Varicella-zoster virus (VZV) is a neurotropic herpesvirus responsible for varicella and herpes zoster. Beyond its classical clinical manifestations, recent evidence shows that VZV reactivation may contribute to acute cardiovascular events. Vaccination reduces the incidence of herpes zoster and may confer cardiovascular benefits, although causality remains unproven. To summarise current evidence linking VZV infection to cardiovascular risk, evaluate the impact of VZV vaccination in the general and immune-mediated inflammatory disease (IMID) populations, and discuss the hypothesis that increased VZV reactivation under Janus kinase inhibitor (JAKi) therapy may partially explain the major adverse cardiovascular event (MACE) signal observed in the ORAL Surveillance trial. Epidemiologic studies show a consistent association between herpes zoster and a transient increase in MACEs. Mechanistic insights support VZV's ability to infect vascular tissues, induce inflammation, destabilise atherosclerotic plaques, and enhance thrombogenicity. Vaccination with the recombinant zoster vaccine (RZV) effectively prevents herpes zoster and is associated with reduced MACEs in large observational cohorts, although randomised trials powered for cardiovascular endpoints are lacking. In IMID populations, vaccination reduces herpes zoster incidence but has not consistently demonstrated cardiovascular benefit. JAKis, which increase VZV reactivation risk by impairing antiviral immunity, may create episodic vascular insults that contribute to the elevated MACE rates observed with tofacitinib in the ORAL Surveillance trial. VZV reactivation is a plausible and potentially preventable contributor to cardiovascular risk, particularly in older and immunosuppressed individuals. While vaccination shows promise in reducing zoster-associated cardiovascular risk, definitive causal evidence remains lacking. The hypothesised JAKi-VZV-vascular pathway warrants prospective evaluation.

Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) comprise a direct membrane-to-nucleus intracellular signaling pathway, facilitating rapid transcriptional changes in response to cytokines, growth factors, and hormones. Since the first JAK inhibitor (JAKi) gained regulatory approval in 2011, targeting of the JAK-STAT pathway has expanded significantly, with over a dozen approved agents and new indications in many immune-mediated inflammatory diseases. Newer agents targeting the JAK-STAT pathway have been developed with improved JAK selectivity, delivery to specific tissues, and new mechanisms of action in an effort to improve efficacy and address ongoing safety concerns. This review covers the expanding clinical use of JAK-STAT inhibition across immune-mediated inflammatory diseases as well as new therapeutic strategies and approaches.

OBJECTIVE:To evaluate the relationship across type I interferon (IFN-I)-stimulated gene (ISG) expression, Still disease, and the development of lung disease (LD) and drug-associated immune reactions (DAIR) to interleukin-1 (IL-1) and/or IL-6 inhibitors. METHODS:Whole blood ISG expression was quantified by NanoString array. ISG-28 scores were calculated in consecutive patients with Still or Still-like disease. Exome sequencing with family-based variant prioritization identified candidate genes harboring rare candidate causative variants. Lists of candidate genes were subjected to functional enrichment analysis. RESULTS:Among 57 patients (32 children, 25 adults), 16 had elevated ISG-28 scores. This group exhibited higher prevalence of LD (0.44 vs 0.1, P = 0.007) and DAIR (0.63 vs 0.17, P = 0.003) and lower IL-6 inhibitor use (0 vs 0.25, P = 0.048) compared to others. No significant differences were found in the rates of macrophage activation syndrome, active disease, elevated IL-18, or current IL-1 inhibition. The combination of HLA-DRB1*15 with high ISG-28 scores is associated with LD and DAIR with high specificity, whereas absence of both biomarkers had high negative predictive value. Candidate genes from high ISG-28 individuals were enriched in IFN-related pathways, including autophagy, IFN-I production, toll-like receptor signaling, macrophage activation, cytoskeletal organization, and responses to stress. CONCLUSION:High IFN-I expression correlates with LD and DAIR in Still disease, linked to rare genetic variation in immune pathways. Combining high ISG-28 with HLA-DRB1*15 significantly improves post hoc stratification of patients for these complications. If prospectively validated, these findings may guide molecular risk assessment and targeted therapies, including IFN-I directed treatments in Still disease with IFN-I signature.

