Adult autoinflammatory disease frequency and our diagnostic experience in an adult autoinflammatory clinic

Yao Syndrome: An Overview of Genotypic Associations, Clinical Manifestations, Diagnosis, and Treatment

BACKGROUND

Yao syndrome (YAOS) is a rare systemic autoinflammatory disorder (AID) of the innate immune system. It was recently categorized as genetically transitional disease (GTD) and is associated with NOD2 variants located at multiple NOD2 gene loci. Unlike most other periodic fever syndromes, the estimated disease prevalence is 1-10/100,000 with a predominance for females and white adult population. In this review, we aimed to provide a detailed analysis of different aspects of this syndrome to help better understand the underlying pathogenesis and incorporate the current evidence-based medicine published to diagnose and manage these patients.

SUMMARY

We conducted literature search on YAOS from 2011 to 2024 using PubMed, Embase, and Scopus databases. Thirty-two studies were included in our narrative review. A descriptive analysis was performed of both Yao and non-Yao authored records to embrace the syndrome reported from all investigators and assess differences and similarities. The most reported gene variant is the homozygous IVS8+158 followed by compound heterozygous IVS8+158 and R702W. Mean age of disease onset is between 36 and 42 years. The mean age of disease diagnosis is between 40 and 45 years with a variable disease duration. Fever is the most commonly reported symptom followed by musculoskeletal, gastrointestinal symptoms and dermatitis. On laboratory workup, patients have elevated levels of erythrocyte sedimentation rate, C-reactive protein, and serum ferritin with negative autoantibody workup. Arthritic symptoms in YAOS patients have a positive response to sulfasalazine and glucocorticoids, while nonsteroidal anti-inflammatory drugs and colchicine produce minimal response. Anti-IL1 and anti-IL6 agents (canakinumab, anakinra, and tocilizumab) are effective treatment modalities.

KEY MESSAGES

The evolving concept and acceptance of GTD will hopefully further our understanding about this SAID and similar disorders. We suggest developing a registry of patients with YAOS to keep track of expanding data on this subject. It is important to understand various aspects of YAOS including genetic and environmental factors, differential diagnosis, clinical manifestations, laboratory findings, and treatment options available to diagnose and manage these patients appropriately and timely.

Expanding clinical characteristics and genotypic profiling of Yao syndrome in Chinese patients

Objectives

Yao syndrome (YAOS, OMIM# 617321) is a kind of systemic autoinflammatory diseases (SAIDs) linked to the nucleotide-binding oligomerization domain containing 2 (NOD2). Clinical reports of YAOS in China are sparse. Herein, we reported the largest YAOS cohort of Chinese patients to expand the understanding of its phenotype, genotype, and therapeutic responses.

Methods

This study enrolled 15 adult patients diagnosed with YAOS at Peking Union Medical College Hospital from April 2015 to May 2024. Whole-exome sequencing was performed on all patients. Clinical data, genetic variations, and treatment responses were documented and compared with a Caucasian cohort.

Results

The mean age of disease onset was 35 ± 17 years old. The most common clinical manifestations included recurrent high-grade fever (100%), gastrointestinal symptoms (73.3%), arthralgia/arthritis, fatigue, myalgia, and lower extremity swelling (46.7%). All patients exhibited elevated acute-phase reactants during episodes. 12 heterozygous NOD2 variants were identified, with Q902K in 4 patients, R471C in 3, and variants c.-14C>T, A110T, S127L, R311W, A432V, Y514H, R541P, A661P, K818Q, A886V each found in individual patients. 90% of the patients responded well to glucocorticoids, and 55.6% to sulfasalazine. 66.7% of patients who received TNF inhibitors achieved complete resolution of symptoms. Additionally, one patient each responded favorably to canakinumab and tocilizumab. Compared to the Caucasian cohort, our cohort exhibited a more balanced gender ratio and a higher proportion of recurrent fever, proteinuria/hematuria as well as more frequent leukocytosis, elevated acute phase reactants, and anemia. Lower proportions of arthralgia/arthritis, skin rashes, headaches, and sicca-like symptoms were noted in our cohort. Moreover, a higher proportion of patients in our cohort showed a good response to TNF inhibitors.

