Interferon-λ3/4 genetic variants and interferon-λ3 serum levels are biomarkers of lupus nephritis and disease activity in Taiwanese

Uncoupling interferons and the interferon signature explains clinical and transcriptional subsets in SLE

Systemic lupus erythematosus (SLE) displays a hallmark interferon (IFN) signature. Yet, clinical trials targeting type I IFN (IFN-I) have shown variable efficacy, and blocking IFN-II failed to treat SLE. Here, we show that IFN type levels in SLE vary significantly across clinical and transcriptional endotypes. Whereas skin involvement correlated with IFN-I alone, systemic features like nephritis associated with co-elevation of IFN-I, IFN-II, and IFN-III, indicating additive IFN effects in severe SLE. Notably, while high IFN-II/-III levels without IFN-I had a limited effect on disease activity, IFN-II was linked to IFN-I-independent transcriptional profiles (e.g., OXPHOS and CD8+GZMH+ cells), and IFN-III enhanced IFN-induced gene expression when co-elevated with IFN-I. Moreover, dysregulated IFNs do not explain the IFN signature in 64% of patients or clinical manifestations including cytopenia, serositis, and anti-phospholipid syndrome, implying IFN-independent endotypes in SLE. This study sheds light on mechanisms underlying SLE heterogeneity and the variable response to IFN-targeted therapies in clinical trials.

Prognostic Role of Interferon-λ3 in Anti-Melanoma Differentiation-Associated Gene 5-Positive Dermatomyositis-Associated Interstitial Lung Disease

OBJECTIVE

Interferon-λ3 (IFNλ3) is a cytokine with antiviral functions on barrier surfaces, and it is associated with disease activity in autoimmune diseases. This study assessed the clinical significance of serum IFNλ3 levels in polymyositis/dermatomyositis (PM/DM)-associated interstitial lung disease (ILD).

METHODS

We measured serum IFNλ3 levels in 221 patients with PM/DM-ILD (155 in the derivation cohort, 66 in the validation cohort) and 38 controls. We evaluated factors associated with mortality risk among 79 patients with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive DM-ILD.

RESULTS

Serum IFNλ3 levels at diagnosis were significantly higher in patients with PM/DM-ILD than in healthy controls. Remarkably, serum IFNλ3 levels were specifically increased in patients with anti-MDA5 antibody-positive DM-ILD in both the derivation and validation cohorts. In anti-MDA5 antibody-positive DM-ILD, patients with high IFNλ3 levels (>120 pg/mL) had significantly lower survival rates than those with low IFNλ3 levels (≤120 pg/mL). A multivariate analysis revealed that high IFNλ3 levels, as well as old age and low Pao2, were significantly associated with poor prognoses in patients with anti-MDA5 antibody-positive DM-ILD. In a classification analysis of patients with anti-MDA5 antibody-positive DM-ILD based on age, IFNλ3 level, and Pao2, patients with old age (>53 years), high IFNλ3 levels (>120 pg/mL), and low Pao2 (<75 mm Hg) had the worst survival. In lung pathologic analyses, IFNλ3-positive staining was observed in macrophages, airway epithelial cells, the pleural region, and intrapulmonary veins in patients with anti-MDA5 antibody-positive DM-ILD.

CONCLUSION

Serum IFNλ3 is a promising biomarker for identifying patients at high risk of poor outcomes in anti-MDA5 antibody-positive DM-ILD.

Understanding the role of exosomal lncRNAs in rheumatic diseases: a review

Rheumatic diseases, a group of diseases whose etiology is still unclear, are thought to be related to genetic and environmental factors, leading to complex pathogenesis. Based on their multi-system involvement, the diagnosis and treatment continue to face huge challenges. Whole-genome assays provide a distinct direction for understanding the underlying mechanisms of such diseases. Exosomes, nano-sized bilayer membrane vesicles secreted by cells, are mentioned as a key element in the physiological and pathological processes of the body. These exosomes mediate biologically active substances, such as nucleic acids, proteins, and lipids and deliver them to cells. Notably, long non-coding RNAs (lncRNAs), a unique class of non-coding RNAs, have been implicated in the pathogenesis of rheumatic diseases. However, the mechanism needs to be further explored. This article provided a comprehensive review of the findings on exosomal lncRNAs in rheumatic diseases, including rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus, autoimmune liver diseases, primary dermatomyositis, and systemic sclerosis. Through in-depth understanding of these lncRNAs and their involved signaling pathways provide new theoretical supports for the diagnosis and treatment of rheumatic diseases.