Purpose:Type I interferonopathies are Mendelian inborn errors of immunity caused by defective clearance or recognition of nucleic acids, resulting in chronic type I interferon (IFN) activation. DNase II is a lysosomal endonuclease critical for degrading DNA during erythropoiesis and apoptosis. Biallelic loss-of-function variants in DNASE2 cause a rare autoinflammatory disorder. We aimed to characterize the clinical, genetic, and functional impact of a novel DNASE2 splice site variant in two unrelated patients. Methods:We performed exome and RNA sequencing to identify and validate variants. A minigene assay assessed splicing effects. DNase II activity was tested in cell lysates. Structural modeling, cytokine profiling, and immune stimulation assays were conducted to evaluate pathway activation and therapeutic response. Results:Both patients carried a homozygous DNASE2 splice site variant (c.511+5G>A), resulting in exon 4 skipping and impaired DNase II activity. They presented at birth with rash, thrombocytopenia, and anemia, later developing neutropenia, arthritis, failure to thrive, and systemic inflammation. One patient also harbored a homozygous USP43 variant that reduced USP43 expression and enhanced IFN signaling. Both patients showed increased JAK-STAT activation and responded clinically to JAK1/2 inhibition with ruxolitinib. Conclusion:We report a novel proximal intronic splice variant in DNASE2 associated with DNase II deficiency and type I interferon-mediated autoinflammation. Our findings expand the genotypic and phenotypic spectrum of this disorder, highlight the role of intronic variants in rare immune diseases, and support JAK inhibition as a targeted treatment approach.

Sarcopenia, the age-related decline in muscle mass, strength and function, is characterized by impaired muscle homeostasis, reduced regenerative potential of muscle stem cells (MuSCs) and increased fibrosis. Here we report that aged MuSCs can autonomously instruct fibro-adipogenic progenitors (FAPs) to proliferate and acquire a fibrogenic phenotype, independent of other cell types. Both the polycomb-deficient Ezh2−/− mouse model and aged mice exhibited defective regeneration, FAP expansion, fibrosis and elevated secretion of interleukin 6 (IL-6) and secreted phosphoprotein 1 (Spp1; osteopontin) by MuSCs. In aged MuSCs, reduction of the histone H3K27me3 repressive mark at the Nfbk1 gene correlated with its increased expression and enhanced chromatin recruitment to the IL6 and Spp1 genes, leading to their activation. Pharmacological inhibition of IL-6 and Spp1 signaling in co-culture systems or in aged mice reduced FAP proliferation and muscle fibrosis. These findings indicate that epigenetic dysregulation of aged MuSCs contributes to aged-related muscle fibrosis. Riparini et al. demonstrate that aged muscle stem cells amplify fibrosis by expanding mesenchymal progenitors via IL-6 and Spp1. Blocking these signals in aged mice curbs fibrosis and enhances muscle repair.

The mevalonate kinase (MVK) pathway is an essential metabolic pathway for sterol and isoprenoid synthesis. Non-sterol isoprenoids have critical biological functions in the post-translational modifications of numerous signaling molecules via prenylation, including inflammasomes. A defect in prenylation impacts protein trafficking and localization and increases proinflammatory cytokine production. Deficiency of the enzymes in the MVK pathway is known to cause systemic autoinflammatory diseases with a broad spectrum of clinical manifestations. Anticholesterol drug statins, which block the second enzyme in this pathway, HMG-CoA reductase, can lead to muscle inflammation. We report biallelic loss-of-function variants in the HMGCS1 gene, which encodes for the first enzyme in the MVK pathway, in four patients from three unrelated families who presented with recurrent fever, arthritis, abdominal pain, and progressive myositis. Three patients were homozygous for a rare variant, c.265C>T (p.Arg89Trp), predicted to be deleterious by multiple algorithms. One patient was homozygous for the novel c.572G>C (p.Arg191Pro) variant classified as VUS. The enzyme activity of both mutant HMGCS1 proteins was decreased, suggesting a deleterious effect on the protein function. Preliminary results showed that these missense variants do not affect protein expression or dimerization, which is critical for protein activity. The PBMCs from patients and CRISPR/cas9–edited HMGSC1-deficient cells showed a defect in prenylation, confirming the involvement of the MVK pathway. HMGCS1-deficient cells displayed an elevated level of IL-1β and IL-18 in response to stimulation with Pam3CSK4 and IFNγ, indicating that HMGCS1 deficiency led to inflammasome activation, which was independent of NLRP3 but was dependent on pyrin. UMAP analysis of peripheral blood single-cell RNA sequencing identified two major cell clusters: NK cells and monocytes. The most differentially upregulated pathways include oxygen/CO2 transport genes, cell death genes, and NF-κB signaling. Intracellular cytokine staining identified a significant increase of IL-1 β, IL-6, and IFNγ in all monocyte subsets of affected patients compared with unaffected relatives. RNA sequencing of frozen muscle tissues detected strong type I and II IFN signatures. Treatment with a JAK inhibitor ameliorated systemic and muscle inflammation in two patients. Further studies are in progress to understand the spectrum of immune dysregulation associated with the HMGCS1 deficiency.

