[show abstract][hide abstract] ABSTRACT: Background We observed a syndrome of intermittent fevers, early-onset lacunar strokes and other neurovascular manifestations, livedoid rash, hepatosplenomegaly, and systemic vasculopathy in three unrelated patients. We suspected a genetic cause because the disorder presented in early childhood. Methods We performed whole-exome sequencing in the initial three patients and their unaffected parents and candidate-gene sequencing in three patients with a similar phenotype, as well as two young siblings with polyarteritis nodosa and one patient with small-vessel vasculitis. Enzyme assays, immunoblotting, immunohistochemical testing, flow cytometry, and cytokine profiling were performed on samples from the patients. To study protein function, we used morpholino-mediated knockdowns in zebrafish and short hairpin RNA knockdowns in U937 cells cultured with human dermal endothelial cells. Results All nine patients carried recessively inherited mutations in CECR1 (cat eye syndrome chromosome region, candidate 1), encoding adenosine deaminase 2 (ADA2), that were predicted to be deleterious; these mutations were rare or absent in healthy controls. Six patients were compound heterozygous for eight CECR1 mutations, whereas the three patients with polyarteritis nodosa or small-vessel vasculitis were homozygous for the p.Gly47Arg mutation. Patients had a marked reduction in the levels of ADA2 and ADA2-specific enzyme activity in the blood. Skin, liver, and brain biopsies revealed vasculopathic changes characterized by compromised endothelial integrity, endothelial cellular activation, and inflammation. Knockdown of a zebrafish ADA2 homologue caused intracranial hemorrhages and neutropenia - phenotypes that were prevented by coinjection with nonmutated (but not with mutated) human CECR1. Monocytes from patients induced damage in cocultured endothelial-cell layers. Conclusions Loss-of-function mutations in CECR1 were associated with a spectrum of vascular and inflammatory phenotypes, ranging from early-onset recurrent stroke to systemic vasculopathy or vasculitis. (Funded by the National Institutes of Health Intramural Research Programs and others.).
New England Journal of Medicine 02/2014; · 51.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Genome-wide association studies (GWAS) are a powerful means of identifying genes with disease-associated common variants, but they are not well-suited to detecting genes with disease-associated rare and low-frequency variants. In the current study of Behçet disease (BD), nonsynonymous variants (NSVs) identified by deep exonic resequencing of 10 genes found by GWAS (IL10, IL23R, CCR1, STAT4, KLRK1, KLRC1, KLRC2, KLRC3, KLRC4, and ERAP1) and 11 genes selected for their role in innate immunity (IL1B, IL1R1, IL1RN, NLRP3, MEFV, TNFRSF1A, PSTPIP1, CASP1, PYCARD, NOD2, and TLR4) were evaluated for BD association. A differential distribution of the rare and low-frequency NSVs of a gene in 2,461 BD cases compared with 2,458 controls indicated their collective association with disease. By stringent criteria requiring at least a single burden test with study-wide significance and a corroborating test with at least nominal significance, rare and low-frequency NSVs in one GWAS-identified gene, IL23R (P = 6.9 × 10(-5)), and one gene involved in innate immunity, TLR4 (P = 8.0 × 10(-4)), were associated with BD. In addition, damaging or rare damaging NOD2 variants were nominally significant across all three burden tests applied (P = 0.0063-0.045). Furthermore, carriage of the familial Mediterranean fever gene (MEFV) mutation Met694Val, which is known to cause recessively inherited familial Mediterranean fever, conferred BD risk in the Turkish population (OR, 2.65; P = 1.8 × 10(-12)). The disease-associated NSVs in MEFV and TLR4 implicate innate immune and bacterial sensing mechanisms in BD pathogenesis.