Conclusion

Chinese patients with YAOS had more pronounced inflammatory manifestations compared to the Caucasian cohort. Variants c.-14C>T, A110T, S127L, A661P, K818Q, A886V, R471C, and A432V were identified as novel NOD2 variants in YAOS. TNF, IL-6, and IL-1 inhibitors are the promising treatment options. These findings expand the clinical spectrum, genetic profile, and treatment efficacy of YAOS, underscoring the need for heightened awareness of this disease in diverse populations.

Amyopathic dermatomyositis may be on the spectrum of autoinflammatory disease: A clinical review

Systemic autoinflammatory diseases (SAIDs) are distinct from autoimmune diseases. The former primarily results from abnormal innate immune response and genetic testing is crucial for disease diagnosis. Similar cutaneous involvement is a main feature for both SAID and dermatomyositis (DM), so they can be confused with each other. A literature search of PubMed and MEDLINE was conducted for relevant articles. The similarities and differences between these two types of diseases were analyzed. We found phenotypic similarities between these two types of disorders. Accumulating data supports a major role of the innate immune system and a similar cytokine profile. Molecular testing using an autoinflammatory disease gene panel may help identify SAID patients from the DM population and may offer therapeutic benefit using interleukin-1 (IL-1) inhibitors. A subset of DM, notably amyopathic dermatomyositis in the absence of autoantibodies may be on the spectrum of autoinflammatory disease.

The expanding clinical spectrum of autoinflammatory diseases with NOD2 variants: a case series and literature review

Objective

To assess the impact conferred by NOD2 variants on the clinical spectrum of patients with systemic autoinflammatory diseases (SAIDs) in Greece.

Methods

Consecutive patients (n=167) with confirmed SAIDs who underwent screening by next generation sequencing (NGS) targeting 26 SAID-associated genes, and carried at least one NOD2 gene variant, were retrospectively studied. The demographic, clinical and laboratory parameters were recorded.

Results

In total, 24 rare NOD2 variants in 23/167 patients (14%) were detected. Notably, 18 patients had at least one co-existing variant in 13 genes other than NOD2. Nine patients had juvenile- and 14 adult-onset disease. All patients presented with symptoms potentially induced by the NOD2 variants. In particular, the candidate clinical diagnosis was Yao syndrome (YAOS) in 12 patients (7% of the whole SAID cohort). The clinical spectrum of patients with YAOS (mean episode duration 8 days) was fever (n=12/12), articular symptoms (n=8), gastrointestinal symptoms (n=7; abdominal pain/bloating in 7; diarrhea in 4; oral ulcers in 3), serositis (n=7), and rash (n=5), while the inflammatory markers were elevated in all but one patient. Most of these patients showed a poor response to nonsteroidal anti-inflammatory drugs (n=7/9), colchicine (n=6/8) and/or anti-TNF treatment (n=3/4), while a complete response was observed in 6/10 patients receiving steroids and 3/5 on anti-IL1 treatment. Another 8 patients were diagnosed with either FMF (n=6) or PFAPA syndrome (n=2) presenting with prominent diarrhea (n=7), oral ulcers (n=2), periorbital swelling and sicca-like symptoms (n=1), or maculopapular rash (n=1). One patient had a clinically undefined SAID, albeit characterized by oral ulcers and diarrhea. Finally, one patient presented with chronic relapsing urticaria with periorbital edema and inflammatory markers, and another one had a Crohn-like syndrome with good response to anti-IL-1 but refractory to anti-TNF treatment.

Conclusion

NOD2 variants were detected in 1 out of 7 SAID patients and seem to have an impact on disease phenotype and treatment response. Further studies should validate combined molecular and clinical data to better understand these distinct nosological entities.

Systematic genetic analysis of pediatric patients with autoinflammatory diseases

Monogenic autoinflammatory diseases (AID) encompass a growing group of inborn errors of the innate immune system causing unprovoked or exaggerated systemic inflammation. Diagnosis of monogenic AID requires an accurate description of the patients' phenotype, and the identification of highly penetrant genetic variants in single genes is pivotal. We performed whole exome sequencing (WES) of 125 pediatric patients with suspected monogenic AID in a routine genetic diagnostic setting. Datasets were analyzed in a step-wise approach to identify the most feasible diagnostic strategy. First, we analyzed a virtual gene panel including 13 genes associated with known AID and, if no genetic diagnosis was established, we then analyzed a virtual panel including 542 genes published by the International Union of Immunological Societies associated including all known inborn error of immunity (IEI). Subsequently, WES data was analyzed without pre-filtering for known AID/IEI genes. Analyzing 13 genes yielded a definite diagnosis in 16.0% (n = 20). The diagnostic yield was increased by analyzing 542 genes to 20.8% (n = 26). Importantly, expanding the analysis to WES data did not increase the diagnostic yield in our cohort, neither in single WES analysis, nor in trio-WES analysis. The study highlights that the cost- and time-saving analysis of virtual gene panels is sufficient to rapidly confirm the differential diagnosis in pediatric patients with AID. WES data or trio-WES data analysis as a first-tier diagnostic analysis in patients with suspected monogenic AID is of limited benefit.

