Background Current data suggest that COVID-19 is less frequent in children, with a milder course. However, over the past weeks, an increase in the number of children presenting to hospitals in the greater Paris region with a phenotype resembling Kawasaki disease (KD) has led to an alert by the French national health authorities. Methods Multicentre compilation of patients with KD in Paris region since April 2020, associated with the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (‘Kawa-COVID-19’). A historical cohort of ‘classical’ KD served as a comparator. Results Sixteen patients were included (sex ratio=1, median age 10 years IQR (4·7 to 12.5)). SARS-CoV-2 was detected in 12 cases (69%), while a further three cases had documented recent contact with a quantitative PCR-positive individual (19%). Cardiac involvement included myocarditis in 44% (n=7). Factors prognostic for the development of severe disease (ie, requiring intensive care, n=7) were age over 5 years and ferritinaemia >1400 µg/L. Only five patients (31%) were successfully treated with a single intravenous immunoglobulin (IVIg) infusion, while 10 patients (62%) required a second line of treatment. The Kawa-COVID-19 cohort differed from a comparator group of ‘classical’ KD by older age at onset 10 vs 2 years (p<0.0001), lower platelet count (188 vs 383 G/L (p<0.0001)), a higher rate of myocarditis 7/16 vs 3/220 (p=0.0001) and resistance to first IVIg treatment 10/16 vs 45/220 (p=0.004). Conclusion Kawa-COVID-19 likely represents a new systemic inflammatory syndrome temporally associated with SARS-CoV-2 infection in children. Further prospective international studies are necessary to confirm these findings and better understand the pathophysiology of Kawa-COVID-19. Trial registration number NCT02377245

BD is a systemic inflammatory disease with a variable vasculitis. Paediatric onset is very rare and carries a strong genetic component. Oral ulcers and fever of unknown origin are frequent at onset and difficult to distinguish from other inflammatory disorders; therefore, expert opinion is still mandatory to recognize the disease early. An international expert consensus has recently proposed new classification criteria for children with BD. The clinical spectrum of BD is heterogeneous and influenced by gender, ethnicity and country of residence. Young males have the worst prognosis with significantly more frequent neurological, ocular and vascular involvement. BD treatment is aimed at alleviating inflammation. Among all drugs, TNFα inhibitors have become a standard to control severe ocular, neurological and digestive system involvement.

Despite their limited licensed indications, anti–interleukin-1 (anti–IL-1) agents are often used in clinical practice for an increasing number of auto-inflammatory diseases. We conducted a national cross-sectional observational study from January 2011 to January 2013 to record the off-label use of such agents in France. We aimed to estimate the off-label use of anti–IL-1 treatments in France, assess their efficacy in rare diseases, and increase the reporting of their possible side effects. Physicians answered a questionnaire that covered patient and disease data, anti–IL-1 agent use, efficacy and adverse events. The study involved adult or paediatric patient who had received an anti–IL-1 agent after January 2005 in France. In total, 189 patients from 38 centres were included. The main diseases were adult-onset Still’s disease (AOSD) (35), gout (28), systemic juvenile idiopathic arthritis (27), cryopyrin-associated periodic syndrome (CAPS) (21), familial Mediterranean fever (14) and mevalonate kinase deficiency (12). The main off-label used agent was anakinra, used at least once for 185 patients, with canakinumab used for 25. Anakinra was effective in most patients (90%), with higher complete clinical response rates for Schnitzler’s syndrome, gout, CAPS and AOSD. Overall, 58% of patients showed at least one adverse event, mainly minor injection-site reactions. The main reported serious adverse event was severe infection. Injection-site reactions and liver toxicity were significantly more frequent in children than adults. The main non-cutaneous adverse event was liver toxicity, significantly associated with treatment duration. Weight gain was reported in about 10% of patients and was associated with treatment duration and CAPS. Canakinumab was rarely used and showed better cutaneous tolerance than anakinra but similar rates of non-cutaneous and severe adverse events. Anakinra was well tolerated and effective in most patients with various inflammatory diseases. The main adverse events were mild injection-site reactions, especially in children. The survey allowed for collecting limited information on the off-label use of canakinumab.

Introduction: To assess the effect of canakinumab, a fully human anti-interleukin-1β antibody, on symptoms and health-related quality of life (HRQoL) in patients with cryopyrin-associated periodic syndrome (CAPS). Methods: In this 48-week, phase 3 study, patients with CAPS received canakinumab 150 mg subcutaneously at 8-week intervals. All patients (n = 35) received canakinumab during weeks 1 through 8; weeks 9 through 24 constituted a double-blind placebo-controlled withdrawal phase, and weeks 24 through 48 constituted an open-label phase in which all patients received canakinumab. Patient and physician assessments of symptoms, levels of inflammatory markers, and HRQoL were performed. Results: Rapid symptom remission was achieved, with 89% of patients having no or minimal disease activity on day 8. Responses were sustained in patients receiving 8-weekly canakinumab. Responses were lost during the placebo-controlled phase in the placebo group and were regained on resuming canakinumab therapy in the open-label phase. Clinical responses were accompanied by decreases in serum levels of C-reactive protein, serum amyloid A protein, and interleukin-6. HRQoL scores at baseline were considerably below those of the general population. Improvements in all 36-item Short-Form Health Survey (SF-36) domain scores were evident by day 8. Scores approached or exceeded those of the general U.S. population by week 8 and remained stable during canakinumab therapy. Improvements in bodily pain and role-physical were particularly marked, increasing by more than 25 points from baseline to week 8. Therapy was generally well tolerated. Conclusions: Canakinumab, 150 mg, 8-weekly, induced rapid and sustained remission of symptoms in patients with CAPS, accompanied by substantial improvements in HRQoL. Trial registration: Clintrials.gov NCT00465985

To identify the clinical characteristics, reasons for use and response to treatment with anakinra in a series of patients with Kawasaki Disease (KD). A retrospective chart review of patients treated with anakinra for KD diagnosed according to the AHA criteria. We compared clinical, biological and echocardiographic characteristics of KD before and after anakinra use. We analysed reasons for use of anakinra, and compared treatment regimens used in 7 European KD referral centres. Eight boys and 3 girls with treatment-refractory KD, aged 4 months to 9 years old, received at least 2 different KD treatments prior to anakinra, which was given on mean at 25 days after disease onset (8 to 87 days). The main reasons for use of anakinra were clinical and biological inflammation, progression of coronary dilatations, and severe myocarditis with cardiac failure. Doses of anakinra ranged from 2 to 8 mg/kg and duration varied from 6 to 81 days. Efficacy of anakinra was judged in terms of fever resolution (100%), decrease of CRP (100%), and in terms of its effect on coronary artery dilatation Z scores, which decreased in 10/11 patients and increased in one who died suddenly of pericardial hemorrhage. Anakinra used late in the disease course led to a rapid and sustained improvement in clinical and biological inflammation. Our retrospective analysis did show neither a striking nor a rapid decrease of coronary dilatations and we cannot determine if anakinra itself had an effect on coronary artery dimensions.