Association between endothelin-1 and systemic lupus erythematosus: insights from a case-control study

Systemic lupus erythematosus (SLE) is a chronic rheumatic disorder. Endothelin-1, a vasoconstrictor, belongs to the endothelin family and is associated with vascular-related damages. To date, association between ET-1 and pathogenesis of SLE remains unclear. This case-control study was carried out by 314 SLE, 252 non-SLE diseases patients and 500 healthy controls. Serum ET-1, CCN3, IL-28B levels were detected by ELISA, and ET-1 gene polymorphisms (rs5369, rs5370, rs1476046, rs2070699, rs2071942, rs2071943, rs3087459, rs4145451, rs6458155, rs9369217) were genotyped with Kompetitive Allele-Specific PCR. SLE patients had high levels of ET-1, which were correlated with some clinical, laboratory features. Serum CCN3, IL-28B levels were higher in SLE patients, and ET-1 levels were positively correlated with the two cytokines. Rs5370, rs1476046, rs2070699, rs2071942, rs2071943, rs3087459, rs6458155 and rs2070699 were associated with SLE risk. Rs2070699 (T, TT) was related to SLE patients with alopecia. Rs5370 (T, TT, TG), rs1476046 (G,GA), rs2071942 (G,GA) and rs2071943 (G,GA) were associated with SLE patients with pericarditis, pyuria and fever manifestation, respectively. Rs3087459 (CC) and rs9369217 (TC) were related to SLE patients with positive anti-SSB antibody. Rs5369 (AA) was associated with IgG and CRP levels in SLE patients. In conclusion, elevated serum ET-1 in SLE patients may be a potential disease marker, and its gene polymorphisms were related to SLE susceptibility.

Uncoupling interferons and the interferon signature explain clinical and transcriptional subsets in SLE

Interferons (IFN) are thought to be key players in systemic lupus erythematosus (SLE). The unique and interactive roles of the different IFN families in SLE pathogenesis, however, remain poorly understood. Using reporter cells engineered to precisely quantify IFN-I, IFN-II and IFN-III activity levels in serum/plasma, we found that while IFNs play essential role in SLE pathogenesis and disease activity, they are only significant in specific subsets of patients. Interestingly, whereas IFN-I is the main IFN that governs disease activity in SLE, clinical subsets are defined by the co-elevation of IFN-II and IFN-III. Thus, increased IFN-I alone was only associated with cutaneous lupus. In contrast, systemic features, such as nephritis, were linked to co-elevation of IFN-I plus IFN-II and IFN-III, implying a synergistic effect of IFNs in severe SLE. Intriguingly, while increased IFN-I levels were strongly associated with IFN-induced gene expression (93.5%), in up to 64% of cases, the IFN signature was not associated with IFN-I. Importantly, neither IFN-II nor IFN-III explained IFN-induced gene expression in patients with normal IFN-I levels, and not every feature in SLE was associated with elevated IFNs, suggesting IFN-independent subsets in SLE. Together, the data suggest that, unlike the IFN signature, direct quantification of bioactive IFNs can identify pathogenic and clinically relevant SLE subsets amenable for precise anti-IFN therapies. Since IFN-I is only elevated in a subset of SLE patients expressing the IFN signature, this study explains the heterogeneous response in clinical trials targeting IFN-I, where patients were selected based on IFN-induced gene expression rather than IFN-I levels.

Association of Immune-Related Genetic and Epigenetic Alterations with Lupus Nephritis

BACKGROUND

The familial clustering phenomenon together with environmental influences indicates the presence of a genetic and epigenetic predisposition to systematic lupus erythematosus (SLE). Interestingly, regarding lupus nephritis (LN), the worst complication of SLE, mortality, and morbidity were not consistent with SLE in relation to sexuality and ethnicity.

SUMMARY

Genetic and epigenetic alterations in LN include genes and noncoding RNAs that are involved in antigen-presenting, complements, immune cell infiltration, interferon pathways, and so on. Once genetic or epigenetic change occurs alone or simultaneously, they will promote the formation of immune complexes with autoantibodies that target various autoantigens, which results in inflammatory cytokines and autoreactive immune cells colonizing renal tissues and contributing to LN.

KEY MESSAGES

Making additional checks for immunopathology-related heredity and epigenetic factors may lead to a more holistic perspective of LN.

Association between Psoriasis Disease and IFN-λ Gene Polymorphisms

Psoriasis is one of the most common chronic immune-mediated skin diseases, having a strong genetic predisposition. Psoriasis is a T-cell-mediated disease with a mixed Th1/Th17 cytokines environment. IL-23/IL-17 axis hyperactivation is the primary pathogenesis. Psoriasis lesions have been known to exhibit high IFN-λ1 and IFN-stimulated genes (ISGs) expression, which appears to be driven by Th17 cells. However, the role and mechanism of IFN-λs in psoriasis disease remains unknown. The study aimed to investigate the relationship between IL-28B and IL-29 gene polymorphisms with psoriasis disease and clinical severity. We performed single-nucleotide polymorphisms (SNPs) of IL-28B rs12979860 (IL-28 C/T), rs8099917 (IL-28 T/G), and IL-29 rs30461 (IL-29 T/C) in 140 patients with psoriasis disease and 159 healthy controls using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The genotype and allele frequency distributions of the rs12979860 (IL-28 C/T) and rs30461 (IL-29 T/C) polymorphisms were similar in the patient and control groups and were not statistically significant. The TG genotype of rs8099917 was statistically significantly different in patients from both groups. The TG genotype increased the risk of disease1.9-fold. The G allele may be associated with the pathogenesis of psoriasis.