New insights on multigenic autoinflammatory diseases

Autoinflammatory diseases are disorders of the innate immune system, which can be either monogenic due to a specific genetic mutation or complex multigenic due to the involvement of multiple genes. The aim of this review is to explore and summarize the recent advances in pathogenesis, diagnosis, and management of genetically complex autoinflammatory diseases, such as Schnitzler's syndrome; adult-onset Still's disease; synovitis, acne, pustulosis, hyperostosis, osteitis syndrome/chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis; Adamantiades-Behçet's disease; Yao syndrome; and periodic fever with aphthous stomatitis, pharyngitis, and adenitis syndrome. The PubMed database was screened for relevant articles using free text words and specific search strings. The search was limited to English-language articles, reporting the results of studies in humans, published through March 2021. Evidence from literature suggest that these rare multigenic autoinflammatory diseases can present with different clinical features and the diagnosis of these diseases can be challenging due to a combination of nonspecific manifestations that can be seen in a variety of other conditions. Diagnostic delays and disease complications may occur due to low disease awareness and the lack of pathognomonic markers. The pathogeneses of these diseases are complex and in some cases precise pathogenesis is not clearly understood. Conventional treatments are commonly used for the management of these conditions, but biologics have shown promising results. Biologics targeting proinflammatory cytokines including IL-1, IL-6, TNF-α, IL-17A and IL-18 have been shown to ameliorate signs and symptoms of different multigenic autoinflammatory diseases.

Systemic autoinflammatory disease in adults

Systemic autoinflammatory disorders comprise an expanding group of rare conditions. They are mediated by dysfunction of the innate immune system and share a core of phenotypic manifestations including recurrent attacks of fever, cutaneous signs, chest or abdominal pain, lymphadenopathy, vasculopathy, and musculoskeletal symptoms. Diagnosis is often established in childhood, but a growing number of adult patients are being recognized with systemic autoinflammatory disorders, including adult-onset disease. In this review, we provide a concise update on the pathophysiology, clinical presentation, and diagnostic approach of systemic autoinflammatory disorders with an emphasis on the adult patient population. Despite the recent advances in genetic testing, the diagnosis of autoinflammatory disease in adult patients is often based on a thorough knowledge of the clinical phenotype. Becoming acquainted with the clinical features of these rare disorders may assist in developing a high index of suspicion for autoinflammatory disease in patients presenting with unexplained episodes of fever or inflammation.

Monogenic autoinflammatory disorders: beyond the periodic fever

The past two decades have seen an exponential increase in the number of monogenic autoinflammatory disorders described, coinciding with improved genetic sequencing techniques. This group of disorders has evolved to be heterogeneous and certainly more complex than the original four 'periodic fever syndromes' caused by innate immune over-activation. This review aims to provide an update on the classic periodic fever syndromes as well as introducing the broadening spectrum of clinical features seen in more recently described conditions.

The clinical phenotype and genotype of NLRP12-autoinflammatory disease: a Chinese case series with literature review

BACKGROUND

The nucleotide-binding oligomerization domain-like receptor protein 12 (NLRP12)-autoinflammatory disorder (NLRP12-AD) is a rare autoinflammatory disease characterized by recurrent fever, rash as well as musculoskeletal symptoms, which is rarely reported in Asian populations.

METHODS

Three cases of NLRP12-AD presented to our hospital were studied after parental consents were obtained. Clinical presentations were recorded on a standardized case report form. Mutations of NLRP12 were detected by primary immunodeficiency disease panels and further examined by Sanger sequencing. PubMed literature search for relevant studies of systemic autoinflammatory disorders, especially NLRP12-AD between January, 2000 and January, 2019 was carried and the clinical data were summarized. Comparisons were made between groups in terms of onset age and of ethnicity.

