C-reactive protein is more suitable than Serum Amyloid A to monitor crises and attack-free periods in Systemic Auto-Inflammatory Diseases.

BACKGROUND: With their broad presentations and no global biomarker to discriminate crises and attack-free periods, Systemic Auto-Inflammatory Diseases (SAID) are difficult to manage. This study assessed Serum Amyloid A (SAA), C-reactive protein (CRP) and serum calprotectin as potential biomarkers to monitor patients with SAID. METHOD: SAA (already studied in Familial Mediterranean Fever (FMF)), CRP and serum calprotectin were measured on SAID adult patients from Juvenile Inflammatory Rheumatism (JIR) cohort during their follow-up visits between 2020 and 2022. Crises and attack-free periods were clinically determined. RESULTS: 96 measures, mainly from FMF (43 %) and Unclassified SAID (USAID) (37 %) patients were included. Using ROC curves, a threshold with sensitivity and specificity of/over 75 % was determined for SAA (9 mg/L) and CRP (9 mg/L) but not for serum calprotectin, not investigated further. With this threshold, the results were similar in FMF and USAID patients' subgroups. SAA and CRP showed a positive correlation with crises and attack-free periods in SAID patients (r = 0.4796, p < 0.001 and r = 0.5525, p < 0.001, respectively) as in FMF and USAID patients, with no significant difference between both markers in diagnosis value and ROC curves Area Under Curve (AUC) (p = 0.32). Only the CRP results were not influenced by obesity. CONCLUSION: SAA and CRP can discriminate crisis and attack-free periods in our cohort of SAID patients mainly composed of FMF and USAID patients. However, only CRP can be used regardless of body mass index. It is the first report of common biomarkers for all SAID, including USAID patients, with CRP widely accessible in routine worldwide.

Functional diversity of NLRP3 gain-of-function mutants associated with CAPS autoinflammation.

NLRP3-associated autoinflammatory disease is a heterogenous group of monogenic conditions caused by NLRP3 gain-of-function mutations. The poor functional characterization of most NLRP3 variants hinders diagnosis despite efficient anti-IL-1 treatments. Additionally, while NLRP3 is controlled by priming and activation signals, gain-of-functions have only been investigated in response to priming. Here, we characterize 34 NLRP3 variants in vitro, evaluating their activity upon induction, priming, and/or activation signals, and their sensitivity to four inhibitors. We highlight the functional diversity of the gain-of-function mutants and describe four groups based on the signals governing their activation, correlating partly with the symptom severity. We identify a new group of NLRP3 mutants responding to the activation signal without priming, associated with frequent misdiagnoses. Our results identify key NLRP3 residues controlling inflammasome activity and sensitivity to inhibitors, and antagonistic mechanisms with broader efficacy for therapeutic strategies. They provide new insights into NLRP3 activation, an explanatory mechanism for NLRP3-AID heterogeneity, and original tools for NLRP3-AID diagnosis and drug development.

Gut microbiota alterations are associated with phenotype and genotype in familial Mediterranean fever.

OBJECTIVE: FMF is the most common monogenic autoinflammatory disease associated with MEFV mutations. Disease phenotype and response to treatment vary from one patient to another, despite similar genotype, suggesting the role of environmental factors. The objective of this study was to analyse the gut microbiota of a large cohort of FMF patients in relation to disease characteristics. METHODS: The gut microbiotas of 119 FMF patients and 61 healthy controls were analysed using 16 s rRNA gene sequencing. Associations between bacterial taxa, clinical characteristics, and genotypes were evaluated using multivariable association with linear models (MaAslin2), adjusting on age, sex, genotype, presence of AA amyloidosis (n = 17), hepatopathy (n = 5), colchicine intake, colchicine resistance (n = 27), use of biotherapy (n = 10), CRP levels, and number of daily faeces. Bacterial network structures were also analysed. RESULTS: The gut microbiotas of FMF patients differ from those of controls in having increased pro-inflammatory bacteria, such as the Enterobacter, Klebsiella and Ruminococcus gnavus group. Disease characteristics and resistance to colchicine correlated with homozygous mutations and were associated with specific microbiota alteration. Colchicine treatment was associated with the expansion of anti-inflammatory taxa such as Faecalibacterium and Roseburia, while FMF severity was associated with expansion of the Ruminococcus gnavus group and Paracoccus. Colchicine-resistant patients exhibited an alteration of the bacterial network structure, with decreased intertaxa connectivity. CONCLUSION: The gut microbiota of FMF patients correlates with disease characteristics and severity, with an increase in pro-inflammatory taxa in the most severe patients. This suggests a specific role for the gut microbiota in shaping FMF outcomes and response to treatment.

Pathogenic variants in the NLRP3 LRR domain at position 861 are responsible for a boost-dependent atypical CAPS phenotype.