B Cell Activation and Plasma Cell Differentiation Are Promoted by IFN-λ in Systemic Lupus Erythematosus

Type I IFN is essential for viral clearance but also contributes to the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus (SLE), via aberrant nucleic acid-sensing pathways, leading to autoantibody production. Type III IFN (IFN-λ) is now appreciated to have a nonredundant role in viral infection, but few studies have addressed the effects of IFN-λ on immune cells given the more restricted expression of its receptor primarily to the epithelium. In this study, we demonstrate that B cells display a prominent IFN gene expression profile in patients with lupus. Serum levels of IFN-λ are elevated in SLE and positively correlate with B cell subsets associated with autoimmune plasma cell development, including CD11c+T-bet+CD21- B cells. Although B cell subsets express all IFN receptors, IFNLR1 strongly correlates with the CD11c+CD21- B cell expansion, suggesting that IFN-λ may be an unappreciated driver of the SLE IFN signature and B cell abnormalities. We show that IFN-λ potentiates gene transcription in human B cells typically attributed to type I IFN as well as expansion of T-bet-expressing B cells after BCR and TLR7/8 stimulation. Further, IFN-λ promotes TLR7/8-mediated plasmablast differentiation and increased IgM production. CD11c+ B cells demonstrate IFN-λ hyperresponsive signaling compared with other B cell subsets, suggesting that IFN-λ accelerates plasma cell differentiation through this putative extrafollicular pathway. In summary, our data support type III IFN-λ as a cytokine promoting the Ab-secreting cell pool in human viral and autoimmune disease.

Type III Interferons: Emerging Roles in Autoimmunity

Type III interferons (IFNs) or the lambda IFNs (IFNLs or IFN-λs) are antimicrobial cytokines that play key roles in immune host defense at endothelial and epithelial barriers. IFNLs signal via their heterodimeric receptor, comprised of two subunits, IFNLR1 and interleukin (IL)10Rβ, which defines the cellular specificity of the responses to the cytokines. Recent studies show that IFNL signaling regulates CD4+ T cell differentiation, favoring Th1 cells, which has led to the identification of IFNL as a putative therapeutic target for autoimmune diseases. Here, we summarize the IFNL signaling pathways during antimicrobial immunity, IFNL-mediated immunomodulation of both innate and adaptive immune cells, and induction of autoimmunity.

Interferon Lambda Regulates Cellular and Humoral Immunity in Pristane-Induced Lupus

A pivotal role of type I interferons in systemic lupus erythematosus (SLE) is widely accepted. Type III interferons (IFN-λ) however, the most recently discovered cytokines grouped within the interferon family, have not been extensively studied in lupus disease models yet. Growing evidence suggests a role for IFN-λ in regulating both innate and adaptive immune responses, and increased serum concentrations have been described in multiple autoimmune diseases including SLE. Using the pristane-induced lupus model, we found that mice with defective IFN-λ receptors (Ifnlr1^−/−) showed increased survival rates, decreased lipogranuloma formation and reduced anti-dsDNA autoantibody titers in the early phase of autoimmunity development compared to pristane-treated wild-type mice. Moreover, Ifnlr1^−/− mice treated with pristane had reduced numbers of inflammatory mononuclear phagocytes and cNK cells in their kidneys, resembling untreated control mice. Systemically, circulating B cells and monocytes (CD115⁺Ly6C⁺) were reduced in pristane-treated Ifnlr1^−/− mice. The present study supports a significant role for type III interferons in the pathogenesis of pristane-induced murine autoimmunity as well as in systemic and renal inflammation. Although the absence of type III interferon receptors does not completely prevent the development of autoantibodies, type III interferon signaling accelerates the development of autoimmunity and promotes a pro-inflammatory environment in autoimmune-prone hosts.

Cytokines as Biomarkers in Systemic Lupus Erythematosus: Value for Diagnosis and Drug Therapy

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease. The disease is characterized by activation and dysregulation of both the innate and the adaptive immune systems. The autoimmune response targets self-molecules including cell nuclei, double stranded DNA and other intra and extracellular structures. Multiple susceptibility genes within the immune system have been identified, as well as disturbances in different immune pathways. SLE may affect different organs and organ systems, and organ involvement is diverse among individuals. A universal understanding of pathophysiological mechanism of the disease, as well as directed therapies, are still missing. Cytokines are immunomodulating molecules produced by cells of the immune system. Interferons (IFNs) are a broad group of cytokines, primarily produced by the innate immune system. The IFN system has been observed to be dysregulated in SLE, and therefore IFNs have been extensively studied with a hope to understand the disease mechanisms and identify novel targeted therapies. In several autoimmune diseases identification and subsequent blockade of specific cytokines has led to successful therapies, for example tumor necrosis factor-alpha (TNF-α) inhibition in rheumatoid arthritis. Authors of this review have sought corresponding developments in SLE. In the current review, we cover the actual knowledge on IFNs and other studied cytokines as biomarkers and treatment targets in SLE.

