Monogenic autoinflammatory syndromes present with excessive systemic inflammation including fever, rashes, arthritis, and organ-specific inflammation and are caused by defects in single genes ...encoding proteins that regulate innate inflammatory pathways. Pathogenic variants in two interleukin-1 (IL-1)-regulating genes, NLRP3 and IL1RN, cause two severe and early-onset autoinflammatory syndromes, CAPS (cryopyrin associated periodic syndromes) and DIRA (deficiency of IL-1 receptor antagonist). The discovery of the mutations that cause CAPS and DIRA led to clinical and basic research that uncovered the key role of IL-1 in an extended spectrum of immune dysregulatory conditions. NLRP3 encodes cryopyrin, an intracellular "molecular sensor" that forms a multimolecular platform, the NLRP3 inflammasome, which links "danger recognition" to the activation of the proinflammatory cytokine IL-1β. The success and safety profile of drugs targeting IL -1 in the treatment of CAPS and DIRA have encouraged their wider use in other autoinflammatory syndromes including the classic hereditary periodic fever syndromes (familial Mediterranean fever, TNF receptor-associated periodic syndrome, and hyperimmunoglobulinemia D with periodic fever syndrome) and additional immune dysregulatory conditions that are not genetically well defined, including Still's, Behcet's, and Schnitzler diseases. The fact that the accumulation of metabolic substrates such as monosodium urate, ceramide, cholesterol, and glucose can trigger the NLRP3 inflammasome connects metabolic stress to IL-1β-mediated inflammation and provides a rationale for therapeutically targeting IL-1 in prevalent diseases such as gout, diabetes mellitus, and coronary artery disease.
Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening hyperferritinemic systemic inflammatory disorders. Although profound cytotoxic impairment causes ...familial HLH (fHLH), the mechanisms driving non-fHLH and MAS are largely unknown. MAS occurs in patients with suspected rheumatic disease, but the mechanistic basis for its distinction is unclear. Recently, a syndrome of recurrent MAS with infantile enterocolitis caused by NLRC4 inflammasome hyperactivity highlighted the potential importance of interleukin-18 (IL-18). We tested this association in hyperferritinemic and autoinflammatory patients and found a dramatic correlation of MAS risk with chronic (sometimes lifelong) elevation of mature IL-18, particularly with IL-18 unbound by IL-18 binding protein, or free IL-18. In a mouse engineered to carry a disease-causing germ line NLRC4T337S mutation, we observed inflammasome-dependent, chronic IL-18 elevation. Surprisingly, this NLRC4T337S-induced systemic IL-18 elevation derived entirely from intestinal epithelia. NLRC4T337S intestines were histologically normal but showed increased epithelial turnover and upregulation of interferon-γ–induced genes. Assessing cellular and tissue expression, classical inflammasome components such as Il1b, Nlrp3, and Mefv predominated in neutrophils, whereas Nlrc4 and Il18 were distinctly epithelial. Demonstrating the importance of free IL-18, Il18 transgenic mice exhibited free IL-18 elevation and more severe experimental MAS. NLRC4T337S mice, whose free IL-18 levels were normal, did not. Thus, we describe a unique connection between MAS risk and chronic IL-18, identify epithelial inflammasome hyperactivity as a potential source, and demonstrate the pathogenicity of free IL-18. These data suggest an IL-18–driven pathway, complementary to the cytotoxic impairment of fHLH, with potential as a distinguishing biomarker and therapeutic target in MAS.
•IL-18 distinguishes susceptibility to MAS amongst hyperferritinemic and autoinflammatory diseases.•Excess IL-18 in NLRC4 gain-of-function mice derives from intestinal epithelia, and free IL-18 promotes experimental MAS.
