Myeloid dendritic cells are primed in allergic asthma for thymic stromal lymphopoietin-mediated induction of Th2 and Th9 responses

BACKGROUND

Type 1 myeloid dendritic cells (mDCs) contribute to inception of allergic asthma (AA) and are regulated by epithelial-derived cytokines.

OBJECTIVES

To evaluate whether mDCs from AA patients are primed for thymic stromal lymphopoietin (TSLP)-driven responses.

METHODS

mDCs from 18 AA patients and 15 controls were purified using immunomagnetic sorting. Cells were pulsed with TSLP or Dermatophagoides pteronyssinus (Der p) allergen, before FACS phenotyping and co-culture with allogeneic CD4+ T cells. Bronchial biopsies from 15 AA patients and four controls were immunostained for CD1c and TSLP receptor (TSLPR).

RESULTS

Allergic asthma patients had a higher proportion of TSLPR+ mDCs, in blood and bronchial mucosa. When compared to mDCs from controls, both TSLP- and Der p-pulsed blood mDCs from AA patients induced increased polarization of CD4+ T cells into Th2 cells (IL-5, IL-13, and GATA3+), while only TSLP-mDCs promoted Th9 cells (IL-9 and PU.1+ /IRF4+). In addition, OX40L was induced upon TSLP stimulation and was required for the induction of Th2, but not Th9, cells. In contrast, development of Th9 cells in this model depended on TGF-β1.

CONCLUSIONS

Our data indicate overlapping but partially distinct effects of TSLP and Der p allergen pathways, showing that DCs are primed in human asthma for TSLP-driven induction of both Th2 and Th9 cells. This novel TSLP/mDC/Th9 axis operates through a distinct, OX40L-independent pathway. These data further highlight the TSLP pathway as a relevant target in human asthma.

The role of transforming growth factor-β1 in airway inflammation of childhood asthma

TGF-beta-targeting structural and inflammatory cells has been implicated in the mechanisms leading to the inflammatory and restructuring processes in asthma, suggesting an impact of TGF-beta1 signaling on the development and persistency of this disease. We investigated the potential early involvement of TGF-beta1 activity in the immunological and molecular mechanisms underlying progression of inflammation in childhood asthma. We evaluated the levels of TGF-beta1 in induced sputum supernatants (ISSs) and the expression of small mother cell against decapentaplegic (Smad) 2 and Smad7 proteins in induced sputum cells (ISCs) from children with intermittent asthma (IA), moderate asthma (MA) and control subjects (C). Furthermore, we investigated the regulatory role of TGF-beta1 activity on eosinophil and neutrophil adhesion to epithelial cells using adhesion assay, and on the granulocyte expression of adhesion molecule CD11b/CD18 Macrophage-1 antigen (MAC-1), by flow cytometry. We found that the levels of TGF-beta1 are increased in ISSs of IA and MA in comparison to C, concomitantly to the activation of intracellular signaling TGFbeta/Smads pathway in ISCs. In MA, TGF-beta1 levels correlated with the number of sputum eosinophils and neutrophils. Furthermore, we showed the ability of sputum TGF-beta1 to promote eosinophil and neutrophil adhesion to epithelial cells, and to increase the expression of MAC-1 on the granulocyte surface. This study shows the activation of TGFbeta/Smad signaling pathway in the airways of children with IA and, despite the regular ICS treatment, in children with MA, and provides evidence for the contribution of TGF-beta1 in the regulation of granulocyte activation and trafficking.

Similar early characteristics but variable neurological outcome of patients with a de novo mutation of KCNQ2

Background

Early onset epileptic encephalopathies (EOEEs) are dramatic heterogeneous conditions in which aetiology, seizures and/or interictal EEG have a negative impact on neurological development. Several genes have been associated with EOEE and a molecular diagnosis workup is challenging since similar phenotypes are associated with mutations in different genes and since mutations in one given gene can be associated with very different phenotypes. Recently, de novo mutations in KCNQ2, have been found in about 10% of EOEE patients. Our objective was to confirm that KCNQ2 was an important gene to include in the diagnosis workup of EOEEs and to fully describe the clinical and EEG features of mutated patients.

Methods

We have screened KCNQ2 in a cohort of 71 patients with an EOEE, without any brain structural abnormality. To be included in the cohort, patient’s epilepsy should begin before three months of age and be associated with abnormal interictal EEG and neurological impairment. Brain MRI should not show any structural abnormality that could account for the epilepsy.

