.57% respectively( p=0.02)).In conclusion, we gave rise to a double effect of IFNα in MPD cells: A direct preferential anti-proliferative effect of IFNα on JAK2V617F–positive MPD progenitor cells, possibly through the induction of SOCS over-expressions and a direct cell cycling effect on JAK2V617F stem cells suggesting that IFNa containing treatments could be of interest for JAK2V617F patients cure. Disclosures:No relevant conflicts of interest to declare.

Inflammatory control in AIDS-resistant non human primates

African non human primates are natural hosts of SIV. The infection is non-pathogenic despite plasma viral load levels similar to those in HIV-1 infected humans and SIVmac-infected macaques (MAC) progressing towards AIDS. The most striking difference between non-pathogenic SIV and pathogenic HIV-1/SIVmac infections is the lack of chronic T cell activation in natural hosts. In HIV and SIVmac infections, chronic T cell activation is known to drive CD4+T cell depletion. Intense research efforts are worldwide put on the search of the mechanisms that can control chronic T cell activation in HIV/SIV infections. Innate immune responses play a determinant role in the regulation of T cell activation profiles. Type I interferons (IFN-I) are part of the first-wave response of the innate immune system in viral infections. We compared the IFN-I responses between pathogenic (MAC) and non-pathogenic SIV infections (African Green monkey, AGM) at the level of blood and lymph nodes (LN) during the early and chronic stage of infection. During the acute SIVagm infection, we detected high amounts of IFN-α in the plasma of AGMs, although the mean levels at the peak were three times lower than in MAC. The microarray data revealed a rapid and strong up-regulation of type I Interferon-Stimulated Genes (ISG) in AGMs during acute SIVagm infection. ISGs denote the in vivo activity of IFN-I. Using a functional assay, we demonstrated that low IFN-α concentrations (50 times lower than the IFN-α levels in plasma at the peak) were sufficient to induce strong ISG responses in AGM and MAC cells. Surprisingly, our direct comparison of blood and LNs showed that ISG induction was broader in blood of AGMs than in MAC, while in LN, it was the contrary. Thus, in AGMs, less ISG were induced in LNs as compared to MAC already during the acute phase of infection. Moreover, our tight kinetic analysis showed that this ISG expression was efficiently controlled after day 28 post-infection in AGMs, while in MAC the ISGs expression remained uncontrolled. Finally, we identified genes that were differentially expressed between the two species and which might be involved in the discriminating responses. Altogether, this shows that AGMs are capable to mount a well coordinated and efficient regulative response to innate immune activation.

Chronic hepatitis C and persistent occult hepatitis C virus infection are characterized by distinct immune cell cytokine expression profiles

Hepatitis C virus (HCV) replicates in immune cells in both chronic hepatitis C (CHC) and occult HCV infection, but the extent of virus replication in this compartment in these opposing infection forms varies greatly. It was unknown whether this could be linked to HCV genotype or to differences in host gene expression shaping the immune response, and whether HCV replication in immune cells is sensitive to endogenous antiviral cytokines. In this study, we uncovered that significantly greater HCV load in peripheral blood mononuclear cells (PBMC), but not in plasma, coincided with HCV genotypes 2 and 3 in CHC, but with genotype 1 in residual occult infection after clinical resolution of hepatitis C. Moreover, PBMC from individuals with occult infection transcribed significantly greater levels of IFN-alpha, IFN-gamma and TNF-alpha, but less interleukin (IL)-10 than those from CHC. In CHC, PBMC with low HCV load expressed significantly more IFN-gamma but less IL-12 than did cells with high virus content. In occult infection, HCV RNA detection in PBMC was associated with much lower IFN-alpha and IL-12 expression. Further, HCV replication in T lymphocytes could be completely eliminated by activation of endogenous IFN-gamma in CHC, but of IFN-alpha in occult infection. In conclusion, CHC and persistent occult HCV infection are characterized by clearly different profiles of antiviral cytokine response in circulating immune cells which are also different from those of healthy individuals. Higher expression of IL-10, combined with lower transcription of IFN-alpha, IFN-gamma and TNF-alpha, is associated with a more robust HCV replication in immune cells.

333 Oral type 1 interferon protection from lethal influenza virus

The persistence of highly pathogenic avian influenza virus within wild bird populations has forged interest in control measures to limit a possible human pandemic. We have identified an optimal low oral dose of IFN- α that when delivered daily as prophylactic therapy protects C57BL/6J mice from a lethal challenge with mouse adapted human influenza virus A/PR/8/34 H1N1. These results provide strong support for the application of low dose type 1 IFN pretreatment to human influenza control. Additionally, recent data suggests that low dose oral IFN- αA treatment of influenza causes the recruitment of Regulatory T cells from the spleen to the site of inflammation; this response may form the basis of the observed protection from lethal infection.

Genetic factors predicting IFN‐gamma generation potential in patients with sarcoidosis and after haematopoietic stem cell transplantation

HLA B8, which is known to associate with a poor proliferative response, constitutes a risk factor of antinuclear antibodies formation in asbestos workers. B8 and DR3 are in a linkage disequilibrium with TNF*A2 allele which characterizes individuals as high TNF-alpha producers. Therefore, haplotype having B8, DR3, TNF*A2 characterizes individuals with rather low proliferative response of lymphocytes and low IFN-gamma generation potential. The above genetical features (B8, DR3 and TNF*A2), associated with a characteristic TNF alpha and IFN gamma generation profile, make sarcoidosis patients prone to develop Lofgren syndrome symptoms. Indeed, low IFN gamma producers genotype (3/3 homozygotes) and HLA DRB1*03 constitute risk factors of Lofgren syndrome in a combined fashion. In patients receiving hematopoietic stem cell transplantation, low IFN gamma producer genotype make people more susceptible to CMV and EBV reactivation as well as to acute and chronic GvHD. Therefore, genetical factors associated with the magnitude of immune response are of a value in predicting the natural history of some diseases thus helping in diagnosis and in tailoring of the treatment.