Six-month safety and effectiveness of tofacitinib in patients with rheumatoid arthritis in Japan: Interim analysis of post-marketing surveillance.

OBJECTIVES: We evaluated the real-world safety/effectiveness of tofacitinib, an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA), in patients with RA in Japan registered in a post-marketing surveillance study. METHODS: This interim analysis included data from July 2013 to December 2018. Adverse events (AEs), serious AEs (SAEs), Simplified Disease Activity Index (SDAI)/Clinical Disease Activity Index (CDAI)/Disease Activity Score in 28 joints, erythrocyte sedimentation rate [DAS28-4(ESR)] scores, and rates of SDAI/CDAI/DAS28-4(ESR)-defined remission and low disease activity were analysed using 6 months of data. Risk factors for serious infections were assessed by multivariable analyses. RESULTS: Safety and disease activity were evaluated in 6866 and 6649 patients, respectively. Overall, 32.73%/7.37% of patients reported AEs/SAEs. Clinically important AEs with tofacitinib included serious infections/infestations [3.13% of patients; incidence rate (IR; patients with events) 6.91/100 patient-years (PY)], herpes zoster (3.63%; IR 8.02/100 PY), and malignancies (0.68%; IR 1.45/100 PY). SDAI/CDAI/DAS28-4(ESR) scores and remission/low disease activity rates improved over 6 months. Male sex, older age, Steinbrocker's stage IV, history of infection, and diabetes mellitus at baseline were independent risk factors for serious infection. CONCLUSIONS: In patients with RA receiving tofacitinib in Japan, safety was consistent with the reported profile, and disease activity improved over 6 months. STUDY IDENTIFIER: NCT01932372.

Long-term efficacy and safety of canakinumab in the treatment of systemic juvenile idiopathic arthritis in Japanese patients: Results from an open-label Phase III study.

OBJECTIVES: The objective of the study was to report the efficacy and safety of canakinumab treatment in Japanese patients with systemic juvenile idiopathic arthritis (sJIA) over a 48-week study period. METHODS: Patients were administered canakinumab 4 mg/kg (maximum dose 300 mg) every 4 weeks, with no dose adjustments. The key outcome measures included adapted American College of Rheumatology paediatric (aACR pedi) 30/50/70/90/100 response, proportion of patients with inactive disease, and corticosteroid (CS) tapering. RESULTS: In total, 16/19 (84.2%) patients received canakinumab for ≥96 weeks reaching end-of-study (EOS) visit without premature discontinuation. Regardless of the level of joint involvement at baseline, high aACR pedi responses were observed throughout the study; at the EOS, aACR pedi 90/100 response rates were 84.2%/63.2%, respectively. The proportion of patients who successfully tapered CSs at EOS was 66.7% (12/18), of which 10 patients were steroid-free. The most common adverse events were infections (238.3 events/100 patient-years). Serious adverse events were observed in 52.6%. The event (n=1) adjudicated as possible macrophage activation syndrome was preceded by sJIA flare. No deaths were reported. CONCLUSIONS: Canakinumab treatment resulted in a sustained treatment response in sJIA patients over 48 weeks and was associated with CS tapering in majority of patients. No new safety findings were reported.

Rheumatoid factor value for determining the first biologic agent to use for non-systemic juvenile idiopathic arthritis.

OBJECTIVES: Currently, no indicators on which biologic disease-modifying anti-rheumatic drugs (bDMARDs) should be used first for juvenile idiopathic arthritis (JIA) have been established. Thus, this study aimed to determine the useful biomarkers in JIA to enable the best selection of the first bDMARDs without primary failure. METHODS: This retrospective study used data of patients examined for JIA between 2015 and 2021 at Kagoshima University Hospital in Japan. RESULTS: Altogether, 67 cases of non-systemic JIA were analyzed, excluding cases that had been treated for <6 months. Of the 67 cases, 52 were treated with bDMARDs and all rheumatoid factor (RF)+ types (32 cases) were treated with bDMARDs. Eleven cases (31.4&) (all were RF+ types and used anti-tumor necrosis factor (TNF)α agents) switched to other bDMARDs because of primary failure, and nine cases had secondary failure (6;anti-TNF, 3;anti-Interleukin-6). A significant difference in pre-treatment RF values (177.9 vs 25.7 IU/ml, p = 0.002) and presence (Odds Ratio 1.952,p = 0.004) were observed between the primary failure group and effective group. CONCLUSIONS: RF+ JIA required bDMARDs with high probability. JIA with high titre of RF tends to be refractory to anti-TNFα agents. Tocilizumab or abatacept could be a first-choice bDMARD in such cases.

