IL-7R signaling in regulatory T cells maintains peripheral and allograft tolerance in mice.

Foxp3(+)CD4(+) regulatory T cells (Treg) have a crucial role in controlling CD4(+) T-cell activation, proliferation, and effector function. However, the molecular mechanisms regulating Treg function remain poorly understood. Here we assessed the role of IL-7, a key cytokine regulating T-cell homeostasis, in suppressor capacity of Treg. Using a skin allograft model in which transplant acceptance is controlled by the number of transferred Treg, we find that Treg impair the proliferation of allogeneic CD4(+) T cells, decrease production of IFNγ by effector T cells, and prevent early and increase late IL-7 induction by lymph node stromal cells. Increased IL-7 availability enhanced Treg survival, stabilized Treg molecular signature, enhanced surface IL-2Rα expression, and improved IL-2 binding of Treg, which diminished proliferation of alloreactive CD4(+) T cells. Sequestration of IL-7 or impairment of IL-7R signaling after allograft transplantation abolished Treg-mediated tolerance by limiting their suppressive capacity. Aged Il7rα-ΔTreg mice displayed mild symptoms of autoimmunity correlating with impaired expansion of effector Treg in response to IL-2. Thus, IL-7R signaling on Treg supports the functional activity of effector Treg by increasing their IL-2 sensitivity in the lymph node during peripheral and allograft tolerance.

Copeptin as a serum biomarker of febrile seizures.

BACKGROUND AND OBJECTIVES: Accurate diagnosis of febrile seizures in children presenting after paroxysmal episodes associated with fever, is hampered by the lack of objective postictal biomarkers. The aim of our study was to investigate whether FS are associated with increased levels of serum copeptin, a robust marker of arginine vasopressin secretion. METHODS: This was a prospective emergency-setting cross-sectional study of 161 children between six months and five years of age. Of these, 83 were diagnosed with febrile seizures, 69 had a febrile infection without seizures and nine had epileptic seizures not triggered by infection. Serum copeptin and prolactin levels were measured in addition to standard clinical, neurophysiological, and laboratory assessment. CLINICAL TRIAL REGISTRATION: NCT01884766. RESULTS: Circulating copeptin was significantly higher in children with febrile seizures (median [interquartile range] 18.9 pmol/L [8.5-36.6]) compared to febrile controls (5.6 pmol/L [4.1-9.4]; p < 0.001), with no differences between febrile and epileptic seizures (21.4 pmol/L [16.1-46.6]; p = 0.728). In a multivariable regression model, seizures were the major determinant of serum copeptin (beta 0.509; p < 0.001), independently of clinical and baseline laboratory indices. The area under the receiver operating curve for copeptin was 0.824 (95% CI 0.753-0.881), significantly higher compared to prolactin (0.667 [0.585-0.742]; p < 0.001). The diagnostic accuracy of copeptin increased with decreasing time elapsed since the convulsive event (at 120 min: 0.879 [0.806-0.932] and at <60 min: 0.975 [0.913-0.997]). CONCLUSIONS: Circulating copeptin has high diagnostic accuracy in febrile seizures and may be a useful adjunct for accurately diagnosing postictal states in the emergency setting.

Long-term outcome and tolerability of the ketogenic diet in drug-resistant childhood epilepsy--the Austrian experience.

PURPOSE: To evaluate the long-term efficacy/tolerability of the ketogenic diet (KD) in paediatric drug-resistant epilepsies. METHODS: Data from children who were treated between 1999 and 2008 and had continuous follow-up of at least 6 months after initiation of the KD were analysed retrospectively. Response was defined as > or = 50% seizure reduction. Treatment effects on EEG, developmental outcome and the "outcome-predictive" value of various clinical factors were also assessed. RESULTS: 50 children (22 boys; mean age 4.5 years+/-3.55) were included. Mean follow-up was 3.93+/-2.95. 50% of the patients were responders, 48% of them became seizure free. 50% were non-responders, 20% of them deteriorated. In responders, EEG background activity improved significantly (p=0.014) and a significantly lower rate of epileptic discharges (p=0.009) was seen after 6 months. In addition, neurological examination findings demonstrated significant developmental progress (p=0.038). Favourable treatment outcome was associated with a shorter disease duration (p=0.025) and generalised tonic clonic seizures (p=0.059). No further significant outcome predictors were detected. However, response was 44% in patients with infantile spasms, 62.5% in those with Dravet syndrome and 50% in Lennox-Gastaut-syndrome. Side effects occurred in 28%, but discontinuation of the KD was not required in any case. They most often observed with concomitant topiramate (p=0.001) and valproate (p=0.046). CONCLUSION: Despite the retrospective nature of the study and the inhomogeneous patient sample, we found good long-term effects of the KD on seizure frequency, EEG and neurological development.