Proceedings of the National Academy of Sciences 04/2013; · 9.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: Individuals with Behçet's disease suffer from episodic inflammation often affecting the orogenital mucosa, skin and eyes. To discover new susceptibility loci for Behçet's disease, we performed a genome-wide association study (GWAS) of 779,465 SNPs with imputed genotypes in 1,209 Turkish individuals with Behçet's disease and 1,278 controls. We identified new associations at CCR1, STAT4 and KLRC4. Additionally, two SNPs in ERAP1, encoding ERAP1 p.Asp575Asn and p.Arg725Gln alterations, recessively conferred disease risk. These findings were replicated in 1,468 independent Turkish and/or 1,352 Japanese samples (combined meta-analysis P < 2 × 10(-9)). We also found evidence for interaction between HLA-B*51 and ERAP1 (P = 9 × 10(-4)). The CCR1 and STAT4 variants were associated with gene expression differences. Three risk loci shared with ankylosing spondylitis and psoriasis (the MHC class I region, ERAP1 and IL23R and the MHC class I-ERAP1 interaction), as well as two loci shared with inflammatory bowel disease (IL23R and IL10) implicate shared pathogenic pathways in the spondyloarthritides and Behçet's disease.
[show abstract][hide abstract] ABSTRACT: Cytopenias are key prognostic indicators of life-threatening infection, contributing to immunosuppression and mortality. Here we define a role for Caspase-1-dependent death, known as pyroptosis, in infection-induced cytopenias by studying inflammasome activation in hematopoietic progenitor cells. The NLRP1a inflammasome is expressed in hematopoietic progenitor cells and its activation triggers their pyroptotic death. Active NLRP1a induced a lethal systemic inflammatory disease that was driven by Caspase-1 and IL-1β but was independent of apoptosis-associated speck-like protein containing a CARD (ASC) and ameliorated by IL-18. Surprisingly, in the absence of IL-1β-driven inflammation, active NLRP1a triggered pyroptosis of hematopoietic progenitor cells resulting in leukopenia at steady state. During periods of hematopoietic stress induced by chemotherapy or lymphocytic choriomeningitis virus (LCMV) infection, active NLRP1a caused prolonged cytopenia, bone marrow hypoplasia, and immunosuppression. Conversely, NLRP1-deficient mice showed enhanced recovery from chemotherapy and LCMV infection, demonstrating that NLRP1 acts as a cellular sentinel to alert Caspase-1 to hematopoietic and infectious stress.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: To analyse gene expression patterns and to define a specific gene expression signature in patients with the severe end of the spectrum of cryopyrin-associated periodic syndromes (CAPS). The molecular consequences of interleukin 1 inhibition were examined by comparing gene expression patterns in 16 CAPS patients before and after treatment with anakinra. METHODS: We collected peripheral blood mononuclear cells from 22 CAPS patients with active disease and from 14 healthy children. Transcripts that passed stringent filtering criteria (p values ≤ false discovery rate 1%) were considered as differentially expressed genes (DEG). A set of DEG was validated by quantitative reverse transcription PCR and functional studies with primary cells from CAPS patients and healthy controls. We used 17 CAPS and 66 non-CAPS patient samples to create a set of gene expression models that differentiates CAPS patients from controls and from patients with other autoinflammatory conditions. RESULTS: Many DEG include transcripts related to the regulation of innate and adaptive immune responses, oxidative stress, cell death, cell adhesion and motility. A set of gene expression-based models comprising the CAPS-specific gene expression signature correctly classified all 17 samples from an independent dataset. This classifier also correctly identified 15 of 16 post-anakinra CAPS samples despite the fact that these CAPS patients were in clinical remission. CONCLUSIONS: We identified a gene expression signature that clearly distinguished CAPS patients from controls. A number of DEG were in common with other systemic inflammatory diseases such as systemic onset juvenile idiopathic arthritis. The CAPS-specific gene expression classifiers also suggest incomplete suppression of inflammation at low doses of anakinra.