Potential Benefits of TNF Targeting Therapy in Blau Syndrome, a NOD2-Associated Systemic Autoinflammatory Granulomatosis.

Blau syndrome is a systemic autoinflammatory granulomatous disease caused by mutations in the nucleotide-binding oligomerization domain 2 (NOD2) gene. NOD2 is an intracellular pathogen recognition receptor. Upon binding to muramyl dipeptide (MDP), NOD2 activates the NF-κB pathway, leading to the upregulation of proinflammatory cytokines. Clinical manifestations of Blau syndrome appear in patients before the age of four. Skin manifestations resolve spontaneously in some cases; however, joint and eye manifestations are progressive, and lead to serious complications, such as joint contracture and blindness. Currently, there is no specific curative treatment for the disease. Administration of high-dose oral steroids can improve clinical manifestations; however, treatments is difficult to maintain due to the severity of the side effects, especially in children. While several new therapies have been reported, including JAK inhibitors, anti-IL-6 and anti-IL-1 therapies, anti-TNF therapy plays a central role in the treatment of Blau syndrome. We recently performed an ex vivo study, using peripheral blood and induced pluripotent stem cells from patients. This study demonstrated that abnormal cytokine expression in macrophages from untreated patients requires IFNγ stimulation, and that anti-TNF treatment corrects the abnormalities associated with Blau syndrome, even in the presence of IFNγ. Therefore, although the molecular mechanisms by which the genetic mutations in NOD2 lead to granuloma formation remain unclear, it is possible that prior exposure to TNFα combined with IFNγ stimulation may provide the impetus for the clinical manifestations of Blau syndrome.

Anti-TNF treatment corrects IFN-γ-dependent proinflammatory signatures in Blau syndrome patient-derived macrophages.

BACKGROUND: Blau syndrome (BS) is an autoinflammatory disease associated with mutations in nucleotide-binding oligomerization domain 2. Although treatments with anti-TNF agents have been reported to be effective, the underlying molecular mechanisms remain unclear. OBJECTIVE: We aimed to elucidate the mechanisms of autoinflammation in patients with BS and to clarify how anti-TNF treatment controls the disease phenotype at the cellular level in clinical samples. METHODS: Macrophages were differentiated from monocytes of 7 BS patients, and global transcriptional profiles of 5 patients were analyzed with or without IFN-γ stimulation. Macrophages were also generated from BS-specific induced pluripotent stem cells (iPSCs), and their transcriptome was examined for comparison. RESULTS: Aberrant inflammatory responses were observed upon IFN-γ stimulation in macrophages from untreated BS patients, but not in those from patients treated with anti-TNF. iPSC-derived macrophages carrying a disease-associated mutation also showed IFN-γ-dependent accelerated inflammatory responses. Comparisons of peripheral blood- and iPSC-derived macrophages revealed the upregulation of nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) targets in unstimulated macrophages as a common feature. CONCLUSIONS: IFN-γ stimulation is one of the key signals driving aberrant inflammatory responses in BS-associated macrophages. However, long-term treatment with anti-TNF agents ameliorates such abnormalities even in the presence of IFN-γ stimulation. Our data thus suggest that preexposure to TNF or functionally similar cytokines inducing NF-κB-driven proinflammatory signaling during macrophage development is a prerequisite for accelerated inflammatory responses upon IFN-γ stimulation in BS.

Detailed analysis of Japanese patients with adenosine deaminase 2 deficiency reveals characteristic elevation of type II interferon signature and STAT1 hyperactivation.