Regulation of B Cell Responses in SLE by Three Classes of Interferons

There are three classes of interferons (type 1, 2, and 3) that can contribute to the development and maintenance of various autoimmune diseases, including systemic lupus erythematosus (SLE). Each class of interferons promotes the generation of autoreactive B cells and SLE-associated autoantibodies by distinct signaling mechanisms. SLE patients treated with various type 1 interferon-blocking biologics have diverse outcomes, suggesting that additional environmental and genetic factors may dictate how these cytokines contribute to the development of autoreactive B cells and SLE. Understanding how each class of interferons controls B cell responses in SLE is necessary for developing optimized B cell- and interferon-targeted therapeutics. In this review, we will discuss how each class of interferons differentially promotes the loss of peripheral B cell tolerance and leads to the development of autoreactive B cells, autoantibodies, and SLE.

Monocytes differentiated into macrophages and dendritic cells in the presence of human IFN-λ3 or IFN-λ4 show distinct phenotypes

Human IFN-λ4 is expressed by only a subset of individuals who possess the ΔG variant allele at the dinucleotide polymorphism rs368234815. Recent genetic studies have shown an association between rs368234815 and different infectious and inflammatory disorders. It is not known if IFN-λ4 has immunomodulatory activity. The expression of another type III IFN, IFN-λ3, is also controlled by genetic polymorphisms that are strongly linked to rs368234815. Therefore, it is of interest to compare these two IFNs for their effects on immune cells. Herein, using THP-1 cells, it was confirmed that IFN-λ4 could affect the differentiation status of macrophage-like cells and dendritic cells (DCs). The global gene expression changes induced by IFN-λ4 were also characterized in in vitro generated primary macrophages. Next, human PBMC-derived CD14+ monocytes were used to obtain M1 and M2 macrophages and DCs in the presence of IFN-λ3 or IFN-λ4. These DCs were cocultured with CD4+ Th cells derived from allogenic donors and their in vitro cytokine responses were measured. The specific activity of recombinant IFN-λ4 was much lower than that of IFN-λ3, as shown by induction of IFN-stimulated genes. M1 macrophages differentiated in the presence of IFN-λ4 showed higher IL-10 secretion than those differentiated in IFN-λ3. Coculture experiments suggested that IFN-λ4 could confer a Th2-biased phenotype to allogenic Th cells, wherein IFN-λ3, under similar circumstances, did not induce a significant bias toward either a Th1 or Th2 phenotype. This study shows for the first time that IFN-λ4 may influence immune responses by immunomodulation.

Presence of interferon-λ 4, male gender, absent/mild steatosis and low viral load augment antibody levels to hepatitis C virus

OBJECTIVES

Despite recombinant interferon-λ 4 (IFN-λ4) demonstrating anti-viral activity in vitro and the ancestral functional gene (IFNL4) being conserved in all other primates, there has been speculation that IFN-λ4 may be detrimental in humans. In light of recent rekindled interest in humoral immunity, this study aimed at evaluating the impact of baseline characteristics, including IFNL4, on antibody levels to hepatitis C virus (HCV).

MATERIALS AND METHODS

Pretreatment sera from 279 well-characterized North European Caucasians with chronic HCV genotype 2 or 3 infection having undergone liver biopsy were analyzed regarding IFNL4 (rs12979860) and anti-HCV antibody levels using a commercially available assay.

RESULTS

Patients producing IFN-λ4 had higher signal to cut-off (S/CO) anti-HCV antibody ratios as compared with those lacking IFN-λ4 (IFNL4_rs12979860 CT/TT versus CC, p<.0001, Mann-Whitney U-test). Additionally, in univariate analyses S/CO was significantly higher in men than women (p<.001), as well as in patients with absent/mild interface hepatitis (Ishak grade 0-2 versus 3-4, p = .009), and absent/mild steatosis (grade 0-1 versus 2-3, p = .0005). Also, an inverse correlation with HCV RNA level (r_s= -0.14, p = .02) was noted. In multivariate analysis IFN-λ4, gender, steatosis and viral load remained independently associated.

CONCLUSIONS

To our knowledge, this is the first report that demonstrates that the ability to produce IFN-λ4, in addition to male gender, absent/mild steatosis, and lower viral load, augments antibody levels against HCV. This indicates that IFN-λ4 may be associated with T helper cell 2 (Th2) immune skewing, which might have clinical implications beyond HCV infection. ClinicalTrials.gov Identifier: NCT00143000.