Annals of the rheumatic diseases 12/2012; · 8.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: Mutations in the gene encoding NLRP3 cause a spectrum of autoinflammatory diseases known as cryopyrin-associated periodic syndromes (CAPS). NLRP3 is a key component of one of several distinct cytoplasmic multiprotein complexes (inflammasomes) that mediate the maturation of the proinflammatory cytokine interleukin-1β (IL-1β) by activating caspase-1. Although several models for inflammasome activation, such as K(+) efflux, generation of reactive oxygen species and lysosomal destabilization, have been proposed, the precise molecular mechanism of NLRP3 inflammasome activation, as well as the mechanism by which CAPS-associated mutations activate NLRP3, remain to be elucidated. Here we show that the murine calcium-sensing receptor (CASR) activates the NLRP3 inflammasome, mediated by increased intracellular Ca(2+) and decreased cellular cyclic AMP (cAMP). Ca(2+) or other CASR agonists activate the NLRP3 inflammasome in the absence of exogenous ATP, whereas knockdown of CASR reduces inflammasome activation in response to known NLRP3 activators. CASR activates the NLRP3 inflammasome through phospholipase C, which catalyses inositol-1,4,5-trisphosphate production and thereby induces release of Ca(2+) from endoplasmic reticulum stores. The increased cytoplasmic Ca(2+) promotes the assembly of inflammasome components, and intracellular Ca(2+) is required for spontaneous inflammasome activity in cells from patients with CAPS. CASR stimulation also results in reduced intracellular cAMP, which independently activates the NLRP3 inflammasome. cAMP binds to NLRP3 directly to inhibit inflammasome assembly, and downregulation of cAMP relieves this inhibition. The binding affinity of cAMP for CAPS-associated mutant NLRP3 is substantially lower than for wild-type NLRP3, and the uncontrolled mature IL-1β production from CAPS patients' peripheral blood mononuclear cells is attenuated by increasing cAMP. Taken together, these findings indicate that Ca(2+) and cAMP are two key molecular regulators of the NLRP3 inflammasome that have critical roles in the molecular pathogenesis of CAPS.
[show abstract][hide abstract] ABSTRACT: Chinese translation
Currently, there is no proven alternative therapy for patients with familial Mediterranean fever (FMF) that is resistant to or intolerant of colchicine. Interleukin-1 is a key proinflammatory cytokine in FMF.
To assess the efficacy and safety of rilonacept, an interleukin-1 decoy receptor, in treating patients with colchicine-resistant or -intolerant FMF.
Randomized, double-blind, single-participant alternating treatment study. (ClinicalTrials.gov number: NCT00582907).
6 U.S. sites.
Patients with FMF aged 4 years or older with 1 or more attacks per month.
One of 4 treatment sequences that each included two 3-month courses of rilonacept, 2.2 mg/kg (maximum, 160 mg) by weekly subcutaneous injection, and two 3-month courses of placebo.
Differences in the frequency of FMF attacks and adverse events between rilonacept and placebo.
8 males and 6 females with a mean age of 24.4 years (SD, 11.8) were randomly assigned. Among 12 participants who completed 2 or more treatment courses, the rilonacept-placebo attack risk ratio was 0.59 (SD, 0.12) (equal-tail 95% credible interval, 0.39 to 0.85). The median number of attacks per month was 0.77 (0.18 and 1.20 attacks in the first and third quartiles, respectively) with rilonacept versus 2.00 (0.90 and 2.40, respectively) with placebo (median difference, -1.74 [95% CI, -3.4 to -0.1]; P = 0.027). There were more treatment courses of rilonacept without attacks (29% vs. 0%; P = 0.004) and with a decrease in attacks of greater than 50% compared with the baseline rate during screening (75% vs. 35%; P = 0.006) than with placebo. However, the duration of attacks did not differ between placebo and rilonacept (median difference, 1.2 days [-0.5 and 2.4 days in the first and third quartiles, respectively]; P = 0.32). Injection site reactions were more frequent with rilonacept (median difference, 0 events per patient treatment month [medians of -4 and 0 in the first and third quartiles, respectively]; P = 0.047), but no differences were seen in other adverse events.
Small sample size, heterogeneity of FMF mutations, age, and participant indication (colchicine resistance or intolerance) were study limitations.
Rilonacept reduces the frequency of FMF attacks and seems to be a treatment option for patients with colchicine-resistant or -intolerant FMF.
U.S. Food and Drug Administration, Office of Orphan Products Development.