RESULTS

All our patients presented with fever, rash and arthritis/arthralgia, and sensorineural as well as sensorineural deafness (1/3), uveitis (1/3), abdominal pain (1/3), and myalgia (1/3). Two novel mutation variations, p.W581X and p.L558R, are reported here. In addition, we also found that two patients inherited the mutated alleles from their healthy parents, and this may be evidence of haploinsufficiency.

CONCLUSIONS

Although the genotypes are similar, the clinical manifestations between Chinese patients and Western patients vary thus highlighting the possible influence of ethnic and environmental factors. On the other hand, some genetic mutations may lead to specific phenotype, as we have found a high prevalence of sensorineural hearing loss among p.R284X patients.

Is gene panel sequencing more efficient than clinical-based gene sequencing to diagnose autoinflammatory diseases? A randomized study

The aim of this study was to compare the effectiveness of the gene-panel next-generation sequencing (NGS) strategy versus the clinical-based gene Sanger sequencing for the genetic diagnosis of autoinflammatory diseases (AIDs). Secondary goals were to describe the gene and mutation distribution in AID patients and to evaluate the impact of the genetic report on the patient's medical care and treatment. Patients with AID symptoms were enrolled prospectively and randomized to two arms, NGS (n = 99) (32-55 genes) and Sanger sequencing (n = 197) (one to four genes). Genotypes were classified as 'consistent/confirmatory', 'uncertain significance' or 'non-contributory'. The proportion of patients with pathogenic genotypes concordant with the AID phenotype (consistent/confirmatory) was significantly higher with NGS than Sanger sequencing [10 of 99 (10·1%) versus eight of 197 (4·1%)]. MEFV, ADA2 and MVK were the most represented genes with a consistent/confirmed genotype, whereas MEFV, NLRP3, NOD2 and TNFRSF1A were found in the 'uncertain significance' genotypes. Six months after the genetic report was sent, 54 of 128 (42·2%) patients had received effective treatment for their symptoms; 13 of 128 (10·2%) had started treatment after the genetic study. For 59 of 128 (46%) patients, the results had an impact on their overall care, independent of sequencing group and diagnostic conclusion. Targeted NGS improved the diagnosis and global care of patients with AIDs.

Clinical Features at Onset and Genetic Characterization of Pediatric and Adult Patients with TNF-α Receptor-Associated Periodic Syndrome (TRAPS): A Series of 80 Cases from the AIDA Network

This study explores demographic, clinical, and therapeutic features of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) in a cohort of 80 patients recruited from 19 Italian referral Centers. Patients' data were collected retrospectively and then analyzed according to age groups (disease onset before or after 16 years) and genotype (high penetrance (HP) and low penetrance (LP) TNFRSF1A gene variants). Pediatric- and adult-onset were reported, respectively, in 44 and 36 patients; HP and LP variants were found, respectively, in 32 and 44 cases. A positive family history for recurrent fever was reported more frequently in the pediatric group than in the adult group (p < 0.05). With reference to clinical features during attacks, pericarditis and myalgia were reported more frequently in the context of adult-onset disease than in the pediatric age (with p < 0.01 and p < 0.05, respectively), while abdominal pain was present in 84% of children and in 25% of adults (p < 0.01). Abdominal pain was significantly associated also to the presence of HP mutations (p < 0.01), while oral aphthosis was more frequently found in the LP variant group (p < 0.05). Systemic amyloidosis occurred in 25% of subjects carrying HP variants. As concerns laboratory features, HP mutations were significantly associated to higher ESR values (p < 0.01) and to the persistence of steadily elevated inflammatory markers during asymptomatic periods (p < 0.05). The presence of mutations involving a cysteine residue, abdominal pain, and lymphadenopathy during flares significantly correlated with the risk of developing amyloidosis and renal impairment. Conversely, the administration of colchicine negatively correlated to the development of pathologic proteinuria (p < 0.05). Both NSAIDs and colchicine were used as monotherapy more frequently in the LP group compared to the HP group (p < 0.01). Biologic agents were prescribed to 49 (61%) patients; R92Q subjects were more frequently on NSAIDs monotherapy than other patients (p < 0.01); nevertheless, they required biologic therapy in 53.1% of cases. At disease onset, the latest classification criteria for TRAPS were fulfilled by 64/80 (80%) patients (clinical plus genetic items) and 46/80 (57.5%) patients (clinical items only). No statistically significant differences were found in the sensitivity of the classification criteria according to age at onset and according to genotype (p < 0.05). This study describes one of the widest cohorts of TRAPS patients in the literature, suggesting that the clinical expression of this syndrome is more influenced by the penetrance of the mutation rather than by the age at onset itself. Given the high phenotypic heterogeneity of the disease, a definite diagnosis should rely on both accurate working clinical assessment and complementary genotype.