BACKGROUND: Cryopyrin-associated periodic syndrome (CAPS) is associated with NLRP3 pathogenic variants, mostly located in the NACHT (neuronal apoptosis inhibitor protein, MHC class 2 transcription activator, incompatibility locus protein from Podospora anserina, telomerase-associated protein) domain. Cold-induced urticarial rash is among the main clinical features. However, this study identified a series of 14 patients with pathogenic variants of the Y861 residue (p.Tyr861) of the LRR domain of NLRP3 and minimal prevalence of cold-induced urticarial rash. OBJECTIVES: This study aimed to address a possible genotype/phenotype correlation for patients with CAPS and to investigate at the cellular levels the impact of the Y861C substitution (p.Tyr861Cys) on NLRP3 activation. METHODS: Clinical features of 14 patients with CAPS and heterozygous substitution at position 861 in the LRR domain of NLRP3 were compared to clinical features of 48 patients with CAPS and pathogenic variants outside the LRR domain of NLRP3. IL-1ß secretion by PBMCs and purified monocytes from patients and healthy donors was evaluated following LPS and monosodium urate crystal stimulation. RESULTS: Patients with substitution at position 861 of NLRP3 demonstrated a higher prevalence of sensorineural hearing loss while being less prone to skin urticarial. In contrast to patients with classical CAPS, cells from patients with a pathogenic variant at position 861 required an activation signal to secrete IL-1ß but produced more IL-1ß during the early and late phase of secretion than cells from healthy donors. CONCLUSIONS: Pathogenic variants of Y861 of NLRP3 drive a boost-dependent oversecretion of IL-1ß associated with an atypical CAPS phenotype.

Diagnostic and therapeutic algorithms for monogenic autoinflammatory diseases presenting with recurrent fevers among adults.

Autoinflammatory diseases (AIDs) are defined as disorders of innate immunity. They were initially defined in contrast to autoimmune diseases because of the lack of involvement of the adaptive immune system and circulating autoantibodies. The four monogenic AIDs first described are called the 'historical' AIDs and include FMF (associated with MEFV mutations), cryopyrinopathies (associated with NLRP3 mutations), TNF receptor-associated periodic syndrome (associated with TNFRSF1A mutations) and mevalonate kinase deficiency (MKD; associated with MVK mutations). In the last 10 years, >50 new monogenic AIDs have been discovered due to genetic advances. The most important discovery for adult patients is VEXAS syndrome associated with somatic UBA1 mutations leading to an AID affecting mostly elderly men. Diagnosis of monogenic AIDs is based on personal and family history and detailed analysis of symptoms associated with febrile attacks in the context of elevated peripheral inflammatory markers. This review proposes a practical approach for the diagnosis of the main monogenic AIDs among adult patients.

JAK inhibitors in difficult-to-treat adult-onset Still's disease and systemic-onset juvenile idiopathic arthritis.

OBJECTIVES: Excessive and inappropriate production of pro-inflammatory cytokines plays a key role in Still's disease. Janus kinase inhibitor (JAKi) agents mainly block pro-inflammatory cytokine pathways, notably IL-6 and IFN. The objective was to assess the efficacy and safety of JAKi agents in difficult-to-treat systemic JIA or adult-onset Still's disease (AOSD). METHODS: This retrospective study was based on a national survey conducted in the departments of rheumatology, paediatric rheumatology and internal medicine of French hospitals regarding systemic JIA and AOSD patients who received JAKi agents. The data were collected with a standardized questionnaire and analysed at different times (treatment initiation, months 1, 3 and 6 and the end of follow-up). RESULTS: Nine patients (seven adults) were included. All patients showed inadequate response to CS or conventional synthetic or biologic DMARDs. Baricitinib was used in five patients, ruxolitinib in two, tofacitinib in two and upadacitinib in one. A JAKi was used combined with CS in all but two patients. A JAKi was associated with anakinra and CS in one patient, and with MTX, anakinra and CS in another. The median (range) follow-up was 16 (1-33) months. Two cases out of nine showed complete remission, 3/9 partial response and 4/9 treatment failure. At the last visit, CS could be decreased but not stopped. Tolerance of the JAKi was acceptable (no severe adverse events). CONCLUSION: JAKi agents may be a therapeutic option for some patients with difficult-to-treat Still's disease, especially those with partial response to medium- or high-dose CS or biologics.

Vasculitis and familial Mediterranean fever: Description of 22 French adults from the juvenile inflammatory rheumatism cohort.