BACKGROUND: Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive inflammatory disease caused by loss-of-function mutations in both alleles of the ADA2 gene. Most patients with DADA2 exhibit systemic vasculopathy consistent with polyarteritis nodosa, but large phenotypic variability has been reported, and the pathogenesis of DADA2 remains unclear. OBJECTIVES: This study sought to assess the clinical and genetic characteristics of Japanese patients with DADA2 and to gain insight into the pathogenesis of DADA2 by multi-omics analysis. METHODS: Clinical and genetic data were collected from 8 Japanese patients with DADA2 diagnosed between 2016 and 2019. ADA2 variants in this cohort were functionally analyzed by in vitro overexpression analysis. PBMCs from 4 patients with DADA2 were subjected to transcriptome and proteome analyses. Patient samples were collected before and after introduction of anti- TNF-α therapies. Transcriptome data were compared with those of normal controls and patients with other autoinflammatory diseases. RESULTS: Five novel ADA2 variants were identified in these 8 patients and were confirmed pathogenic by in vitro analysis. Anti-TNF-α therapy controlled inflammation in all 8 patients. Transcriptome and proteome analyses showed that upregulation of type II interferon signaling was characteristic of DADA2. Network analysis identified STAT1 as a key regulator and a hub molecule in DADA2 pathogenesis, a finding supported by the hyperactivation of STAT1 in patients' monocytes and B cells after IFN-γ stimulation. CONCLUSIONS: Type II interferon signaling and STAT1 are associated with the pathogenesis of DADA2.

A case of cryopyrin-associated periodic fever syndrome during canakinumab administration complicated by inflammatory bowel disease.

Cryopyrin-associated periodic fever syndrome (CAPS) is a highly debilitating disorder, which is characterized by unregulated interleukin-1ß production driven by autosomal dominantly inherited mutations in the NLRP3 gene. Patients with CAPS often present with early-onset episodes of fever and rash. These patients also present with variable systemic signs and symptoms, such as arthritis, sensorineural hearing loss, chronic aseptic meningitis, and skeletal abnormalities, but minimal gastrointestinal symptoms. Recently, effective therapies for CAPS targeted against interleukin-1 have become available. We report a case of a young Japanese woman with CAPS who developed inflammatory bowel disease during canakinumab therapy. The patient had colostomy after intestinal perforation and changed canakinumab to infliximab. To the best of our knowledge, this is the first report of a case of inflammatory bowel disease secondary to CAPS complicated by gastrointestinal symptoms and arthritis which canakinumab could not control. Patients with CAPS who have symptoms that cannot be controlled by canakinumab should be considered for possible co-morbidities.

Clinical characteristics and treatment of 50 cases of Blau syndrome in Japan confirmed by genetic analysis of the NOD2 mutation.

OBJECTIVES: To collect clinical information and NOD2 mutation data on patients with Blau syndrome and to evaluate their prognosis. METHODS: Fifty patients with NOD2 mutations were analysed. The activity of each NOD2 mutant was evaluated in HEK293 cells by reporter assay. Clinical information was collected from medical records through the attending physicians. RESULTS: The study population comprised 26 males and 24 females aged 0-61 years. Thirty-two cases were sporadic, and 18 were familial from 9 unrelated families. Fifteen different mutations in NOD2 were identified, including 2 novel mutations (p.W490S and D512V); all showed spontaneous nuclear factor kappa B activation, and the most common mutation was p.R334W. Twenty-six patients had fever at relatively early timepoints in the disease course. Forty-three of 47 patients had a skin rash. The onset of disease in 9 patients was recognised after BCG vaccination. Forty-five of 49 patients had joint lesions. Thirty-eight of 50 patients had ocular symptoms, 7 of which resulted in blindness. After the diagnosis of Blau syndrome, 26 patients were treated with biologics; all were antitumour necrosis factor agents. Only 3 patients were treated with biologics alone; the others received a biologic in combination with methotrexate and/or prednisolone. None of the patients who became blind received biologic treatment. CONCLUSIONS: In patients with Blau syndrome, severe joint contractures and blindness may occur if diagnosis and appropriate treatment are delayed. Early treatment with a biologic agent may improve the prognosis.

Intravenous abatacept in Japanese patients with polyarticular-course juvenile idiopathic arthritis: results from a phase III open-label study.