Interferon Lambda 3/4 (IFNλ3/4) rs12979860 Polymorphisms Is Not Associated With Susceptibility to Systemic Lupus Erythematosus, Although It Regulates OASL Expression in Patients With SLE

Systemic lupus erythematosus (SLE) is an autoimmune disease with a complex etiology. Various genetic factors are associated with susceptibility to developing SLE and contribute to its onset and progression. Different single-nucleotide polymorphisms (SNPs) have been associated with SLE in several populations. The rs12979860 SNP in interferon lambda 3/4 (IFNλ3/4) is significantly associated with SLE susceptibility in patients negative for nephritis in Taiwanese people, and interferon-stimulated genes (ISGs) are differentially expressed in normal liver by the rs12979860 genotype. This study aimed to investigate whether rs12979860 is associated with the presence of SLE and lupus nephritis in Mexican individuals as well as with the expression of several ISGs in SLE patients. In total, 439 SLE patients and 358 healthy donors were genotyped for rs12979860 using real-time PCR, and allelic discrimination plots were constructed. Additionally, peripheral blood mononuclear cells (PBMCs) were isolated from the venous blood of SLE patients by centrifugation (n = 78). The mRNA levels of 2′-5′-oligoadenylate synthetase like (OASL), myxovirus resistance 1 (MX1), 2′5′-oligoadenylate synthetase 1 (OAS1), interferon-stimulated gene 15 (ISG15) and lymphocyte antigen 6 complex, locus E (LY6E) were determined using real-time PCR. The distributions of rs12979860 genotypes and allele frequencies were compared between SLE patients and healthy donors; case-control analysis revealed that rs12979860 was not associated with SLE susceptibility (OR 1.18, 95% CI 0.97–1.45, p = 0.08) or with the risk for lupus nephritis (OR 0.913, 95% CI 0.590–1.411, p = 0.682). However, OASL expression levels in PBMCs were significantly different between rs12979860 genotypes in SLE patients: median OASL mRNA levels were significantly higher in patients carrying the CC genotype (197.10, IQR 71.10–411.17) than in those with CT/TT genotypes (173.75, IQR 58.80–278.75, p = 0.016). Our results suggest that the SNP rs12979860 does not play a relevant role in susceptibility to SLE in Mexican individuals. However, IFNλ3/4 genotypes appear to be associated with OASL expression in PBMCs from patients with SLE.

Interferon lambda in inflammation and autoimmune rheumatic diseases

Interferons are potent antiviral cytokines that modulate immunity in response to infection or other danger signals. In addition to their antiviral functions, type I interferons (IFNα and IFNβ) are important in the pathogenesis of autoimmune diseases. Type III interferons (IFNλs) were initially described as a specialized system that inhibits viral replication at epithelial barrier surfaces while limiting inflammatory damage. However, evidence now suggests that type III interferons have complex effects on both innate and adaptive immune responses and might also be pathogenic in systemic autoimmune diseases. Concentrations of IFNλs are increased in blood and tissues in a number of autoimmune rheumatic diseases, including systemic lupus erythematosus, and are further associated with specific clinical and laboratory parameters. This Review is aimed at providing a critical evaluation of the current literature on IFNλ biology and how type III interferons might contribute to immune dysregulation and tissue damage in autoimmunity. The potential effects of type III interferons on treatment strategies for autoimmune rheumatic diseases, such as interferon blockade, are also considered.

Interferon lambda 4 genotype and pathway in alcoholic hepatitis

OBJECTIVES

Single nucleotide polymorphisms within the interferon lambda 4 (IFNL4) gene influence liver inflammation and fibrosis in chronic liver disease. We investigated whether this is also the case during acute liver disease, alcoholic hepatitis. We, therefore, related variants within the IFNL4 gene to the clinical course of acute alcoholic hepatitis, and characterized the activation state of the IFN lambda system in these patients.

METHODS

In this pilot study, 58 patients with alcoholic hepatitis were genotyped for the rs368234815IFNL4 single nucleotide polymorphism (deltaG, deltaG/TT: IFN lambda 4 positive, TT/TT: IFN lambda 4 negative). The genotypes were related to mortality, infection and inflammation and expression of the IFNL receptor 1 and IFN inducible genes were measured in liver and peripheral leukocytes.

RESULTS

Amongst the alcoholic hepatitis patients who died, the IFN negative patients live longer after diagnosis, and also the IFN negative patients tended to have an overall short-term survival benefit compared to IFN lambda positive patients (p = .058). The IFN lambda 4 negative patients at diagnosis had fewer circulating monocytes and lower plasma soluble CD163. The patients with alcoholic hepatitis had reduced expression of the IFNL receptor 1in both liver and blood compared with healthy controls. In blood, the expression of IFN stimulated genes was lower than in healthy controls and most so in the patients, who died.