Genetic diagnosis of autoinflammatory disease patients using clinical exome sequencing

Autoinflammatory diseases comprise a wide range of syndromes caused by dysregulation of the innate immune response. They are difficult to diagnose due to their phenotypic heterogeneity and variable expressivity. Thus, the genetic origin of the disease remains undetermined for an important proportion of patients. We aim to identify causal genetic variants in patients with suspected autoinflammatory disease and to test the advantages and limitations of the clinical exome gene panels for molecular diagnosis. Twenty-two unrelated patients with clinical features of autoinflammatory diseases were analyzed using clinical exome sequencing (~4800 genes), followed by bioinformatic analyses to detect likely pathogenic variants. By integrating genetic and clinical information, we found a likely causative heterozygous genetic variant in NFKBIA (p.D31N) in a North-African patient with a clinical picture resembling the deficiency of interleukin-1 receptor antagonist, and a heterozygous variant in DNASE2 (p.G322D) in a Spanish patient with a suspected lupus-like monogenic disorder. We also found variants likely to increase the susceptibility to autoinflammatory diseases in three additional Spanish patients: one with an initial diagnosis of juvenile idiopathic arthritis who carries two heterozygous UNC13D variants (p.R727Q and p.A59T), and two with early-onset inflammatory bowel disease harbouring NOD2 variants (p.L221R and p.A728V respectively). Our results show a similar proportion of molecular diagnosis to other studies using whole exome or targeted resequencing in primary immunodeficiencies. Thus, despite its main limitation of not including all candidate genes, clinical exome targeted sequencing can be an appropriate approach to detect likely causative variants in autoinflammatory diseases.

Autoinflammatory disease with focus on NOD2-associated disease in the era of genomic medicine

Systemic autoinflammatory diseases (SAIDs) represent a spectrum of genetically heterogeneous inflammatory disorders. Some SAID-associated genes are located in chromosome 16, including familial Mediterranean fever gene (MEFV) and nucleotide-binding oligomerization domain 2 [NOD2] gene that are linked to Crohn's disease, Blau syndrome, and Yao syndrome. These disorders share overlapping clinical phenotypes, and genotyping is diagnostically helpful and distinctive. Using next generation sequencing in SAIDs, digenic variants or combinations of more genetic variants in different genes can be detected, and they may be related to the MEFV and NOD2 genes. These variants may contribute to heterogeneous phenotypes in an individual, complicating the diagnosis and therapy. An awareness of the clinical significance of the digenic or combined gene variants is important in the era of genomic medicine.

Diagnostic utility of a targeted next-generation sequencing gene panel in the clinical suspicion of systemic autoinflammatory diseases: a multi-center study

Systemic autoinflammatory diseases (sAIDs) are a heterogeneous group of disorders, having monogenic inherited forms with overlapping clinical manifestations. More than half of patients do not carry any pathogenic variant in formerly associated disease genes. Here, we report a cross-sectional study on targeted Next-Generation Sequencing (NGS) screening in patients with suspected sAIDs to determine the diagnostic utility of genetic screening. Fifteen autoinflammation/immune-related genes (ADA2-CARD14-IL10RA-LPIN2-MEFV-MVK-NLRC4-NLRP12-NLRP3-NOD2-PLCG2-PSTPIP1-SLC29A3-TMEM173-TNFRSF1A) were used to screen 196 subjects from adult/pediatric clinics, each with an initial clinical suspicion of one or more sAID diagnosis with the exclusion of typical familial Mediterranean fever (FMF) patients. Following the genetic screening, 140 patients (71.4%) were clinically followed-up and re-evaluated. Fifty rare variants in 41 patients (20.9%) were classified as pathogenic or likely pathogenic and 32 of those variants were located on the MEFV gene. We detected pathogenic or likely pathogenic variants compatible with the final diagnoses and inheritance patterns in 14/140 (10%) of patients for the following sAIDs: familial Mediterranean fever (n = 7), deficiency of adenosine deaminase 2 (n = 2), mevalonate kinase deficiency (n = 2), Muckle-Wells syndrome (n = 1), Majeed syndrome (n = 1), and STING-associated vasculopathy with onset in infancy (n = 1). Targeted NGS panels have impact on diagnosing rare monogenic sAIDs for a group of patients. We suggest that MEFV gene screening should be first-tier genetic testing especially in regions with high carrier rates. Clinical utility of multi-gene testing in sAIDs was as low as expected, but extensive genome-wide familial analyses in combination with exome screening would enlighten additional genetic factors causing disease.