BACKGROUND: To investigate efficacy and safety of intravenous abatacept in Japanese patients with active polyarticular-course juvenile idiopathic arthritis (pJIA). METHODS: In this phase III, open-label, multicenter, single-arm study, patients with pJIA aged 4-17 years who failed ≥1 biologic or methotrexate received weight-tiered (< 75 kg: 10 mg/kg; 75-100 kg: 750 mg; > 100 kg: 1000 mg) intravenous abatacept at Weeks 0, 2, 4, and every 4 weeks thereafter. The study comprised a short-term period (16 weeks) and ongoing long-term period. Primary endpoint: Week 16 JIA-American College of Rheumatology criteria 30 (JIA-ACR30) response rate. Secondary endpoints/outcomes included Week 16 JIA-ACR50/70/90 response and inactive disease rates, Childhood Health Assessment Questionnaire-Disability Index (CHAQ-DI), pharmacokinetics, safety, and immunogenicity. Proportions of patients achieving Juvenile Arthritis Disease Activity Score in 27 joints using C-reactive protein (JADAS27-CRP) remission (score < 1) and minimal disease activity (MDA; score < 3.8), were among exploratory endpoints. RESULTS: All 20 patients who received study medication completed the short-term period. During the long-term period, two patients discontinued due to insufficient efficacy or patient decision. Median age and disease duration at baseline were 10.5 and 0.75 years, respectively. Week 16 JIA-ACR30 response rate (primary endpoint) was 90.0% (18/20). JIA-ACR50/70/90 response and inactive disease rates at Week 16 were 75.0% (15/20), 70.0% (14/20), 35.0% (7/20), and 25.0% (5/20), respectively. At Week 52, JIA-ACR30/50/70/90 response and inactive disease rates were observed by 88.9% (16/18), 88.9% (16/18), 83.3% (15/18), 66.7% (12/18) and 44.4% (8/18), respectively. CHAQ-DI improved after Week 12. JADAS27-CRP remission and MDA were achieved by 15.0% (3/20) and 45.0% (9/20) of patients at Week 16, and by 50.0% (9/18) and 78.0% (14/18) of patients at Week 52, respectively. The mean abatacept pre-dose serum concentration was above the target therapeutic exposure (10 µg/ml) from Week 8 through Week 16. All adverse events were of mild/moderate intensity, except for one case of severe gastroenteritis. No deaths, malignancies, or autoimmune disorders were observed. No antidrug antibodies were detected through Week 16; one patient had a positive immunogenic response during the cumulative period. CONCLUSION: Intravenous abatacept was efficacious and well tolerated in Japanese patients with active pJIA. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01835470 . Date of registration: April 19, 2013.

A low-birth-weight risk assessment scale: development and validation through a questionnaire-based survey.

BACKGROUND: Birth weight is continuously decreasing in Japan since food satiation has become a problem in recent years. The present study aimed to develop and examine the reliability and validity of a scale for the assessment of risk factors for low birth weight in infants born at term. METHODS: A self-administered postal questionnaire survey comprising a low birth weight risk assessment scale was conducted on mothers with children of nursery school or kindergarten age. After item analysis (scale), factor structure was confirmed by an exploratory factor analysis using the main factor method promax rotation. The reliability of this scale was confirmed by Cronbach's α coefficient and Item-Total correlation. The validity was confirmed by known-groups validity and internal validity. RESULTS: The responses of 630 mothers (valid response rate, 18.5%) were analyzed. Factor analysis (principal factor analysis and promax rotation) obtained an optimal scale comprising 25 items in the following nine factors: "guidance at each checkup," "adequate rest," "support from husband," "effects on the fetus," "support from society," "support from family," "effects of minor troubles," "good lifestyle habits," and "fall risk and lifestyle changes." The overall Cronbach's α coefficient for the scale was 0.701. Known-groups validity examination revealed significant differences in scale scores of birth weight, birth history, and maternal smoking status. CONCLUSION: The scale demonstrated internal consistency, construct validity, and known-groups validity, indicating that it can be used as an indicator of low birth weight risk. In the future, this scale may be included in medical questionnaires as part of health guidance for pregnant women at a risk of delivering low birth weight children.

S100A12 and vascular endothelial growth factor can differentiate Blau syndrome and familial Mediterranean fever from systemic juvenile idiopathic arthritis.