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Population pharmacokinetic (popPK) modeling was used to characterize the PK profile of the oral Janus kinase (JAK)1/JAK2 inhibitor, baricitinib, in 18 patients with Mendelian interferonopathies who ...are enrolled in a compassionate use program. Patients received doses between 0.1 to 17 mg per day. Covariates of weight and renal function significantly influenced volume‐of‐distribution and clearance, respectively. The half‐life of baricitinib in patients less than 40 kg was substantially shorter than in adult populations, requiring the need for dosing up to 4 times daily. On therapeutic doses, the mean area‐under‐the‐concentration‐vs.‐time curve was 2,388 nM*hr, which is 1.83‐fold higher than mean baricitinib exposures in adult patients with rheumatoid arthritis receiving doses of 4 mg once‐daily. Dose‐dependent decreases in interferon (IFN) biomarkers confirmed an in vivo effect of baricitinib on type‐1 IFN signaling. PopPK and pharmacodynamic data support a proposal for a weight‐ and estimated glomerular filtration rate‐based dosing regimen in guiding baricitinib dosing in patients with rare interferonopathies.
Inflammasomes are innate immune sensors that respond to pathogen- and damage-associated signals with caspase-1 activation, interleukin (IL)-1β and IL-18 secretion, and macrophage pyroptosis. The ...discovery that dominant gain-of-function mutations in NLRP3 cause the cryopyrin-associated periodic syndromes (CAPS) and trigger spontaneous inflammasome activation and IL-1β oversecretion led to successful treatment with IL-1-blocking agents. Herein we report a de novo missense mutation (c.1009A > T, encoding p.Thr337Ser) affecting the nucleotide-binding domain of the inflammasome component NLRC4 that causes early-onset recurrent fever flares and macrophage activation syndrome (MAS). Functional analyses demonstrated spontaneous inflammasome formation and production of the inflammasome-dependent cytokines IL-1β and IL-18, with the latter exceeding the levels seen in CAPS. The NLRC4 mutation caused constitutive caspase-1 cleavage in cells transduced with mutant NLRC4 and increased production of IL-18 in both patient-derived and mutant NLRC4-transduced macrophages. Thus, we describe a new monoallelic inflammasome defect that expands the monogenic autoinflammatory disease spectrum to include MAS and suggests new targets for therapy.
Objective
To identify novel heterozygous LPIN2 mutations in a patient with Majeed syndrome and characterize the pathomechanisms that lead to the development of sterile osteomyelitis.
Methods
Targeted ...genetic analysis and functional studies assessing monocyte responses, macrophage differentiation, and osteoclastogenesis were conducted to compare the pathogenesis of Majeed syndrome to interleukin‐1 (IL‐1)–mediated diseases including neonatal‐onset multisystem inflammatory disease (NOMID) and deficiency of the IL‐1 receptor antagonist (DIRA).
Results
A 4‐year‐old girl of mixed ethnic background presented with sterile osteomyelitis and elevated acute‐phase reactants. She had a 17.8‐kb deletion on the maternal LPIN2 allele and a splice site mutation, p.R517H, that variably spliced out exons 10 and 11 on the paternal LPIN2 allele. The patient achieved long‐lasting remission receiving IL‐1 blockade with canakinumab. Compared to controls, monocytes and monocyte‐derived M1‐like macrophages from the patient with Majeed syndrome and those with NOMID or DIRA had elevated caspase 1 activity and IL‐1β secretion. In contrast, lipopolysaccharide‐stimulated, monocyte‐derived, M2‐like macrophages from the patient with Majeed syndrome released higher levels of osteoclastogenic mediators (IL‐8, IL‐6, tumor necrosis factor, CCL2, macrophage inflammatory protein 1α/β, CXCL8, and CXCL1) compared to NOMID patients and healthy controls. Accelerated osteoclastogenesis in the patient with Majeed syndrome was associated with higher NFATc1 levels, enhanced JNK/MAPK, and reduced Src kinase activation, and partially responded to JNK inhibition and IL‐1 (but not IL‐6) blockade.
Conclusion
We report 2 novel compound heterozygous disease‐causing mutations in LPIN2 in an American patient with Majeed syndrome. LPIN2 deficiency drives differentiation of proinflammatory M2‐like macrophages and enhances intrinsic osteoclastogenesis. This provides a model for the pathogenesis of sterile osteomyelitis which differentiates Majeed syndrome from other IL‐1–mediated autoinflammatory diseases.
Monogenic IFN-mediated autoinflammatory diseases present in infancy with systemic inflammation, an IFN response gene signature, inflammatory organ damage, and high mortality. We used the JAK ...inhibitor baricitinib, with IFN-blocking activity in vitro, to ameliorate disease.