Diagnosis and treatment of autoinflammatory diseases in adults: a clinical approach from rheumatologists

Autoinflammatory diseases are characterized by recurrent systemic inflammation due to dysfunction of the innate immune system, and they are originally the hereditary recurrent fever syndromes that develop in early childhood. Many cases are thus diagnosed in the pediatric field, but there are many cases that are not diagnosed until adulthood, including adult-onset cases. Accordingly, not only pediatricians but also rheumatologists and primary care physicians play a major role in the diagnosis and treatment of autoinflammatory diseases. Broad non-hereditary autoinflammatory diseases such as adult-onset Still disease and Behcet's disease are also often encountered in routine internal medicine practice. With recent developments in genetic testing, the conditions of patients who have been diagnosed and treated as having fevers of unknown etiology have been increasingly classified as autoinflammatory diseases. Regarding treatment in Japan, biological agents (such as canakinumab) that inhibit IL-1β are now administered to patients with autoinflammatory diseases. In this review, we introduce an approach from rheumatologists based on diagnoses and treatment of 'classical" autoinflammatory diseases in adults, focusing on familial Mediterranean fever, which has a high frequency in adults.

A delayed diagnosis: recurrent fever and beta thalassaemia

Familial Mediterranean fever and beta-thalassaemia are two genetic disorders, with a largely common geographical distribution. However, they have not much else in common, as the first is an autoinflammatory disorder, while the other is a haemoglobinopathy. We describe a patient with known beta-thalassaemia intermedia who presented with recurrent fevers and he was diagnosed with familial Mediterranean fever 2 years later. We discuss whether there is an association between the two disorders and the cognitive biases that lead to the delay in the diagnosis of familial Mediterranean fever.

Alterations in nucleotide-binding oligomerization domain-2 expression, pathway activation, and cytokine production in Yao syndrome

Yao syndrome (YAOS) is a systemic autoinflammatory disease (SAID), formerly termed nucleotide-binding oligomerization domain-2 (NOD2)-associated autoinflammatory disease. Due to the recent identification of YAOS, the molecular mechanisms underlying its disease pathogenesis are unclear. With specific NOD2 variants as characteristic genotypic features of YAOS, our study examined NOD2 expression, transcript splicing, signaling pathway activation, and cytokine profiles in peripheral blood mononuclear cells (PBMCs) from 10 YAOS patients and six healthy individuals. All participants were genotyped for NOD2 variants; all YAOS patients were heterozygous for the NOD2 IVS8⁺¹⁵⁸ variant (IVS8⁺¹⁵⁸) and four patients also carried a concurrent NOD2 R702W variant (IVS8⁺¹⁵⁸/R702W haplotype). Resembling other SAIDs, plasma levels of TNFα, IL-1β, IL-6, IFNγ, and S100A12 were unaltered in YAOS patients. Intron-8 splicing of NOD2 transcripts was unaffected by carriage of NOD2 IVS8⁺¹⁵⁸. However, NOD2 transcript level and basal p38 mitogen-activated protein kinase (MAPK) activity were significantly elevated in PBMCs from IVS8⁺¹⁵⁸ YAOS patients. Moreover, these patients' cells had elevated basal IL-6 secretion that was enhanced by muramyl dipeptide (MDP) stimulation. Tocilizumab treatment of a YAOS IVS8⁺¹⁵⁸ patient resulted in marked clinical improvement. In contrast, MDP-stimulated NF-κB activity was uniquely suppressed in haplotype IVS8⁺¹⁵⁸/R702W patients, as was TNFα secretion. Our study demonstrates for the first time that NOD2 expression and pathway activation are aberrant in YAOS, and specific NOD2 genotypes result in distinct NOD2 expression and cytokine profiles. These findings may also help select therapeutic strategies in the future.

