Patients with systemic lupus erythematosus (SLE) display a complex blood transcriptome whose cellular origin is poorly resolved. Using single-cell RNA sequencing, we profiled ~276,000 peripheral ...blood mononuclear cells from 33 children with SLE with different degrees of disease activity and 11 matched controls. Increased expression of interferon-stimulated genes (ISGs) distinguished cells from children with SLE from healthy control cells. The high ISG expression signature (ISG
) derived from a small number of transcriptionally defined subpopulations within major cell types, including monocytes, CD4
and CD8
T cells, natural killer cells, conventional and plasmacytoid dendritic cells, B cells and especially plasma cells. Expansion of unique subpopulations enriched in ISGs and/or in monogenic lupus-associated genes classified patients with the highest disease activity. Profiling of ~82,000 single peripheral blood mononuclear cells from adults with SLE confirmed the expansion of similar subpopulations in patients with the highest disease activity. This study lays the groundwork for resolving the origin of the SLE transcriptional signatures and the disease heterogeneity towards precision medicine applications.
Autoantibodies against nucleic acids and excessive type I interferon (IFN) are hallmarks of human systemic lupus erythematosus (SLE). We previously reported that SLE neutrophils exposed to TLR7 ...agonist autoantibodies release interferogenic DNA, which we now demonstrate to be of mitochondrial origin. We further show that healthy human neutrophils do not complete mitophagy upon induction of mitochondrial damage. Rather, they extrude mitochondrial components, including DNA (mtDNA), devoid of oxidized (Ox) residues. When mtDNA undergoes oxidation, it is directly routed to lysosomes for degradation. This rerouting requires dissociation from the transcription factor A mitochondria (TFAM), a dual high-mobility group (HMG) protein involved in maintenance and compaction of the mitochondrial genome into nucleoids. Exposure of SLE neutrophils, or healthy IFN-primed neutrophils, to antiribonucleotide protein autoantibodies blocks TFAM phosphorylation, a necessary step for nucleoid dissociation. Consequently, Ox nucleoids accumulate within mitochondria and are eventually extruded as potent interferogenic complexes. In support of the in vivo relevance of this phenomenon, mitochondrial retention of Ox nucleoids is a feature of SLE blood neutrophils, and autoantibodies against Ox mtDNA are present in a fraction of patients. This pathway represents a novel therapeutic target in human SLE.
Adenosine deaminase 2 (ADA2) is an enzyme involved in purine metabolism and a growth factor that influences the development of endothelial cells and leukocytes. This study shows that defects in ADA2 ...cause recurrent fevers, vascular pathologic features, and mild immunodeficiency.
Patients with autoinflammatory disease sometimes present with clinical findings that encompass multiple organ systems.
1
Three unrelated children presented to the National Institutes of Health (NIH) Clinical Center with intermittent fevers, recurrent lacunar strokes, elevated levels of acute-phase reactants, livedoid rash, hepatosplenomegaly, and hypogammaglobulinemia. Collectively, these findings do not easily fit with any of the known inherited autoinflammatory diseases.
Hereditary or acquired vascular disorders can have protean manifestations yet be caused by mutations in a single gene. Diseases such as the Aicardi–Goutières syndrome,
2
,
3
polypoidal choroidal vasculopathy,
4
sickle cell anemia,
5
livedoid vasculopathy,
6
and the small-vessel vasculitides
7
,
8
are examples of systemic . . .
Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a breakdown of tolerance to nuclear antigens and the development of immune complexes. Genomic approaches have ...shown that human SLE leukocytes homogeneously express type I interferon (IFN)-induced and neutrophil-related transcripts. Increased production and/or bioavailability of IFN-α and associated alterations in dendritic cell (DC) homeostasis have been linked to lupus pathogenesis. Although neutrophils have long been shown to be associated with lupus, their potential role in disease pathogenesis remains elusive. Here, we show that mature SLE neutrophils are primed in vivo by type I IFN and die upon exposure to SLE-derived anti-ribonucleoprotein antibodies, releasing neutrophil extracellular traps (NETs). SLE NETs contain DNA as well as large amounts of LL37 and HMGB1, neutrophil proteins that facilitate the uptake and recognition of mammalian DNA by plasmacytoid DCs (pDCs). Indeed, SLE NETs activate pDCs to produce high levels of IFN-α in a DNA- and TLR9 (Toll-like receptor 9)-dependent manner. Our results reveal an unsuspected role for neutrophils in SLE pathogenesis and identify a novel link between nucleic acid-recognizing antibodies and type I IFN production in this disease.
Systemic onset juvenile idiopathic arthritis (SoJIA) encompasses approximately 10% of cases of arthritis that begin in childhood. The disease is unique in terms of clinical manifestations, severity ...of joint involvement, and lack of response to tumor necrosis factor blockade. Here, we show that serum from SoJIA patients induces the transcription of innate immunity genes, including interleukin (IL)-1 in healthy peripheral blood mononuclear cells (PBMCs). Upon activation, SoJIA PBMCs release large amounts of IL-1beta. We administered recombinant IL-1 receptor antagonist to nine SoJIA patients who were refractory to other therapies. Complete remission was obtained in seven out of nine patients and a partial response was obtained in the other two patients. We conclude that IL-1 is a major mediator of the inflammatory cascade that underlies SoJIA and that this cytokine represents a target for therapy in this disease.