OBJECTIVES:The study objective was to determine if a common single nucleotide polymorphism in the interleukin 6 (IL-6) receptor (rs2228145, p.Asp358Ala) predicted treatment response to tocilizumab in giant cell arteritis (GCA). METHODS:Genetic sequencing of the rs2228145 locus was performed in 2 independent cohorts of patients with GCA. Peripheral blood mononuclear cells (PBMCs) from patients and controls were evaluated for expression of the interleukin 6 receptor (IL-6R) and its coreceptor, gp130, using flow cytometry. The same PBMCs were stimulated with IL-6 and evaluated for downstream targets of IL-6: STAT3 phosphorylation (pSTAT3) and IL-17A expression. RESULTS:In total, 100 patients with GCA were included (derivation cohort n = 58; validation cohort n = 42). The rs2228145 variant predicted tocilizumab response in each cohort. In the derivation cohort, a gene dose-dependent response was observed with a 36% response rate in the homozygous patients and 95% response rate in patients without the variant (P = .003). In the validation cohort, tocilizumab response rates were 50% for homozygotes and 85% for patients without the variant (P = .04). pSTAT3 levels were significantly increased in response to IL-6 stimulation in a gene dose-dependent manner in CD4 T cells from patients with GCA but not controls. CD4 T cells from patients with GCA had significantly higher membrane expression of gp130 than healthy controls, and response to IL-6 correlated with gp130 expression. IL-17 producing CD4 T cells were increased in a gene dose-dependent response to IL-6 (P < .01). CONCLUSIONS:The rs2228145 variant is associated with decreased treatment response to tocilizumab and worse outcomes in GCA by enhancing CD4 T cell response to IL-6.

Cytokines function as communication tools of the immune system, serving critical functions in many biological responses and shaping the immune response. When cytokine production or their biological activity goes awry, the homeostatic balance of the immune response is altered, leading to the development of several pathologies such as autoimmune and inflammatory disorders. Cytokines bind to specific receptors on cells, triggering the activation of intracellular enzymes known as Janus kinases (JAKs). The JAK family comprises four members, JAK1, JAK2, JAK3 and tyrosine kinase 2, which are critical for intracellular cytokine signalling. Since the mid-2010s multiple JAK inhibitors have been approved for inflammatory and haematological indications. Currently, approved JAK inhibitors have demonstrated clinical efficacy; however, improved selectivity for specific JAKs is likely to enhance safety profiles, and different strategies have been used to accomplish enhanced JAK selectivity. In this update, we discuss the background of JAK inhibitors, current approved indications and adverse effects, along with new developments in this field. We address the issue of JAK selectivity and its relevance in terms of efficacy, and describe new modalities of JAK targeting, as well as new aspects of JAK inhibitor action. This Review provides an update on developments in Janus kinase inhibitors, including new disease indications and adverse effects. The authors discuss issues surrounding selectivity and efficacy, as well as new routes for administration of Janus kinase inhibitors.