Annals of internal medicine 10/2012; 157(8):533-41. · 13.98 Impact Factor
[show abstract][hide abstract] ABSTRACT: Whole-exome sequencing was performed in a family affected by dominantly inherited inflammatory disease characterized by recurrent blistering skin lesions, bronchiolitis, arthralgia, ocular inflammation, enterocolitis, absence of autoantibodies, and mild immunodefi-ciency. Exome data from three samples, including the affected father and daughter and unaffected mother, were filtered for the exclusion of reported variants, along with benign variants, as determined by PolyPhen-2. A total of eight transcripts were identified as possible candidate genes. We confirmed a variant, c.2120C>A (p.Ser707Tyr), within PLCG2 as the only de novo variant that was present in two affected family members and not present in four unaffected members. PLCG2 encodes phospholipase Cg2 (PLCg2), an enzyme with a critical regulatory role in various immune and inflammatory pathways. The p.Ser707Tyr substitution is located in an autoinhi-bitory SH2 domain that is crucial for PLCg2 activation. Overexpression of the altered p.Ser707Tyr protein and ex vivo experiments using affected individuals' leukocytes showed clearly enhanced PLCg2 activity, suggesting increased intracellular signaling in the PLCg2-medi-ated pathway. Recently, our laboratory identified in individuals with cold-induced urticaria and immune dysregulation PLCG2 exon-skipping mutations resulting in protein products with constitutive phospholipase activity but with reduced intracellular signaling at physiological temperatures. In contrast, the p.Ser707Tyr substitution in PLCg2 causes a distinct inflammatory phenotype that is not provoked by cold temperatures and that has different end-organ involvement and increased intracellular signaling at physiological temperatures. Our results highlight the utility of exome-sequencing technology in finding causal mutations in nuclear families with dominantly inherited traits otherwise intractable by linkage analysis. Autoinflammatory diseases are inherited immunologic disorders caused by aberrant activation of innate immune cells, primarily neutrophils and macrophages. In a broad sense, autoinflammatory diseases could be defined as pri-mary immunodeficiencies because they result from defects in components of the innate immune response. The term autoinflammation was coined with the intent of
The American Journal of Human Genetics 10/2012; · 11.20 Impact Factor
[show abstract][hide abstract] ABSTRACT: To investigate the efficacy of etanercept in improving the symptoms and underlying inflammation in patients with tumor necrosis factor receptor-associated periodic syndrome (TRAPS).
Fifteen patients with TRAPS were enrolled in a prospective, open-label, dose-escalation study. Patients recorded attacks, symptom severity, and use of ancillary medications in a daily diary. Blood samples were collected during each period and measured for levels of acute-phase reactants. Between 7 years and 9 years after the conclusion of the initial study, patients completed a followup survey and were evaluated to determine the long-term outcome of etanercept treatment.
Etanercept treatment significantly attenuated the total symptom score and reduced the frequency of symptoms. Etanercept also reduced levels of acute-phase reactants, particularly during asymptomatic periods. During a 10-year followup period, patients continued to receive etanercept for a median of 3.3 years, with a number of patients switching to anti-interleukin-1β receptor therapy or not receiving biologic agents, most frequently citing injection site reactions and lack of efficacy as reasons for discontinuation. However, patients continuing to receive etanercept had reduced symptoms at followup.
Etanercept reduces symptoms and serum levels of inflammatory markers of TRAPS in a dose-dependent manner, but does not completely normalize symptoms or acute-phase reactant levels. Although long-term adherence to etanercept is poor, continuing to receive etanercept may provide continued symptomatic benefit.
[show abstract][hide abstract] ABSTRACT: Mendelian analysis of disorders of immune regulation can provide insight into molecular pathways associated with host defense and immune tolerance.
We identified three families with a dominantly inherited complex of cold-induced urticaria, antibody deficiency, and susceptibility to infection and autoimmunity. Immunophenotyping methods included flow cytometry, analysis of serum immunoglobulins and autoantibodies, lymphocyte stimulation, and enzymatic assays. Genetic studies included linkage analysis, targeted Sanger sequencing, and next-generation whole-genome sequencing.