OBJECTIVES: Systemic juvenile idiopathic arthritis (sJIA) has recently become regarded as one of the autoinflammatory syndromes (AIS). However, other AIS, such as familial Mediterranean fever (FMF) and Blau syndrome, have been initially misdiagnosed as sJIA because of the clinical similarities. Making the correct diagnosis in the early stage of these AIS is desirable. Therefore, we evaluated serum S100A12 and vascular endothelial growth factor (VEGF) levels to determine if they could be biomarkers for differentiating these AIS. METHOD: Serum S100A12 and VEGF levels were examined in patients with Blau syndrome (n = 4), FMF (n = 4), and sJIA (n = 11) in the active and inactive phases. RESULTS: In the active phase, S100A12 levels were significantly higher in patients with sJIA and FMF compared with those with Blau syndrome (p < 0.001). VEGF levels of patients with sJIA were significantly higher than those of patients with others (p = 0.001). In the inactive phase, there was no significant difference in VEGF levels. However, colchicine-resistant patients or patients without treatment with FMF showed high levels of S100A12 compared with others. CONCLUSIONS: Measuring both serum S100A12 and VEGF levels may be useful for differentiating patients with Blau syndrome and FMF from those with sJIA at the early stage.

Safety and effectiveness of etanercept for treatment of juvenile idiopathic arthritis: Results from a postmarketing surveillance.

OBJECTIVES: The objectives of this surveillance were to determine safety and effectiveness of etanercept in patients with juvenile idiopathic arthritis (JIA). METHODS: In this postmarketing surveillance, patients aged 5-16 years with active polyarthritis JIA were treated with etanercept at the doses approved in the Japanese package insert. The occurrence and seriousness of adverse events (AEs) were assessed using the Japanese Medical Dictionary for Regulatory Activities version 15.1. Effectiveness was determined as the improvement from baseline in disease activity score in 28 joints (DAS28)-erythrocyte sedimentation rate (ESR), remission, and physician's assessment of overall improvement. The number of responders was expressed as a percentage. The last observation carried forward method was used to impute missing data. RESULTS: Safety analysis included 102 patients; 22 patients experienced 36 treatment-related AEs, three of which were unexpected. None of the AEs were deemed to need special safety warnings. Effectiveness analysis included 87 patients. At 24 weeks, 29/46 (63.0%) patients demonstrated either good or moderate response in DAS28-4/ESR and treatment was assessed to be markedly effective or effective by physicians in 79/83 (95.2%) patients. CONCLUSIONS: These data are consistent with earlier reports showing that etanercept was effective and demonstrated no safety signals in patients with JIA.

Characteristics and outcome of intractable vasculitis syndrome in children: Nation-wide survey in Japan.

OBJECTIVE: Primary systemic vasculitis (PSV) is a rare disorder in children and difficult to distinguish from other diseases. However, appropriate diagnosis and prompt treatment will affect on the morbidity and mortality of intractable PSV. In this study, we conducted a nationwide survey in Japan, to clarify epidemiology and clinical outcome of PSV. METHODS: We had sent survey questionnaires to most of the Japanese institutions that employed pediatricians, requesting the number of patients with refractory PSV who were diagnosed and treated between 2007 and 2011. Respondents were asked to provide detailed information on the clinical and laboratory features of each case they had managed. Those with Kawasaki disease or Henoch-Shönlein purpura vasculitis (IgA vasculitis) were excluded. RESULTS: Of all the institutions surveyed, 1123 (37.3%) patients responded, finally, total of 49 patients with intractable PSV, defined by those with resistant to treatment and steroid-dependent, or with any complication associated with prognosis, were selected. The diagnosis was Takayasu arteritis in 31, polyarteritis nodosa in 11, granulomatosis with polyangitis in 2, microscopic polyangitis in 1, and ANCA negative microscopic polyangitis in 1. In those with Takayasu arteritis, 67% were treated with an immunosuppressive agent, 22% with biological modifiers, and 16% with surgical procedures. In other types of disease, 88% of the patients were treated with an immunosuppressive agent, and 12% with biological modifiers. Two with Takayasu arteritis died being terminally ill. CONCLUSION: This nationwide survey establishes the heterogeneous characteristics of PSV in children. Although questionnaire-based, the results of our analysis should be useful in planning prospective studies to identify the most effective therapy for each subtype of multifaceted disease.