Between October 2011 and February 2017, 10 patients with CANDLE (chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperatures), 4 patients with SAVI (stimulator of IFN genes-associated STING-associated vasculopathy with onset in infancy), and 4 patients with other interferonopathies were enrolled in an expanded access program. The patients underwent dose escalation, and the benefit was assessed by reductions in daily disease symptoms and corticosteroid requirement. Quality of life, organ inflammation, changes in IFN-induced biomarkers, and safety were longitudinally assessed.
Eighteen patients were treated for a mean duration of 3.0 years (1.5-4.9 years). The median daily symptom score decreased from 1.3 (interquartile range IQR, 0.93-1.78) to 0.25 (IQR, 0.1-0.63) (P < 0.0001). In 14 patients receiving corticosteroids at baseline, daily prednisone doses decreased from 0.44 mg/kg/day (IQR, 0.31-1.09) to 0.11 mg/kg/day (IQR, 0.02-0.24) (P < 0.01), and 5 of 10 patients with CANDLE achieved lasting clinical remission. The patients' quality of life and height and bone mineral density Z-scores significantly improved, and their IFN biomarkers decreased. Three patients, two of whom had genetically undefined conditions, discontinued treatment because of lack of efficacy, and one CANDLE patient discontinued treatment because of BK viremia and azotemia. The most common adverse events were upper respiratory infections, gastroenteritis, and BK viruria and viremia.
Upon baricitinib treatment, clinical manifestations and inflammatory and IFN biomarkers improved in patients with the monogenic interferonopathies CANDLE, SAVI, and other interferonopathies. Monitoring safety and efficacy is important in benefit-risk assessment.
ClinicalTrials.gov NCT01724580 and NCT02974595.
This research was supported by the Intramural Research Program of the NIH, NIAID, and NIAMS. Baricitinib was provided by Eli Lilly and Company, which is the sponsor of the expanded access program for this drug.
Pediatric Coronavirus Disease 2019 (pCOVID-19) is rarely severe; however, a minority of children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might develop multisystem ...inflammatory syndrome in children (MIS-C), with substantial morbidity. In this longitudinal multi-institutional study, we applied multi-omics (analysis of soluble biomarkers, proteomics, single-cell gene expression and immune repertoire analysis) to profile children with COVID-19 (n = 110) and MIS-C (n = 76), along with pediatric healthy controls (pHCs; n = 76). pCOVID-19 was characterized by robust type I interferon (IFN) responses, whereas prominent type II IFN-dependent and NF-κB-dependent signatures, matrisome activation and increased levels of circulating spike protein were detected in MIS-C, with no correlation with SARS-CoV-2 PCR status around the time of admission. Transient expansion of TRBV11-2 T cell clonotypes in MIS-C was associated with signatures of inflammation and T cell activation. The association of MIS-C with the combination of HLA A*02, B*35 and C*04 alleles suggests genetic susceptibility. MIS-C B cells showed higher mutation load than pCOVID-19 and pHC. These results identify distinct immunopathological signatures in pCOVID-19 and MIS-C that might help better define the pathophysiology of these disorders and guide therapy.