CONCLUSIONS

The IFN lambda 4 pathway seems involved in the acute disease processes of alcoholic hepatitis and patients without IFN lambda expression seem to have a short-term survival benefit.

The regulation and pharmacological modulation of immune complex induced type III IFN production by plasmacytoid dendritic cells

OBJECTIVE

Patients with systemic lupus erythematosus (SLE) have an ongoing interferon (IFN) production due to an activation of plasmacytoid dendritic cells (pDCs), which can be triggered to type I IFN synthesis by RNA containing immune complexes (RNA-IC). Considering emerging data suggesting a role of type III IFN in the SLE disease process, we asked if RNA-IC can induce type III IFN production in pDC and how this production can be regulated.

METHODS

Peripheral blood mononuclear cells (PBMCs) or immune cell subsets were isolated from healthy blood donors or SLE patients and stimulated with IC containing U1 snRNP and SLE-IgG (RNA-IC). Hydroxychloroquine (HCQ) and an interleukin receptor 1-associated kinase 4 inhibitor (IRAK4i) were added to cell cultures. Cytokine mRNA levels were determined with a microarray and protein levels with immunoassays. Single-cell RNA sequencing of pDCs using ddSEQ technology was performed.

RESULTS

Type III IFN mRNA and protein was induced in RNA-IC-stimulated pDC-NK and pDC-B cell co-cultures. A subset of activated pDCs (3%) expressed both type III and type I IFN mRNA. IFN-λ2, IFN-α2b, interleukin (IL)-3, IL-6, or granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced IFN-λ1/3 production 2-5-fold. HCQ and an IRAK4i blocked the RNA-IC-triggered IFN-λ1/3 production (p < 0.01). IFN-α2b and GM-CSF increased the proportion of SLE patients producing IFN-λ1/3 in response to RNA-IC from 11 to 33%.

CONCLUSIONS

Type III IFN production is triggered by RNA-IC in pDCs in a TLR-MyD88-dependent manner, enhanced by NK and B cells as well as several pro-inflammatory cytokines. These results support a contributing role for both type I and type III IFNs in SLE, which needs to be considered when targeting the IFN system in this disease.

The presence of IFL3/4 rs12979860 C allele influences the in vitro IP-10 production by mononuclear cells from patients with systemic lupus erythematosus

OBJECTIVE

To explore whether the IFNL3/4 rs12979860 genotype may influence serum levels or production of interferon-inducible protein-10 (IP-10) by peripheral blood mononuclear cells from patients with systemic lupus erythematosus (SLE).

METHODS

Sixty-six patients with SLE and 22 healthy blood donors (controls) were included. The IFNL3/4 rs12979860 polymorphism was genotyped by real-time polymerase chain reaction. IP-10 levels in sera supernatants of IFNα stimulated peripheral blood mononuclear cells were measured by enzime-linked immunosorbent assay.

RESULTS

Allelic frequencies were CC (29%), CT (52%) and TT (20%) in SLE, and CC (32%), CT (41%) and TT (27%) in healthy controls. Median serum IP-10 levels were higher in SLE patients than in controls (190.8 versus 118.1 pg/ml; p < 0.001), particularly in those with high disease activity (278.5 versus 177.2 pg/ml; p = 0.037). However, serum IP-10 levels were not influenced by IFNL3/4 genotypes. Higher IP-10 production by peripheral blood mononuclear cells was found in both SLE patients (median 519.3 versus 207.6 pg/ml; p = 0.012) and controls (median 454.0 versus 201.7 pg/ml; p = 0.034) carrying the IFNL3/4 C allele compared with carriers of the T allele.

CONCLUSIONS

Although IFNL3/4 rs12979860 allele C does not appear to influence serum IP-10 levels in SLE, it plays an important role in the production of IP-10 by peripheral blood mononuclear cells after IFNα stimulation.

Interferon lambda promotes immune dysregulation and tissue inflammation in TLR7-induced lupus

Type III IFN lambdas (IFN-λ) have recently been described as important mediators of immune responses at barrier surfaces. However, their role in autoimmune diseases such as systemic lupus erythematosus (SLE), a condition characterized by aberrant type I IFN signaling, has not been determined. Here, we identify a nonredundant role for IFN-λ in immune dysregulation and tissue inflammation in a model of TLR7-induced lupus. IFN-λ protein is increased in murine lupus and IFN-λ receptor (Ifnlr1) deficiency significantly reduces immune cell activation and associated organ damage in the skin and kidneys without effects on autoantibody production. Single-cell RNA sequencing in mouse spleen and human peripheral blood revealed that only mouse neutrophils and human B cells are directly responsive to this cytokine. Rather, IFN-λ activates keratinocytes and mesangial cells to produce chemokines that induce immune cell recruitment and promote tissue inflammation. These data provide insights into the immunobiology of SLE and identify type III IFNs as important factors for tissue-specific pathology in this disease.