OBJECTIVES:To study the molecular pathogenesis of PAPA (pyogenic arthritis, pyoderma gangrenosum and acne) syndrome, a debilitating hereditary autoinflammatory disease caused by dominant mutation in PSTPIP1.METHODS:Gene knock-out and knock-in mice were generated to develop an animal model. THP1 and retrovirally transduced U937 human myeloid leukaemia cell lines, peripheral blood mononuclear cells, small interfering RNA (siRNA) knock-down, site-directed mutagenesis, cytokine immunoassays, coimmunoprecipitation and immunoblotting were used to study inflammasome activation. Cytokine levels in the skin were evaluated by immunohistochemistry. Responsiveness to Janus kinase (JAK) inhibitors was evaluated ex vivo with peripheral blood mononuclear cells and in vivo in five treatment-refractory PAPA patients.RESULTS:The knock-in mouse model of PAPA did not recapitulate the human disease. In a human myeloid cell line model, PAPA-associated PSTPIP1 mutations activated the pyrin inflammasome, but not the NLRP3, NLRC4 or AIM2 inflammasomes. Pyrin inflammasome activation was independent of the canonical pathway of pyrin serine dephosphorylation and was blocked by the p.W232A PSTPIP1 mutation, which disrupts pyrin-PSTPIP1 interaction. IFN-γ priming of monocytes from PAPA patients led to IL-18 release in a pyrin-dependent manner. IFN-γ was abundant in the inflamed dermis of PAPA patients, but not patients with idiopathic pyoderma gangrenosum. Ex vivo JAK inhibitor treatment attenuated IFN-γ-mediated pyrin induction and IL-18 release. In 5/5 PAPA patients, the addition of JAK inhibitor therapy to IL-1 inhibition was associated with clinical improvement.CONCLUSION:PAPA-associated PSTPIP1 mutations trigger a pyrin-IL-18-IFN-γ positive feedback loop that drives PAPA disease activity and is a target for JAK inhibition.

Fundamental insight gained over the last decades led to the discovery of cytokines as pivotal drivers of inflammatory diseases such as rheumatoid arthritis, psoriasis/psoriasis arthritis, inflammatory bowel diseases, atopic dermatitis and spondylarthritis. A deeper understanding of the pro-inflammatory and anti-inflammatory effects of various cytokines has prompted new cytokine-targeting therapies, which revolutionised the treatment options in the last years for patients with inflammatory disorders. Disease-associated immune responses typically involve a complex interplay of multiple cytokines. Therefore, blockade of one single cytokine does not necessarily lead to a persistent remission in all patients with inflammatory disorders and fostered new therapeutic strategies targeting intracellular pathways shared by multiple cytokines. By inhibiting JAK-STAT signalling pathways common to families of cytokines, JAK-inhibitors (JAKinibs) have created a new paradigm for the treatment of inflammatory diseases. Multiple agents have been approved for various disorders and more are being investigated for several new indications. Second-generation selective JAKinibs have been devised with the aim to achieve an increased selectivity and a possible reduced risk of side effects. In the current review, we will summarise the current body of evidence of pan versus selective JAKinibs and the most recent insights on new side effects and indications, including COVID-19.

Natural killer (NK) cells and type 1 innate lymphoid cells (ILC1) require signal transducer and activator of transcription 4 (STAT4) to elicit rapid effector responses and protect against pathogens. By combining genetic and transcriptomic approaches, we uncovered divergent roles for STAT4 in regulating effector differentiation of these functionally related cell types. Stat4 deletion in Ncr1-expressing cells led to impaired NK cell terminal differentiation as well as to an unexpected increased generation of cytotoxic ILC1 during intestinal inflammation. Mechanistically, Stat4-deficient ILC1 exhibited upregulation of gene modules regulated by STAT5 in vivo and an aberrant effector differentiation upon in vitro stimulation with IL-2, used as a prototypical STAT5 activator. Moreover, STAT4 expression in NCR+ innate lymphocytes restrained gut inflammation in the dextran sulfate sodium-induced colitis model limiting pathogenic production of IL-13 from adaptive CD4+ T cells in the large intestine. Collectively, our data shed light on shared and distinctive mechanisms of STAT4-regulated transcriptional control in NK cells and ILC1 required for intestinal inflammatory responses.