Objective: The frequency of vasculitis may be increased in patients with Familial Mediterranean Fever (FMF), according to several studies. Our aim was to assess the characteristics of French adult patients with both diseases. Methods: Patients with vasculitis were selected from patients followed for FMF in the French JIR-cohort. Results: Twenty-two patients were included [polyarteritis nodosa (PAN) n = 10, IgA vasculitis n = 8, unclassified vasculitis n = 2, granulomatosis with polyangiitis n = 1, and microscopic polyangiitis n = 1]. Pathogenic mutations in exon 10 were found in all 21 patients (96%) for which MEFV testing results were available, and 18 (82%) had two pathogenic mutations. Histology showed vasculitis in 59% of patients. Most patients with FMF-associated PAN were HBV-negative and had an inactive FMF before PAN onset, and 40% had a peri-renal or central nervous system bleeding. Most patients with FMF-associated IgA vasculitis had an active FMF before vasculitis onset, and 25% had digestive bleeding. Both patients with unclassified vasculitis had ischemic and/or hemorrhagic complications. Conclusion: This study confirms the predominance of PAN and IgA vasculitis in patients with FMF and the high frequency of bleeding in FMF-associated PAN. FMF should be considered in case of persistent symptoms and/or inflammatory syndrome despite vasculitis treatment in Mediterranean patients.

Role of non-invasive methods in detecting liver impairment in familial Mediterranean fever adult patients with persistent hepatic cytolysis.

Familial Mediterranean fever (FMF) patients may have hepatic cytolysis, although its origin is not formally elucidated. We aimed to evaluate liver involvement in familial Mediterranean fever (FMF) using non-invasive methods. All adult FMF patients harboring two non-ambiguous mutations of the MEFV gene with hepatic cytolysis were identified in a French tertiary adult center for FMF. Liver impairment was explored with FibroMax (a non-invasive method to estimate hepatic steatosis, necrosis, inflammation and fibrosis) and liver ultrasound. Among 520 FMF adult patients, 43 had persistent hepatic cytolysis and 20 patients were included (11 women, median age at inclusion: 49.5 years). According to the FibroMax results, patients were classified as having steatosis, fibrosis, and possible or definite nonalcoholic steato-hepatitis in 10 (50%), 9 (45%) and 7 (35%) of cases, respectively. The score of steatosis did not seem associated with the usual metabolic risk factors. No significant association was found between the cumulated dose of colchicine and any of the scores included in FibroMax. In adult FMF patients with persistent hepatic cytolysis, steatosis is the first cause to consider even in the absence of usual metabolic risk factors, suggesting other mechanisms. Colchicine did not seem to be involved in this toxicity.

COVID-19 infection among patients with autoinflammatory diseases: a study on 117 French patients compared with 1545 from the French RMD COVID-19 cohort: COVIMAI - the French cohort study of SARS-CoV-2 infection in patient with systemic autoinflammatory diseases.

OBJECTIVE: There is little known about SARS-CoV-2 infection in patients with systemic autoinflammatory disease (SAID). This study aimed to describe epidemiological features associated with severe disease form and death. Mortality between patients with and without SAID hospitalised for SARS-CoV-2 infection was compared. METHODS: A national multicentric prospective cohort study was conducted from the French Rheumatic and Musculoskeletal Diseases (RMD) COVID-19 cohort. Patients with SAID were matched with patients with non-SAID on age±7 years, gender and number of comorbidities to consider important confounding factors. Impact of SAID on severity of SARS-CoV-2 infection was analysed using multinomial logistic regression for severity in three classes (mild, moderate and severe with mild status as reference). Fine-Gray regression model for length of hospital stay and binomial logistic regression model for risk of death at 30 days. RESULTS: We identified 117 patients with SAID (sex ratio 0.84, 17 children) and compared them with 1545 patients with non-autoinflammatory immune-mediated inflammatory disorders (non-SAID). 67 patients had a monogenic SAID (64 with familial Mediterranean fever). Other SAIDs were Behçet' disease (n=21), undifferentiated SAID (n=16), adult-onset Still disease (n=9) and systemic-onset juvenile idiopathic arthritis (n=5). Ten adults developed severe form (8.6%). Six patients died. All children had a benign disease. After matching on age±7 years, sex and number of comorbidities, no significant difference between the two groups in length of stay and the severity of infection was noted. CONCLUSION: As identified in the whole French RMD COVID-19 cohort, patients with SAID on corticosteroids and with multiple comorbidities are prone to develop more severe COVID-19 forms.

AA amyloidosis complicating monoclonal gammopathies, an unusual feature validating the concept of "monoclonal gammopathy of inflammatory significance"?

