BackgroundThe transepithelial transport of electrolytes, solutes, and water in the kidney is a well-orchestrated process involving numerous membrane transport systems. Basolateral potassium channels in tubular cells not only mediate potassium recycling for proper Na+,K+-ATPase function but are also involved in potassium and pH sensing. Genetic defects in KCNJ10 cause EAST/SeSAME syndrome, characterized by renal salt wasting with hypokalemic alkalosis associated with epilepsy, ataxia, and sensorineural deafness.MethodsA candidate gene approach and whole-exome sequencing determined the underlying genetic defect in eight patients with a novel disease phenotype comprising a hypokalemic tubulopathy with renal salt wasting, disturbed acid-base homeostasis, and sensorineural deafness. Electrophysiologic studies and surface expression experiments investigated the functional consequences of newly identified gene variants.ResultsWe identified mutations in the KCNJ16 gene encoding KCNJ16, which along with KCNJ15 and KCNJ10, constitutes the major basolateral potassium channel of the proximal and distal tubules, respectively. Coexpression of mutant KCNJ16 together with KCNJ15 or KCNJ10 in Xenopus oocytes significantly reduced currents.ConclusionsBiallelic variants in KCNJ16 were identified in patients with a novel disease phenotype comprising a variable proximal and distal tubulopathy associated with deafness. Variants affect the function of heteromeric potassium channels, disturbing proximal tubular bicarbonate handling as well as distal tubular salt reabsorption.

About 10-20% of patients with Kawasaki disease (KD) are unresponsive to intravenous immunoglobulin (IVIg) and are at increased risk of coronary artery abnormalities (CAAs). Early identification is critical to initiate aggressive therapies, but available scoring systems lack sensitivity in non-Japanese populations. We investigated the accuracy of 3 Japanese scoring systems and studied factors associated with IVIg unresponsiveness in a large multiethnic French population of children with KD to build a new scoring system. Children admitted for KD between 2011-2014 in 65 centers were enrolled. Factors associated with second line-treatment; i.e. unresponsiveness to initial IVIg treatment, were analyzed by multivariate regression analysis. The performance of our score and the Kobayashi, Egami and Sano scores were compared in our population and in ethnic subgroups. Overall, 465 children were reported by 84 physicians; 425 were classified with KD (55% European Caucasian, 12% North African/ Middle Eastern, 10% African/Afro-Caribbean, 3% Asian and 11% mixed). Eighty patients (23%) needed second-line treatment. Japanese scores had poor performance in our whole population (sensitivity 14-61%). On multivariate regression analysis, predictors of secondary treatment after initial IVIG were hepatomegaly, ALT level ≥30 IU/L, lymphocyte count <2400/mm 3 and time to treatment <5 days. The best sensitivity (77%) and specificity (60%) of this model was with 1 point per variable and cutoff ≥2 points. The sensitivity remained good in our 3 main ethnic subgroups (74-88%). We identified predictors of IVIg resistance and built a new score with good sensitivity and acceptable specificity in a non-Asian population. Kawasaki disease (KD) is the leading cause of acquired heart disease in childhood in developed countries 1. The level of coronary artery involvement mainly determines the prognosis of this systemic vasculitis affecting predominantly young children, although pericarditis, myocarditis and valvular dysfunction are not uncommon 1,2. Occasionally, KD can be complicated during the acute phase by shock syndrome 3 , macrophage activation syndrome 4 , or myocardial infarction 1. Although the mortality rate is relatively low during the acute phase, sudden death due to myocardial ischemia could occur many years later in children or adults with coronary artery sequelae 1. The efficacy of early treatment with intravenous immunoglobulin (IVIg) is well established 5,6 and has reduced the prevalence of coronary artery abnormalities (CAAs) from 26-30% to 2.5-5% at 1 month after disease onset 6,7. However, 30% to 40% of KD patients develop coronary dilatations within the first days of the disease 8. In addition,

Objective. Anakinra has been shown to be successful in preventing and treating cardiovascular lesions both in experimental murine models of Kawasaki disease (KD) and in several studies of intravenous immunoglobulin (IVIG)and steroid-resistant patients with KD. This study was undertaken to determine the safety of blocking interleukin-1 in patients with IVIG-resistant KD. Methods. Sixteen patients were included in the present study. Patients with KD who were not responsive to 1 or more courses of 2 mg/kg of IVIG received anakinra by subcutaneous daily injections. The starting dose was 2 mg/kg of anakinra (4 mg/kg in patients who were age <8 months and who weighed ≥5 kilograms), and the dose was increased up to 6 mg/kg every 24 hours if the patient's body temperature remained >38°C, indicative of a fever. Treatment duration was 14 days. The last visit was on day 45. The primary outcome was abatement of fever. Secondary outcome measures included disease activity, coronary artery Z score, and C-reactive protein (CRP) levels. Results. Seventy-five percent of the patients in the intent-to-treat group and 87.5% in the per-protocol group became afebrile within 48 hours of the last escalation dose of anakinra. Reduction of disease activity by 50% was indicated on 93.3% of physician evaluations (95% confidence interval [95% CI] 68.1-99.8%) and on 100% of parent evaluations (95% CI 73.5-100%) of parent evaluations. CRP values normalized by day 30. At the initial screening, 12 of 16 patients had a maximum coronary artery Z score of >2, and 10 of 16 patients had a maximum Z score of >2.5. On day 45, 5 of 10 patients (50% [95% CI 18.7-81.3%]) and 6 of 12 patients (50% [95% CI 21.1-78.9%]) had achieved coronary artery Z scores of <2.5 and <2, respectively. Five serious adverse events were observed in 3 patients, but no serious infections or deaths occurred. Conclusion. Anakinra was well tolerated in the study patients and may have some efficacy in reducing fever, markers of systemic inflammation, and coronary artery dilatation in individuals with IVIG-refractory KD.

Taken together, these results may support EC use in severe STEC-HUS patients, especially those presenting severe neurological symptoms. The study, however, is limited by absence of a control group and use of multiple therapeutic interventions in treatment groups. Thus, prospective, controlled trials should be undertaken.

Taken together, these results showed that serum Gd-IgA1 and urinary IgA, IgG, IgM, NGAL, IL-1β, IL-6, IL-8, IL-10, IgA-IgG and IgA-sCD89 complexes were associated with nephritis in IgAV patients. Urinary IgA level may improve patient risk stratification for poor outcome.