OBJECTIVE:Systemic lupus erythematosus (SLE) increases cardiovascular disease (CVD) risk, and this is not explained by traditional risk factors. Characterization of blood immunologic signatures that associate with subclinical CVD and predict its progression has been challenging and may help identify subgroups at risk. METHODS:Patients with SLE (n = 77) and healthy controls (HCs) (n = 27) underwent assessments of arterial stiffness, vascular wall inflammation, and coronary atherosclerosis burden with cardio-ankle vascular index (CAVI); fluorodeoxyglucose-positron emission tomography/computed tomography (CT) (target-to-background ratio [TBR]); and coronary CT angiography. Whole blood bulk RNA sequencing was performed in a subset of study participants (HC n = 10, SLE n = 20). In a partially overlapping subset (HC n = 24, SLE n = 64), serum inflammatory protein biomarkers were quantified with an Olink platform. RESULTS:CAVI, TBR, and noncalcified coronary plaque burden (NCB) were increased in patients with SLE compared to HCs. When comparing patients with SLE with high CAVI scores to those with low CAVI scores or to HCs, there was a down-regulation of genes in pathways involved in the cell cycle and differentially regulated pathways related to metabolism. Distinct serum proteins associated with increased CAVI (CCL23, colony-stimulating factor 1, latency-activating peptide transforming growth factor β1, interleukin 33 [IL-33], CD8A, and IL-12B), NCB (monocyte chemotactic protein 4 and FMS-like tyrosine kinase 3 ligand [Flt3L]), and TBR (CD5, IL-1α, AXIN1, cystatin D [CST5], and tumor necrosis factor receptor superfamily 9; P < 0.05). CONCLUSION:Blood gene expression patterns and serum proteins that associate with worse vascular phenotypes suggest dysregulated immune and metabolic pathways linked to premature CVD. Cytokines and chemokines identified in associations with arterial stiffness, inflammation, and NCB in SLE may allow for characterization of new CVD biomarkers in lupus.

BACKGROUND:Cytokines are soluble factors that affect host defense and maintain immune homeostasis. Altered cytokine production leads to a dysfunctional immune responses and immune-related diseases. Cytokines bind to specific receptors and trigger various intracellular signaling cascades and targeting cytokines and/or their receptors has been effective in treating inflammatory diseases. OBJECTIVES:Type I and II cytokine receptors activate four Janus kinases (JAKs), namely JAK1, JAK2, JAK3 and TYK2 and targeting of these enzymes resulted in the development of successful drugs now referred as JAK inhibitors or JAKinibs. RESULTS:JAKinibs can be divided in three "generations." First-generation JAKinibs, molecules acting in an orthosteric manner, inhibit multiple JAKs and interfere with the biologic activity of many factors. With the idea of reducing side effects, second-generation JAKinibs, still orthosteric ATP competitors, have been developed with increased selectivity towards one or two JAKs. Third-generation JAKinibs have exploited our increased understanding of the structure and function of JAK domains and are allosteric inhibitors as they bind to specific residues in the pseudokinase domain. These third generation JAKInb indeed seems to possess a better safety profile. Notably, inhibition of cytokine activity in specific tissues could be more important than selective enzymatic blockade and for this reason, topical, inhaled, or as a non-absorbable JAKinibs are also being developed. CONCLUSIONS:While JAKinibs entered the clinical arena about ten years ago, our understanding of these drugs and their selectivity relative to their activity and safety is still incomplete. More research is therefore needed to achieve better usage of these class of drugs.

OBJECTIVES:Ageing and inflammation are associated with clonal haematopoiesis (CH), the emergence of somatic mutations in haematopoietic cells. This study details CH in patients with systemic vasculitis in association with clinical, haematological and immunological parameters. METHODS:Patients with three forms of vasculitis were screened for CH in peripheral blood by error-corrected sequencing. Relative contributions of age and vasculitis on CH prevalence were calculated using multivariable logistic regression. Clonal hierarchies were assessed by proteogenomic single-cell DNA sequencing, and functional experiments were performed in association with CH status. RESULTS:Patients with Takayasu's arteritis (TAK; n=70; mean age=33.2 years), antineutrophil cytoplasmic antibody-associated vasculitis (AAV; n=47; mean age=55.3 years) and giant cell arteritis (GCA; n=59; mean age=71.2 years) were studied. CH, most commonly in DNMT3A and TET2, was detected in 34% (60/176) of patients versus 18% (28/151) of age-matched controls (p<0.01). Prevalence of CH was independently associated with age (standardised B=0.96, p<0.01) and vasculitis (standardised B=0.46, p<0.01), occurring in 61%, 32% and 13% of patients with GCA, AAV and TAK, respectively. Both branched and linear clonal trajectories showed myeloid-lineage bias, and CH was associated with markers of cellular activation. In GCA, mutations were detected in temporal artery biopsies, and clinical relapse correlated with CH in a dose-dependent relationship with clone size. CONCLUSIONS:Age was more strongly associated with CH prevalence than inflammation in systemic vasculitis. Clonal profile was dominated by DNMT3A mutations which were associated with relapse in GCA. CH is not likely a primary causal factor in systemic vasculitis but may contribute to inflammation.