Prior studies have demonstrated abnormalities in the composition of the gastrointestinal microbiota in pediatric and adult patients with spondyloarthritis (SpA). In particular, diminished fecal ...abundance of Faecalibacterium prausnitzii and abnormalities in both directions in the abundance of the Bacteroides genus have been identified.
We obtained fecal specimens from 30 children with treatment-naïve enthesitis-related arthritis (ERA) and 19 healthy controls, as well as specimens from 11 adult patients with longstanding SpA and 10 adult healthy controls. All of the samples underwent sequencing of the 16S ribosomal DNA. A subset of the pediatric fecal samples was subjected to shotgun metagenomics sequencing.
ERA patients had decreased abundance of the anti-inflammatory F. prausnitzii A2-165 strain (41 ± 28% versus 54 ± 20% of all sequences matching F. prausnitzii, p = 0.084) and an increased abundance of the control F. prausnitzii L2/6 strain (28 ± 28% versus 15 ± 15%, p = 0.038). Similar trends were observed in adults with longstanding SpA (n = 11) and controls (n = 10). In contrast, the fecal abundance of Bacteroides fragilis was increased in ERA subjects (2.0 ± 4.0% versus 0.45 ± 0.7% of all sequences, p = 0.045), yet was diminished in adult subjects (0.2 ± % versus 1.0 ± % of all sequences, p = 0.106). Shotgun metagenomics sequencing of the fecal DNA in the pediatric subjects revealed diminished coverage of the butanoate pathway (abundance normalized to controls of 1 ± 0.48 versus 0.72 ± 0.33 in ERA, p = 0.037).
The anti-inflammatory F. prausnitzii A2-165 strain appears to be depleted in both pediatric and adult SpA. In contrast, B. fragilis may be depleted in adult disease yet abundant in pediatric SpA, suggesting developmental effects on the immune system.
Glucocorticoids are widely used to treat patients with autoimmune diseases such as systemic lupus erythematosus (SLE). However, regimens used to treat many such conditions cannot maintain disease ...control in the majority of SLE patients and more aggressive approaches such as high-dose methylprednisolone pulse therapy are used to provide transient reductions in disease activity. The primary anti-inflammatory mechanism of glucocorticoids is thought to be NF- B inhibition. Recognition of self nucleic acids by toll-like receptors TLR7 and TLR9 on B cells and plasmacytoid dendritic cells (PDCs) is an important step in the pathogenesis of SLE, promoting anti-nuclear antibodies and the production of type I interferon (IFN), both correlated with the severity of disease. Following their activation by self-nucleic acid-associated immune complexes, PDCs migrate to the tissues. We demonstrate, in vitro and in vivo, that stimulation of PDCs through TLR7 and 9 can account for the reduced activity of glucocorticoids to inhibit the IFN pathway in SLE patients and in two lupus-prone mouse strains. The triggering of PDCs through TLR7 and 9 by nucleic acid-containing immune complexes or by synthetic ligands activates the NF- B pathway essential for PDC survival. Glucocorticoids do not affect NF- B activation in PDCs, preventing glucocorticoid induction of PDC death and the consequent reduction of systemic IFN- levels. These findings unveil a new role for self nucleic acid recognition by TLRs and indicate that inhibitors of TLR7 and 9 signalling could prove to be effective corticosteroid-sparing drugs.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Childhood-onset systemic lupus erythematosus (cSLE) is an autoimmune disease that results in significant damage and often needs more aggressive treatment. Compared to adult-onset SLE, cSLE has a ...stronger genetic background and more prevalent elevated type I Interferon expression. The management of cSLE is more challenging because the disease itself and treatment can affect physical, psychological and emotional growth and development. High dose oral glucocorticoid (GC) has become the rule for treating moderate to severe cSLE activity. However, GC-related side effects and potential toxicities are problems that cannot be ignored. Recent studies have suggested that GC pulse therapy can achieve disease remission rapidly and reduce GC-related side effects with a reduction in oral prednisone doses. This article reviews characteristics, including pathogenesis and manifestations of cSLE, and summarized the existing evidence on GC therapy, especially on GC pulse therapy in cSLE, followed by our proposal for GC therapy according to the clinical effects and pathogenesis.
Juvenile idiopathic arthritis, formerly known as juvenile rheumatoid arthritis, is a heterogeneous group of diseases characterized by onset of chronic arthritis in childhood. Diagnosis requires onset ...of disease by age 16 years, persistent arthritis in any joint for ≥ 6 weeks, and exclusion of other conditions that cause arthritis (eg, infection, malignancy, acute rheumatic fever, inflammatory bowel disease). Most patients with juvenile idiopathic arthritis present with subacute arthritis with minimal pain and few constitutional symptoms. Laboratory evaluation and imaging are useful to exclude other diagnoses and establish the presence of systemic inflammation. However, these modalities are of limited value in screening for rheumatic diseases, and they may be misleading because of the high rate of false-positive results. Most rheumatologic conditions are diagnosed based on pattern recognition, which is established with a thorough history and physical examination.
Lupus nephritis is one of the most common and serious complications of systemic lupus erythematosus (SLE) in childhood affecting more than 80 % of patients. Treatment of this complication has ...undergone significant evolution in recent years. A series of randomized controlled trials has clarified the role of a variety of immunomodulating regimens including some novel biologic medications. This review touches on the major trials that have influenced practice and shaped current thinking about the treatment of proliferative lupus glomerulonephritis.
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