Cold urticaria occurred in all affected subjects. Other, variable manifestations included atopy, granulomatous rash, autoimmune thyroiditis, the presence of antinuclear antibodies, sinopulmonary infections, and common variable immunodeficiency. Levels of serum IgM and IgA and circulating natural killer cells and class-switched memory B cells were reduced. Linkage analysis showed a 7-Mb candidate interval on chromosome 16q in one family, overlapping by 3.5 Mb a disease-associated haplotype in a smaller family. This interval includes PLCG2, encoding phospholipase Cγ(2) (PLCγ(2)), a signaling molecule expressed in B cells, natural killer cells, and mast cells. Sequencing of complementary DNA revealed heterozygous transcripts lacking exon 19 in two families and lacking exons 20 through 22 in a third family. Genomic sequencing identified three distinct in-frame deletions that cosegregated with disease. These deletions, located within a region encoding an autoinhibitory domain, result in protein products with constitutive phospholipase activity. PLCG2-expressing cells had diminished cellular signaling at 37°C but enhanced signaling at subphysiologic temperatures.
Genomic deletions in PLCG2 cause gain of PLCγ(2) function, leading to signaling abnormalities in multiple leukocyte subsets and a phenotype encompassing both excessive and deficient immune function. (Funded by the National Institutes of Health Intramural Research Programs and others.).
New England Journal of Medicine 01/2012; 366(4):330-8. · 51.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: The NLRP3 inflammasome complex is responsible for maturation of the pro-inflammatory cytokine, IL-1β. Mutations in NLRP3 are responsible for the cryopyrinopathies, a spectrum of conditions including neonatal-onset multisystem inflammatory disease (NOMID). While excessive production of IL-1β and systemic inflammation are common to all cryopyrinopathy disorders, skeletal abnormalities, prominently in the knees, and low bone mass are unique features of patients with NOMID. To gain insights into the mechanisms underlying skeletal abnormalities in NOMID, we generated knock-in mice globally expressing the D301N NLRP3 mutation (ortholog of D303N in human NLRP3). NOMID mice exhibit neutrophilia in blood and many tissues, including knee joints, and high levels of serum inflammatory mediators. They also exhibit growth retardation and severe postnatal osteopenia stemming at least in part from abnormally accelerated bone resorption, attended by increased osteoclastogenesis. Histologic analysis of knee joints revealed abnormal growth plates, with loss of chondrocytes and growth arrest in the central region of the epiphyses. Most strikingly, a tissue "spike" was observed in the mid-region of the growth plate in the long bones of all NOMID mice that may be the precursor to more severe deformations analogous to those observed in NOMID patients. These findings provide direct evidence linking a NOMID-associated NLRP3-activating mutation to abnormalities of postnatal skeletal growth and bone remodeling.
PLoS ONE 01/2012; 7(4):e35979. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Autoinflammatory diseases are characterized by seemingly unprovoked pathological activation of the innate immune system in the absence of autoantibodies or autoreactive T cells. Discovery of the causative mutations underlying several monogenic autoinflammatory diseases has identified key regulators of innate immune responses. Recent studies have highlighted the role of misfolding, oligomerization and abnormal trafficking of pathogenic mutant proteins in triggering autoinflammation, and suggest that more common rheumatic diseases may have an autoinflammatory component. This coincides with recent discoveries of new links between endoplasmic reticulum stress and inflammatory signalling pathways, which support the emerging view that autoinflammatory diseases may be due to pathological dysregulation of stress-sensing pathways that normally function in host defence.
[show abstract][hide abstract] ABSTRACT: To describe the genotypes, phenotypes, immunophenotypes, and treatments of PAPA syndrome (pyogenic sterile arthritis, pyoderma gangrenosum, and acne), a rare autoinflammatory disease, in 5 patients.
Clinical information was gathered from medical records and through interviews with 5 patients from 4 kindreds. PSTPIP1 (CD2BP1) exon 10 and exon 11 sequencing was performed in each patient. Neutrophil granule content and cytokine levels were determined in plasma and stimulated peripheral blood mononuclear cells (PBMCs) from patients and controls.