Type III Interferons (Lambda Interferons) in Rheumatic Autoimmune Diseases

The last 2 decades have witnessed the discovery and characterization of a new family of cytokines with immunological characteristics similar to those described for type I interferons, type III or lambda interferons. Unraveling the molecular mechanisms underlying each type of interferon has allowed us to understand how some autoimmune diseases can be considered as interferonopathies. Under normal conditions, type III interferons play a key role in the defense against viruses by modulating the functioning of several types of innate and adaptive immune cells. These effects include upregulation of major histocompatibility complex molecules by myeloid dendritic cells, increased functioning of pattern recognition receptors by plasmacytoid dendritic cells, decreased activity of regulatory T cells, enhanced production of antibodies by plasmatic cells and increased expression of chemokines and adhesion molecules by leukocytes and endothelial cells. Notably, all these mechanisms have been described to boost autoimmunity, and type III interferons pathway activation has been related to the pathogenesis of autoimmune conditions such as systemic lupus erythematosus, systemic sclerosis and Sjögren's syndrome. This review provides an overview of the current evidence on the contribution of type III interferons in the pathogenesis of rheumatic autoimmune diseases in humans.

Independent association of low IFNλ1 gene expression and type I IFN score/IFNλ1 ratio with obstetric manifestations and triple antiphospholipid antibody positivity in primary antiphospholipid syndrome

Recent data suggest an important role of type I interferons (IFN) in antiphospholipid syndrome (APS). Here we aimed to evaluate the interplay of type I and type III (or IFNλs) IFNs in APS and potential clinical and serological associations. Our findings suggest that patients with primary APS (PAPS) and systemic lupus erythematosus (SLE)/APS displayed increased type I IFN scores but decreased IFNλ1 gene expression levels compared to healthy individuals, as assessed with real-time qPCR analysis in isolated peripheral blood mononuclear cells (PBMCs). Type I IFN score/IFNλ1 ratio was remarkably higher in patients with PAPS and SLE/APS as well as in SLE patients with or without antiphospholipid antibodies (aPL) vs controls. In conclusion, our results reveal an association between low IFNλ1 expression and obstetric APS. Moreover, the type I IFN score/IFNλ1 ratio seems to be a potential marker of high risk APS given its associations with triple aPL positivity.

Interferons (IFN-A/-B/-G) Genetic Variants in Patients with Mixed Connective Tissue Disease (MCTD)

Mixed connective tissue disease (MCTD) is a rare complex autoimmune disease in which autoantigens are recognized by endosomal TLRs. Their activation induces a higher secretion of the type I interferons, IFN-γ and the up-regulation of the INF-inducible genes. The present study aimed to investigate whether SNPs that are located in the IFN-A, IFN-B, and IFN-G genes are associated with MCTD. 145 MCTD patients and 281 healthy subjects were examined for IFN-A, IFN-B, and IFN-G genetic variants by TaqMan SNP genotyping assay. ELISA determined IFN-α/-β/-γ serum levels. Among the seven tested SNPs, four polymorphisms: IFN-A rs10757212, IFN-A rs3758236, IFN-G rs2069705, IFN-G rs2069718, as well as INF-G rs1861493A/rs2069705A/rs2069718G haplotype were significantly associated with a predisposition for MCTD. Raynaud's phenomenon, erosive arthritis, swollen hands and fingers, and sclerodactyly were significantly more frequently observed in MCTD patients with IFN-G rs2069718 G allele than in patients with IFN-G rs2069718 A allele. We also found that anti-U1-A autoantibodies most frequently occurred in MCTD patients with rs2069718 GA genotype, while the IFN-G rs2069705 AG and rs2069718 GA genotypes might be a marker of anti-Ro60 presence in MCTD patients. Our results indicate that IFN-G genetic variants may be potential genetic biomarkers for MCTD susceptibility and severity.

Potential protein biomarkers for systemic lupus erythematosus determined by bioinformatics analysis

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disorder, and its pathogenesis in males and in cases without accompanying lupus nephritis (LN^-) is not fully understood. In this study, we identified 90 (82 up- and 8 downregulated) differentially expressed genes (DEGs) common to female LN^-, female LN⁺ and male LN⁺ using the GSE65391 and GSE49454 gene expression datasets from Gene Expression Omnibus database (GEO). The protein-protein interaction (PPI) network of 70 DEGs was constructed using STRING and cytoscape, and the Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the PPI network was significantly enriched in defense response to virus, cytosol, protein binding and measles. Sixteen hubgenes were identified from this PPI network, and Literature Mining Gene Networks molecular of GenCLiP 2.0 showed strong interaction between STAT1, DDX58 and IFIT1. Enrichment analysis of hubgenes in published literature showed the involvement of immune response and interferon-related genes in the pathogenesis of SLE. In addition, the transcription factors STAT1 & 2 and IRF6 & 9 had high Normalized Enrichment Score (NES). The 70 DEGs with PPI network and 16 hubgenes are potential biomarkers of SLE, and can help improve diagnosis and develop individualized therapies.