None of the patients had a family history of consanguinity. Because of the complex nature of their disease, whole-exome sequencing (WES) was performed in all patients and identified 3 distinct ...monoallelic, heterozygous, possibly pathogenic de novo variants in CDC42. Immunophenotypic changes in monocytes and natural killer cells (Fig 1, A and B) were also noted. Because of the complex nature of the disease, WES was performed and identified a heterozygous and possibly pathogenic de novo variant in CDC42 c.563G>A (p.C188Y; Fig 1). At 8 months, he was found to have retinal detachment, phthisis of his right eye and papilledema of the left eye, both of which were presumed to be secondary to his inflammatory disease and increased intracranial pressure. Because of the patient's phenotypic similarities to patients with NOMID, he was started on prednisone and anakinra at age 8 months, with resolution of systemic inflammation and cytopenias. Patient 1 Patient 2 Patient 3 Patient 4 CDC42 variant c.563G>A (p.C188Y) c.563G>A (p.C188Y) c.556C>T (p.R186C) c.576A>C (stop lost p.*192C*24) Dose of anakinra (d) Before anakinra 1 mg/kg 2.5 mg/kg Before anakinra 6 mg/kg 5 mg/kg Before anakinra 3 mg/kg 8.5 mg/kg Canakinumab, 8 mg/kg/mo Before anakinra 3 mg/kg 4.5 mg/kg Clinical presentation Facial dysmorphism Mild frontal bossing, mild hypertelorism, depressed nasal bridge Frontal bossing, macrocephaly, thin sparse hair, depressed nasal bridge None Mild frontal bossing Weight (percentile) <3rd <3rd 5th <3rd <3rd 5th 3rd 3rd 3rd 5th <3rd <3rd 10th Appetite Poor Improved Normal Poor Improved Improved Poor Improved Improved Normal Poor Decreased Normal Spleen size∗ (cm patient age; SM or normal, UL for age) 11.4 (12 mo; SM, UL 8.0) 8 (15 mo; normal, UL 8.0) 8 (18 mo; normal, UL 8.0) 11.2 (neonatal; SM, UL 6.0) NA 10.1 (12 mo; SM, UL 8.0) 9.2 (neonatal; SM, UL 6.0) 9.9 (5 mo; SM, UL 6.5) 10.8 (16 mo; SM, UL 8.0) 11.9 (6 y; SM, UL 10.0) Hepatomegaly and SM 6.7 (15 mo old; normal, UL 8.0) NA Painful rash Daily None None Bimonthly Monthly None Daily Resolved Resolved Resolved Daily Recurrent None Ibuprofen intake Daily None None None None None None None None None None None None Severe infections None None None None None None None Lymphadenitis Lymphadenitis Lymphadenitis, streptococcal sepsis None Yes† Lymphadenitis Yes‡ Biological parameters Platelet (103/μL) 72 155 141 182 267 276 13 22 148 202 54 381 307 Hemoglobin (g/dL) Transfusion-dependent anemia (Hb, <7 g/dL) 13.8 13.3 Transfusion-dependent anemia (Hb, <7 g/dL) 11.2 11.7 8.1 7.9 10.1 12.3 7.4 13.3 13.5 RBC transfusion Monthly None None Q2-3 mo None None Weekly or biweekly Sporadic Rare Rare Multiple None None Platelet transfusion None None None None None None Multiple Sporadic Rare Rare Multiple None None LDH (ng/mL) 540 NA 547 584 269 271 817 998 1,115 1,633 NA 284 353 ESR (mm/h) >130 16 32 51 22 40 62 65 39 22 140 26 21 CRP (mg/L) 55 2 4 56 3.4 8.8 14.2 3.6 5.6 0.2 Increased 28.8 1.54 Ferritin (ng/mL <400) 2,364 801 680 614 316 126 5,191 3,682 1,329 557 NA 172 51 IL-6 (pg/mL <5) 18 NA <5 NA NA NA NA NA 15.9 11.0 NA NA NA IL-18§ (pg/mL 100-500) 35,616 27,803 22,690 36,479‖ NA 83,268 NA NA 28,407 26,402 NA 19,025 21,535 IL-18BP§ (pg/mL 1,000-6,000) 14,418 8,557 6,264 NA NA 14,653 NA NA 11,803 NA NA 23,986 9,626 CXCL9§ (pg/mL 500-3,500) 8,457 2,978 4,975 NA NA 2,064 NA NA 3,942 NA NA 11,473 4,278 Table I Clinical phenotype and biological parameters of the reported patients before and after therapy with IL-1 inhibitors TKS C-terminal∗ mutations in CDC42 Group 1 Group 2 Group 3 Clinical presentation Failure to thrive, postnatal weight (weight <2 SD) 3/5 2/4 3/4 4/4 Intellectual disability 5/5 4/4 2/6 1/4 Facial dysmorphism, including frontal bossing and large forehead 2/5 2/4 1/6 3/4 Cardiac abnormality 3/5 2/4 2/5 0/4 Rash 0/5 0/4 0/5 4/4 Recurrent severe infections 4/5 3/4 1/6 3/4 (2/3 were receiving immunosuppression) Biological parameters Thrombocytopenia 4/4 1/3 0/5 4/4 Anemia NA NA NA 4/4 Systemic inflammatory