Janus kinase (JAK) inhibitors improve antitumor responses

The linear ubiquitin assembly complex (LUBAC) consists of HOIP, HOIL-1 and SHARPIN and is essential for proper immune responses. Individuals with HOIP and HOIL-1 deficiencies present with severe immunodeficiency, autoinflammation and glycogen storage disease. In mice, the loss of Sharpin leads to severe dermatitis due to excessive keratinocyte cell death. Here, we report two individuals with SHARPIN deficiency who manifest autoinflammatory symptoms but unexpectedly no dermatological problems. Fibroblasts and B cells from these individuals showed attenuated canonical NF-κB responses and a propensity for cell death mediated by TNF superfamily members. Both SHARPIN-deficient and HOIP-deficient individuals showed a substantial reduction of secondary lymphoid germinal center B cell development. Treatment of one SHARPIN-deficient individual with anti-TNF therapies led to complete clinical and transcriptomic resolution of autoinflammation. These findings underscore the critical function of the LUBAC as a gatekeeper for cell death-mediated immune dysregulation in humans.

BACKGROUND:Disabling pansclerotic morphea (DPM) is a rare systemic inflammatory disorder, characterized by poor wound healing, fibrosis, cytopenias, hypogammaglobulinemia, and squamous-cell carcinoma. The cause is unknown, and mortality is high. METHODS:We evaluated four patients from three unrelated families with an autosomal dominant pattern of inheritance of DPM. Genomic sequencing independently identified three heterozygous variants in a specific region of the gene that encodes signal transducer and activator of transcription 4 (STAT4). Primary skin fibroblast and cell-line assays were used to define the functional nature of the genetic defect. We also assayed gene expression using single-cell RNA sequencing of peripheral-blood mononuclear cells to identify inflammatory pathways that may be affected in DPM and that may respond to therapy. RESULTS:Genome sequencing revealed three novel heterozygous missense gain-of-function variants in STAT4. In vitro, primary skin fibroblasts showed enhanced interleukin-6 secretion, with impaired wound healing, contraction of the collagen matrix, and matrix secretion. Inhibition of Janus kinase (JAK)-STAT signaling with ruxolitinib led to improvement in the hyperinflammatory fibroblast phenotype in vitro and resolution of inflammatory markers and clinical symptoms in treated patients, without adverse effects. Single-cell RNA sequencing revealed expression patterns consistent with an immunodysregulatory phenotype that were appropriately modified through JAK inhibition. CONCLUSIONS:Gain-of-function variants in STAT4 caused DPM in the families that we studied. The JAK inhibitor ruxolitinib attenuated the dermatologic and inflammatory phenotype in vitro and in the affected family members. (Funded by the American Academy of Allergy, Asthma, and Immunology Foundation and others.).

Dermatomyositis (DM), antisynthetase syndrome (AS), immune-mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM) are four major types of idiopathic inflammatory myopathy (IIM). Muscle biopsies from each type of IIM have unique transcriptomic profiles. MicroRNAs (miRNAs) target messenger RNAs (mRNAs), thereby regulating their expression and modulating transcriptomic profiles. In this study, 18 DM, 12 IMNM, 6 AS, 6 IBM, and 6 histologically normal muscle biopsies underwent miRNA profiling using the NanoString nCounter system. Eleven miRNAs were exclusively differentially expressed in DM compared to controls, seven miRNAs were only differentially expressed in AS, and nine miRNAs were specifically upregulated in IBM. No differentially expressed miRNAs were identified in IMNM. We also analyzed miRNA-mRNA associations to identify putative targets of differentially expressed miRNAs. In DM and AS, these were predominantly related to inflammation and cell cycle progression. Moreover, our analysis showed an association between miR-30a-3p, miR-30e-3p, and miR-199b-5p downregulation in DM and the upregulation of target genes induced by type I interferon. In conclusion, we show that muscle biopsies from DM, AS, and IBM patients have unique miRNA signatures and that these miRNAs might play a role in regulating the expression of genes known to be involved in IIM pathogenesis.