Treatable renal disease in children with silent lupus nephritis detected by baseline biopsy: association with serum C3 levels.

Lupus nephritis is identified in up to 75% of patients with juvenile systemic lupus erythematosus and may present with abnormal urinary findings (overt lupus nephritis) or be apparent only upon renal biopsy (silent lupus nephritis). We investigated whether serum complement levels correlate with renal pathology in pediatric patients with silent lupus nephritis. We performed baseline renal biopsy in 45 children diagnosed with juvenile systemic lupus erythematosus who were admitted to Kagoshima University Hospital between January 2000 and June 2015. Patients were classified as having overt or silent lupus nephritis based on urinary findings at renal biopsy. Silent lupus nephritis was identified in 55.5% (25/45) of cases. Of these, 6 (13.3%) were classified as class III nephritis, according to the International Society of Nephrology/Renal Pathology Society criteria. Decreased serum C3 levels were associated with the renal pathology classification for patients with silent but not with overt lupus nephritis. No differences in serum C4 levels were identified between cases of silent and overt lupus nephritis. Baseline renal biopsy is a critical component of the work-up of juvenile systemic lupus erythematosus as treatable renal pathology may be present in the absence of urinary signs. Serum C3 may be an important marker of the progression of silent lupus nephritis.

A 2-year-old Japanese girl with TNF receptor-associated periodic syndrome: A case report of the youngest diagnosed proband in Japan.

We report a 2-year-old girl with tumor necrosis factor receptor-associated periodic syndrome (TRAPS) who is the youngest proband diagnosed in Japan. Recurrent fever had started at her 6 months of age, and she had the familial history of recurrent fever, suggesting underlying genetic disorder, in her father and grandfather. Careful clinical observation of characteristics of fever with disease course and the familial history of recurrent fever may lead to diagnosis of TRAPS in early infancy.

Prediction of long-term remission of oligo/polyarticular juvenile idiopathic arthritis with S100A12 and vascular endothelial growth factor.

OBJECTIVES: This study aimed to evaluate the usefulness of S100A12 and vascular endothelial growth factor (VEGF) for predicting the stability of remission for discontinuing methotrexate (MTX) and/or biological agents in Japanese patients with oligo/polyarticular juvenile idiopathic arthritis (JIA). METHODS: Forty-four patients with oligo/polyarticular JIA who received MTX with or without biological agents were enrolled. Serum concentration of both S100A12 and VEGF were simultaneously evaluated by ELISA in active and in remission phase determined by activity markers including DAS-28. RESULTS: S100A12 and VEGF were correlated with DAS-28. Of the 22 patients with oligo/polyarticular JIA in clinical remission, 13 patients with low S100A12 and VEGF concentrations could discontinue treatment without relapse over 2 years. However, nine patients without low S100A12 and VEGF concentrations relapsed afterwards, even though they had been in clinical remission. The cut-off levels of S100A12 and VEGF for division into two groups of the maintenance remission and relapse groups were 177 ng/ml and 158 pg/ml, respectively. CONCLUSIONS: S100A12 and VEGF are useful markers for assessing disease activity of oligo/polyarticular JIA in remission phase. These markers should be kept low when clinicians consider tapering or discontinuing treatments in oligo/polyarticular JIA patients.

Interleukin-18 for predicting the development of macrophage activation syndrome in systemic juvenile idiopathic arthritis.

To assess the role of IL-6/IL-18 in the pathogenesis of systemic juvenile idiopathic arthritis (s-JIA) and to investigate the clinical significance of serum IL-18 levels for predicting macrophage activation syndrome (MAS) development, we measured the serum IL-6/IL-18 levels in 76s-JIA patients, including 15 with MAS, and compared them with the clinical features. We identified 2 distinct subsets on the basis of serum IL-6/IL-18 levels. The IL-18-dominant subset had more patients who developed MAS. Serum IL-18 levels during active phase in patients with MAS were significantly higher than those without MAS. The cutoff value of serum IL-18 levels for predicting MAS development was 47750 pg/ml. The patients with IL-18 dominant subset at their disease onset were significantly more likely to develop MAS after TCZ therapy started. IL-18 might have a key role in the pathogenesis of MAS. Serum IL-18 levels >47750 pg/ml might be useful to predict MAS development.