A Systematic Analysis of Treatment and Outcomes of NOD2-Associated Autoinflammatory Disease

OBJECTIVES

Yao syndrome, formerly named NOD2-associated autoinflammatory disease, is a periodic disease characterized by fever, dermatitis, polyarthritis/leg swelling, and gastrointestinal and sicca-like symptoms associated with specific NOD2 sequence variants. Our aim was to evaluate the treatment and outcomes of the disease.

METHODS

A total of 52 adult patients with autoinflammatory disease phenotype were diagnosed with Yao syndrome and enrolled at the Cleveland Clinic between November 2009 and May 2015. All patients were genotyped for the NOD2 variants, and systematically studied for treatment outcomes.

RESULTS

Among the 52 Yao syndrome patients, all were white, and 72% were women. The mean age at diagnosis was 38.0 ± 12.0 years, and the disease duration was 8.8 ± 5.8 years. In the multi-organ disease, more common and typical manifestations were recurrent dermatitis and inflammatory arthritis with or without distal leg swelling besides recurrent fever. It was genotypically associated with the NOD2 IVS8⁺¹⁵⁸ or R702W. Therapeutically, glucocorticoids markedly decreased the disease severity and duration of flares in 19 patients (36.6%), sulfasalazine treatment achieved a significant symptomatic improvement in 22 (42%) patients, and 3 patients received canakinumab or tocilizumab with benefits. Prognostically, 13% of the 52 patients had somewhat physical impairment, and there was no mortality during the follow-up. Associated comorbidities were fibromyalgia, asthma, renal stones, and ventricular hypertrophy.

CONCLUSIONS

As a systemic disease, Yao syndrome uncommonly affects the solid internal organs, but it can be complicated with chronic pain syndrome and even disability. Glucocorticoids or sulfasalazine may be considered as the first-line treatment option, and interleukin (IL)-1/IL-6 inhibitors may be tried for refractory cases. The potential associations between certain comorbidities and Yao syndrome deserve further study.

Autoinflammatory diseases in adults. Clinical characteristics and prognostic implications

Autoinflammatory diseases are clinical conditions with inflammatory manifestations that present in a periodic or persistent manner and are caused by acquired or hereditary disorders of the innate immune response. In general, these diseases are more common in childhood, but cases have been reported in adults and are therefore important for all specialists. There are few references on these diseases in adults due to their low prevalence and underdiagnosis. The aim of this study is to review the scientific literature on these disorders to systematise their clinical, prognostic and treatment response characteristics in adults.

NLRP12 autoinflammatory disease: a Chinese case series and literature review

As one of the systemic autoinflammatory diseases (SAIDs), the nucleotide-binding oligomerization domain-like receptor protein (NLRP)12 autoinflammatory disease (NLRP12-AD) is an autosomal dominant disorder associated with NLRP12 mutation. SAIDs have been hardly reported in the Chinese population, and NLRP12-AD has been reported only in Caucasians. We report the first case series of NLRP12-AD in the Chinese population coupled with literature review. Three Han Chinese adult patients with clinical phenotype suggestive of NLRP12-AD carrying NLRP12 variants were treated by the authors in 2015. Their phenotype and genotype were carefully studied. A PubMed search for SAIDs was conducted between January, 1990 and January, 2016, and we focused on NLRP12-AD. All three adult patients developed periodic disease in adulthood. They presented with recurrent fever (n = 3), polyarthralgia (n = 3), myalgia (n = 3), urticaria (n = 2), lymphadenopathy (n = 2), and erythema nodosa (n = 1). All patients carry the NLRP12 mutation F402L. Based upon our analysis of a total of 26 patients with NLRP12-AD in the literature, both familial and sporadic cases were equally reported and late-onset cases accounted for 28 %. NLRP12-AD patients typically present with periodic fever, urticaria-like rash, arthralgia/arthritis, myalgia, and lymphadenopathy. Genotyping identifies the NLRP12 gene mutations, notably F402L (55 %). Relative to the literature reports, our patients had the similar phenotypic and genotypic features. Patients with NLRP12-AD usually respond to glucocorticoid therapy. Our report is the first to confirm the presence of NLRP12-AD in the Chinese population. It highlights the importance of screening NLRP12 in patients with unexplained periodic fever syndrome.