INTRODUCTION: AL amyloidosis is caused by the proliferation of an immunoglobulin-secreting B cell clone. AA amyloidosis is a rare complication of chronic inflammation. However, some patients present with diseases combining monoclonal immunoglobulin production and chronic inflammation. The aim of this work was to describe cases of AA amyloidosis associated with monoclonal gammopathies. PATIENTS AND METHODS: We reviewed all patients reported in French national amyloid centres presenting with AA amyloidosis and monoclonal gammopathy and performed a literature review. The quality of AA amyloidosis diagnosis and the causal relationship with monoclonal gammopathy were assessed. RESULTS: In total, four patients from our centres and eight from the literature fulfilled the inclusion criteria. The haematological disorders presenting with monoclonal gammopathy were as follows: Waldenström macroglobulinaemia (n = 8), Schnitzler syndrome (n = 2), multiple myeloma (n = 1) and monoclonal gammopathy of undetermined significance (n = 1). Treatment strategies varied among the cases, with the treatment of the haematological disorder in 4 and anti-inflammatory treatment in 2. CONCLUSION: Monoclonal gammopathies might be a rare and poorly known cause of AA amyloidosis. Such monoclonal gammopathies could be named "monoclonal gammopathies of inflammatory significance."

Amyloid Goiter in Familial Mediterranean Fever: Description of 42 Cases from a French Cohort and from Literature Review.

Our aim was to describe the main features of amyloid goiter in adults with amyloidosis secondary to familial Mediterranean fever. Therefore, we analyzed cases from a French cohort of familial Mediterranean fever patients with amyloidosis and from literature review. Forty-two cases were identified: 9 from the French cohort and 33 from literature review. Ninety percent of patients were on hemodialysis for renal amyloidosis before the development of goiter. The goiter grew up rapidly in 88% of cases; 75.6% of patients were euthyroid, 58% displayed dyspnea, and 44.8% dysphagia. Various features were seen on ultrasound, from diffuse to multinodular goiter. When it was performed, fine-needle aspiration biopsy almost always revealed amyloidosis. Thirty-one patients underwent thyroidectomy: to manage compressive symptoms (72%) or rule out malignancy (27%). Histology showed mature adipose tissue in 64% of cases and lymphocytic infiltration in 21.4%. In conclusion, amyloid goiter in familial Mediterranean fever preferentially occurs in patients with end stage renal failure. Fine-needle aspiration biopsy seems to be a sensitive exam for diagnosis, but thyroidectomy remains sometimes necessary to rule out malignancy or release compressive symptoms.

[Familial Mediterranean fever in 2020]. / Fièvre méditerranéenne familiale en 2020.

Familial Mediterranean fever is the most frequent autoinflammatory disease with autosomal recessive transmission. Most patients carry mutations in the MEFV gene encoding the protein marenostrin/pyrin. It is characterised by short ant recurrent attacks of fever and serositis with abdominal or thoracic pain, usually lasting less than 3 days, raised inflammatory biologic markers in an individual of Mediterranean origin. Colchicine has been shown to be effective in prevention of inflammatory attacks and development of amyloidosis which is responsible of nephrotic syndrome and chronic renal failure. Better knowledge in pathogenic mechanisms permitted identification of interleukin-1 beta (Il-1 ß) as the main cytokine target. Anti-IL-1 therapy must be considered as a second line treatment in case of persistent inflammation or colchicine intolerance.

Tumour necrosis factor receptor-1 associated periodic syndrome (TRAPS)-related AA amyloidosis: a national case series and systematic review.

OBJECTIVES: TNF receptor-1-associated periodic syndrome (TRAPS) is a rare autosomal dominant autoinflammatory disorder associated with mutations in the TNF receptor super family 1 A (TNFRSF1A) gene. AA amyloidosis (AA) is the most severe complication of TRAPS. To study the occurrence and prognosis of AA in TRAPS, we conducted a retrospective study of all French cases and a systematic literature review. METHODS: This case series includes TRAPS patients followed by our centre from 2000 to 2020 presenting with histologically confirmed AA. We conducted a systematic literature review on the PubMed and EMBASE databases for articles published up to February 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and using the keywords: amyloidoisis, amyloid, TNF receptor-associated periodic syndrome, TNF receptor-associated periodic syndrome, tumor necrosis factor receptor-associated periodic syndrome, TRAPS, TNFRSF1A, familial hibernian fever and hibernian familial fever. RESULTS: A total of 41 TRAPS with AA were studied: three new patients and 38 cases from the literature. AA diagnosis preceded that of TRAPS in 96% of cases, and 17/36 (47%) required renal replacement therapy. Death occurred in 5/36 (14%) with a median follow-up of 23 months. Effect of biologics on AA were available for 21 regimens in 19 patients: 10 improved renal function, seven stabilized and four worsened. Four patients (36% of transplanted patients) relapse AA on kidney graft (only one under etanercept). CONCLUSION: TRAPS is revealed by AA in most cases. Therefore, clinical features of TRAPS should be screened for in AA patients. IL-1 antagonist can help to normalize inflammation and to preserve renal function.