Somatic NLRP3 mosaicism in Muckle-Wells syndrome. A genetic mechanism shared by different phenotypes of cryopyrin-associated periodic syndromes.

UNLABELLED: : Familial cold autoinflammatory syndrome, Muckle-Wells syndrome (MWS), and chronic, infantile, neurological, cutaneous and articular (CINCA) syndrome are dominantly inherited autoinflammatory diseases associated to gain-of-function NLRP3 mutations and included in the cryopyrin-associated periodic syndromes (CAPS). A variable degree of somatic NLRP3 mosaicism has been detected in ≈35% of patients with CINCA. However, no data are currently available regarding the relevance of this mechanism in other CAPS phenotypes. OBJECTIVE: To evaluate somatic NLRP3 mosaicism as the disease-causing mechanism in patients with clinical CAPS phenotypes other than CINCA and NLRP3 mutation-negative. METHODS: NLRP3 analyses were performed by Sanger sequencing and by massively parallel sequencing. Apoptosis-associated Speck-like protein containing a CARD (ASC)-dependent nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB) activation and transfection-induced THP-1 cell death assays determined the functional consequences of the detected variants. RESULTS: A variable degree (5.5-34.9%) of somatic NLRP3 mosaicism was detected in 12.5% of enrolled patients, all of them with a MWS phenotype. Six different missense variants, three novel (p.D303A, p.K355T and p.L411F), were identified. Bioinformatics and functional analyses confirmed that they were disease-causing, gain-of-function NLRP3 mutations. All patients treated with anti-interleukin1 drugs showed long-lasting positive responses. CONCLUSIONS: We herein show somatic NLRP3 mosaicism underlying MWS, probably representing a shared genetic mechanism in CAPS not restricted to CINCA syndrome. The data here described allowed definitive diagnoses of these patients, which had serious implications for gaining access to anti-interleukin 1 treatments under legal indication and for genetic counselling. The detection of somatic mosaicism is difficult when using conventional methods. Potential candidates should benefit from the use of modern genetic tools.

Performance of current guidelines for diagnosis of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis.

OBJECTIVE: To compare the capacity of the 2004 diagnostic guidelines for hemophagocytic lymphohistiocytosis (HLH-2004) with the capacity of the preliminary diagnostic guidelines for systemic juvenile idiopathic arthritis (JIA)-associated macrophage activation syndrome (MAS) to discriminate MAS complicating systemic JIA from 2 potentially confusable conditions, represented by active systemic JIA without MAS and systemic infection. METHODS: International pediatric rheumatologists and hemato-oncologists were asked to retrospectively collect clinical information from patients with systemic JIA-associated MAS and confusable conditions. The ability of the guidelines to differentiate MAS from the control diseases was evaluated by calculating the sensitivity and specificity of each set of guidelines and the kappa statistics for concordance with the physician's diagnosis. Owing to the fact that not all patients were assessed for hemophagocytosis on bone marrow aspirates and given the lack of data on natural killer cell activity and soluble CD25 levels, the HLH-2004 guidelines were adapted to enable the diagnosis of MAS when 3 of 5 of the remaining items (3/5-adapted) or 4 of 5 of the remaining items (4/5-adapted) were present. RESULTS: The study sample included 362 patients with systemic JIA and MAS, 404 patients with active systemic JIA without MAS, and 345 patients with systemic infection. The best capacity to differentiate MAS from systemic JIA without MAS was found when the preliminary MAS guidelines were applied. The 3/5-adapted HLH-2004 guidelines performed better than the 4/5-adapted guidelines in distinguishing MAS from active systemic JIA without MAS. The 3/5-adapted HLH-2004 guidelines and the preliminary MAS guidelines with the addition of ferritin levels ≥500 ng/ml discriminated best between MAS and systemic infections. CONCLUSION: The preliminary MAS guidelines showed the strongest ability to identify MAS in systemic JIA. The addition of hyperferritinemia enhanced their capacity to differentiate MAS from systemic infections. The HLH-2004 guidelines are likely not appropriate for identification of MAS in children with systemic JIA.