We identified 2 previously described PAPA syndrome-associated PSTPIP1 mutations, A230T and E250Q, and a novel change, E250K. Disease penetrance was incomplete, with variable expressivity. The cutaneous manifestations included pathergy, cystic acne, and pyoderma gangrenosum. Interleukin-1β (IL-1β) and circulating neutrophil granule enzyme levels were markedly elevated in patients compared to those in controls. PBMC stimulation studies demonstrated impaired production of IL-10 and enhanced production of granulocyte-macrophage colony-stimulating factor. Good resolution of pyoderma gangrenosum was achieved in 3 patients with tumor necrosis factor α (TNFα) blockade treatment.
This analysis of 5 patients demonstrates that mutations in PSTPIP1 are incompletely penetrant and variably expressed in the PAPA syndrome. Neutrophil granule proteins are markedly elevated ex vivo and in the plasma, and elevated levels might be compatible with a diagnosis of PAPA syndrome. TNFα blockade appears to be effective in treating the cutaneous manifestations of PAPA syndrome.
[show abstract][hide abstract] ABSTRACT: Missense mutations in the C-terminal B30.2 domain of pyrin cause familial Mediterranean fever (FMF), the most common Mendelian autoinflammatory disease. However, it remains controversial as to whether FMF is due to the loss of an inhibitor of inflammation or to the activity of a proinflammatory molecule. We generated both pyrin-deficient mice and "knockin" mice harboring mutant human B30.2 domains. Homozygous knockin, but not pyrin-deficient, mice exhibited spontaneous bone marrow-dependent inflammation similar to but more severe than human FMF. Caspase-1 was constitutively activated in knockin macrophages and active IL-1β was secreted when stimulated with lipopolysaccharide alone, which is also observed in FMF patients. The inflammatory phenotype of knockin mice was completely ablated by crossing with IL-1 receptor-deficient or adaptor molecule ASC-deficient mice, but not NLRP3-deficient mice. Thus, our data provide evidence for an ASC-dependent NLRP3-independent inflammasome in which gain-of-function pyrin mutations cause autoinflammatory disease.
[show abstract][hide abstract] ABSTRACT: The syndrome of periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) is the most common periodic fever disease in children. However, the pathogenesis is unknown. Using a systems biology approach we analyzed blood samples from PFAPA patients whose genetic testing excluded hereditary periodic fevers (HPFs), and from healthy children and pediatric HPF patients. Gene expression profiling could clearly distinguish PFAPA flares from asymptomatic intervals, HPF flares, and healthy controls. During PFAPA attacks, complement (C1QB, C2, SERPING1), IL-1-related (IL-1B, IL-1RN, CASP1, IL18RAP), and IFN-induced (AIM2, IP-10/CXCL10) genes were significantly overexpressed, but T cell-associated transcripts (CD3, CD8B) were down-regulated. On the protein level, PFAPA flares were accompanied by significantly increased serum levels of chemokines for activated T lymphocytes (IP-10/CXCL10, MIG/CXCL9), G-CSF, and proinflammatory cytokines (IL-18, IL-6). PFAPA flares also manifested a relative lymphopenia. Activated CD4(+)/CD25(+) T-lymphocyte counts correlated negatively with serum concentrations of IP-10/CXCL10, whereas CD4(+)/HLA-DR(+) T lymphocyte counts correlated positively with serum concentrations of the counterregulatory IL-1 receptor antagonist. Based on the evidence for IL-1β activation in PFAPA flares, we treated five PFAPA patients with a recombinant IL-1 receptor antagonist. All patients showed a prompt clinical and IP-10/CXCL10 response. Our data suggest an environmentally triggered activation of complement and IL-1β/-18 during PFAPA flares, with induction of Th1-chemokines and subsequent retention of activated T cells in peripheral tissues. IL-1 inhibition may thus be beneficial for treatment of PFAPA attacks, with IP-10/CXCL10 serving as a potential biomarker.
Proceedings of the National Academy of Sciences 04/2011; 108(17):7148-53. · 9.74 Impact Factor