Interferon Lambda and Liver Fibrosis

Fibrosis is a highly conserved and coordinated wound healing response to injury. In the liver, injury is promoted by immune effector mechanisms that are common across various disease etiologies and even between organs such as lungs, kidneys, heart, and other organs. Thus, the liver represents a useful model to study inflammation and repair, particularly as it is frequently biopsied in clinical contexts. Currently, strong evidence implicates IFNL3/4 polymorphisms and interferon (IFN)-λ3 levels as determinants of the extent of hepatic inflammation and fibrosis in viral and nonviral liver diseases, as well as in governing the severity of nonhepatotropic viral diseases. Interestingly, IFNL3/4 polymorphisms and IFN-λ3 levels correlate with fibrosis extent in other organs such as the lung and kidney. In this review, we discuss the association between IFN-λ and tissue inflammation and fibrosis in human disease and the potential clinical utility of the findings.

Signaling Pathways of Type I and Type III Interferons and Targeted Therapies in Systemic Lupus Erythematosus

Type I and type III interferons (IFNs) share several properties in common, including the induction of signaling pathways, the activation of gene transcripts, and immune responses, against viral infection. Recent advances in the understanding of the molecular basis of innate and adaptive immunity have led to the re-examination of the role of these IFNs in autoimmune diseases. To date, a variety of IFN-regulated genes, termed IFN signature genes, have been identified. The expressions of these genes significantly increase in systemic lupus erythematosus (SLE), highlighting the role of type I and type III IFNs in the pathogenesis of SLE. In this review, we first discussed the signaling pathways and the immunoregulatory roles of type I and type III IFNs. Next, we discussed the roles of these IFNs in the pathogenesis of autoimmune diseases, including SLE. In SLE, IFN-stimulated genes induced by IFN signaling contribute to a positive feedback loop of autoimmunity, resulting in perpetual autoimmune inflammation. Based on this, we discussed the use of several specific IFN blocking strategies using anti-IFN-α antibodies, anti-IFN-α receptor antibodies, and IFN-α-kinoid or downstream small molecules, which intervene in Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathways, in clinical trials for SLE patients. Hopefully, the development of novel regimens targeting IFN signaling pathways will shed light on promising future therapeutic applications for SLE patients.

MicroRNA-145 Involves in the Pathogenesis of Renal Vascular Lesions and May Become a Potential Therapeutic Target in Patients with Juvenile Lupus Nephritis

AIMS

The current study was conducted with the central objective of investigating the expression of microRNA-145 (miR-145) in renal vascular lesions (RVLs) in juvenile lupus nephritis (JLN) and its possible mechanism.

METHODS

The clinical data of 49 JLN patients confirmed by renal biopsy were collected and followed by grouping according to the RVLs score after hematoxylin-eosin staining: mild, moderate, and severe groups. In situ hybridization was used to detect the expression of miR-145 in renal vessels which was then being compared among different RVLs groups. Up-LV-miR-145 and LV-miR-NC lentiviral vectors were constructed and transfected into human vascular smooth muscle cells (HVSMCs), respectively. After HVSMCs were treated with 10.0 µg/L platelet-derived growth factor (PDGF)-BB for 24 h, the proliferation, migration, and apoptosis of endothelial cells were detected by MTT, Transwell assay, and flow cytometry, respectively. Western blot was used to detect expression of alpha-smooth muscle actin (α-SM-actin) and osteopontin (OPN).

RESULTS

The expression of miR-145 in renal vascular cells was statistically significant. The higher the inner membrane ratio, the lesser the miR-145 expression. After treatment with PDGF-BB, expression of miR-145 in HVSMCs decreased, proliferation and migration ability enhanced, apoptosis decreased, α-SM-actin decreased, and OPN increased. The proliferation and migration ability of HVSMCs in the LV-miR-145 group suppressed, apoptosis enhanced, α-SM-actin increased, and OPN decreased.

CONCLUSIONS

Our study revealed that miR-145 expression decreased with the increase of vascular damage. miR-145 can inhibit proliferation, migration, and differentiation phenotypic transformation of HVSMCs induced by PDGF-BB. miR-145 may be involved in the pathogenesis of RVLs and may be a new target for treatment of RVLs in lupus nephritis.

The Genetic Association of IFN-λs with Human Inflammatory Disorders Remains a Conundrum

Type III Interferons (IFNs) or lambda IFNs (IFN-λs or IFNLs) although are primarily antiviral cytokines, may have roles to play in shaping immune responses, including those during inflammation. Genetic variants within the IFNL locus have been shown to be associated with various inflammatory conditions in humans ranging from metabolic to autoimmune and allergic diseases. The mechanism behind these genetic associations is not clear. Appropriate data analysis methods and functional evidence should be complimentarily used to identify the causal variants and mechanisms.