syndrome: increased CRP level, ESR, and ferritin level NA NA NA 4/4 Table E1 Comparison of the clinical phenotypes and biological parameters of patients with TKS and of our cohort of 4 patients with a de novo heterozygous C-terminal mutation in CDC42 Patient 1 CDC42 c.563G>A p.C188Y De novo Possibly pathogenic: 0.337∗ Patient 2 CDC42 LYST LPIN2 MEFV c.563G>A c.1686G>C c.446C>T c.442G>C p.C188Y p.Q562H p.P149L p.E148Q De novo Possibly pathogenic: 0.337∗ Possibly pathogenic: 0.035 Possibly pathogenic: 0.049 Likely benign: 0.024 Patient 3 CDC42 LYST UNC13D c.556C>T c.4545G>C c.2764G>A p.R186C p.E1515D p.A922T De novo Heterozygous from father Heterozygous from mother Possibly pathogenic: 0.053∗ Likely benign: 0.003 Possibly pathogenic: 0.047 Patient 4 CDC42 WAS c.576A>C (stop lost) c.706G>A p.*192C*24 p.A236T De novo X-linked from mother Possibly pathogenic: 0.053∗ Possibly pathogenic: 0.964 Table E2 WES analysis of all 4 reported patients No.
Juvenile dermatomyositis (JDM) is a systemic autoimmune disease with a prominent interferon (IFN) signature, but the pathogenesis of JDM and the etiology of its IFN signature remain unknown. The ...Mendelian autoinflammatory interferonopathies, Chronic Atypical Neutrophilic Dermatosis with Lipodystrophy and Elevated temperature (CANDLE) and STING-Associated Vasculopathy with onset in Infancy (SAVI), are caused by genetic mutations and have extremely elevated IFN signatures thought to drive pathology. The phenotypic overlap of some clinical features of CANDLE and SAVI with JDM led to the comparison of a standardized interferon-regulated gene score (IRG-S) in JDM and myositis-specific autoantibody (MSA) JDM subgroups, with CANDLE and SAVI.
A peripheral 28-component IRG-S assessed by NanoString™ in 57 JDM patients subtyped by MSA was compared with IRG-S in healthy controls (HC) and CANDLE/SAVI patients. Principal component analysis (PCA) was performed, and individual genes were evaluated for their contribution to the score. IRG-S were correlated with disease assessments and patient characteristics.
IRG-S in JDM patients were significantly higher than in HC but lower than in CANDLE or SAVI. JDM IRG-S overlapped more with SAVI than CANDLE by PCA. Among MSA groups, anti-MDA5 autoantibody-positive patients' IRG-S overlapped most with SAVI. The IFI27 proportion was significantly higher in SAVI and CANDLE than JDM, but IFIT1 contributed more to IRG-S in JDM. Overall, the contribution of individual interferon-regulated genes (IRG) in JDM was more similar to SAVI. IRG-S correlated moderately with JDM disease activity measures (r
= 0.33-0.47) and more strongly with skin activity (r
= 0.58-0.79) in anti-TIF1 autoantibody-positive patients. Weakness and joint disease activity (multinomial OR 0.91 and 3.3) were the best predictors of high IRG-S.
Our findings demonstrate peripheral IRG expression in JDM overlaps with monogenic interferonopathies, particularly SAVI, and correlates with disease activity. Anti-MDA5 autoantibody-positive JDM IRG-S were notably more similar to SAVI. This may reflect both a shared IFN signature, which is driven by IFN-β and STING pathways in SAVI, as well as the shared phenotype of vasculopathy in SAVI and JDM, particularly in anti-MDA5 autoantibody-positive JDM, and indicate potential therapeutic targets for JDM.
We have successfully created induced pluripotent stem cells (iPSC) from patients carrying a heterozygous mutation in the gene encoding STING. The gain-of-function mutation leads to constitutive ...activation of STING which leads to the development of the disease STING-associated vasculopathy with onset in infancy (SAVI). The iPSC lines derived from the SAVI patitents are shown to be morphologically and phenotypically normal and have the potential to self renew and differentiate into the three germ layers. These iPSC provide a powerful tools to investigate the role of STING in the regulation of immune responses and vascular renegeration.
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