Results

Out of those 71 patients, 16 had a de novo mutation in KCNQ2 (23%). Interestingly, in the majority of the cases, the initial epileptic features of these patients were comparable to those previously described in the case of benign familial neonatal epilepsy (BFNE) also caused by KCNQ2 mutations. However, in contrast to BFNE, the interictal background EEG was altered and displayed multifocal spikes or a suppression-burst pattern. The ongoing epilepsy and development were highly variable but overall severe: 15/16 had obvious cognitive impairment, half of the patients became seizure-free, 5/16 could walk before the age of 3 and only 2/16 patient acquired the ability to speak.

Conclusion

This study confirms that KCNQ2 is frequently mutated de novo in neonatal onset epileptic encephalopathy. We show here that despite a relatively stereotyped beginning of the condition, the neurological and epileptic evolution is variable.

Benign hereditary chorea: phenotype, prognosis, therapeutic outcome and long term follow-up in a large series with new mutations in the TITF1/NKX2-1 gene

BACKGROUND

Benign hereditary chorea (BHC) is a rare autosomal dominant disorder characterised by childhood onset that tends to improve in adulthood. The associated gene, NKX2-1 (previously called TITF1), is essential for organogenesis of the basal ganglia, thyroid and lungs. The aim of the study was to refine the movement disorders phenotype. We also studied disease course and response to therapy in a large series of genetically proven patients.

METHODS

We analysed clinical, genetic findings and follow-up data in 28 NKX2-1 mutated BHC patients from 13 families.

RESULTS

All patients had private mutations, including seven new mutations, three previously reported mutations and three sporadic deletions encompassing the NKX2-1 gene. Hypotonia and chorea were present in early infancy, with delayed walking ability (25/28); dystonia, myoclonus and tics were often associated. Attention deficit hyperactivity disorder (ADHD) was present in seven. Among the 14 patients followed-up until adulthood, nine had persistent mild chorea, two had near total resolution of chorea but persistent disabling prominent myoclonus and three recovered completely. Learning difficulties were observed in 20/28 patients, and three had mental retardation. Various combinations of BHC, thyroid (67%) and lung (46%) features were noted. We found no genotype-phenotype correlation. A rapid and sustained beneficial effect on chorea was obtained in 5/8 patients treated with tetrabenazine.

CONCLUSION

Early onset chorea preceded by hypotonia is suggestive of BHC. Associated thyroid or respiratory disorders further support the diagnosis and call for genetic studies. Tetrabenazine may be an interesting option to treat disabling chorea.

PRRT2 mutations: a major cause of paroxysmal kinesigenic dyskinesia in the European population

OBJECTIVE

Paroxysmal kinesigenic dyskinesia (PKD) is a rare disorder characterized by recurrent attacks of hyperkinetic movements. PKD can be isolated or associated with benign infantile seizures as part of the infantile convulsions with choreoathetosis (ICCA) syndrome. Mutations in the PRRT2 gene were recently identified in patients with PKD and ICCA. We studied the prevalence of PRRT2 mutations and characteristics of the patients in a European population of patients with PKD and ICCA.

METHODS

Patients were recruited through the 1996-2011 database of our DNA bank, to which physicians refer DNA with a putative diagnosis and clinical information. Two movement disorders experts reviewed the information on patients with a putative diagnosis of PKD. Patients who fulfilled the criteria for PKD and ICCA were included. The PRRT2 coding sequence was analyzed by direct sequencing.

RESULTS

Among 42 index cases of unrelated families referred with a putative diagnosis of PKD, a total of 34 patients, including 32 with isolated PKD and 2 with ICCA, were selected for genetic analysis. Mutations introducing premature termination codons were identified in 22 of 34 patients including 13 of 14 families and 9 of 20 patients with sporadic cases. The previously described c.649dupC/pArg217ProfsX8 and c.629dupC/pAla211SerfsX14 were present, respectively, in 17 patients and 1 patient; we also report 3 novel mutations: c.649delC/pArg217GlufsX12 in 2 patients, and c.562C>T/pGln188X and c.649C>T/pArg217X, each in 1 patient. The group with mutations was characterized by a younger age at onset (9 years) compared with the patients without mutations (15 years; p < 0.01).

CONCLUSION

Mutations in PRRT2 are a major cause of PKD in familial and sporadic cases in the European population.

[Mechanotransduction and the bronchoalveolar epithelium]

The bronchoalveolar epithelium is submitted to numerous mechanical strains. These strains induce a specific cellular activity at the tissue level. This type of activation has been studied in respiratory medicine, mainly in the context of mechanical ventilation and asthma. The phenomenon of mechanotransduction is linked to various epithelial cellular activities such as epithelium repair, extracellular matrix remodelling, inflammatory mediator release and mucociliary regulation. In this review, the main studies related to bronchoalveolar epithelial mechanotransduction are reported to bring a new perspective on this little known biological phenomenon. A better understanding of the physiological and pathological aspects will potentially offer new treatment approaches for bronchial diseases.

Upper airway x 1: allergic rhinitis and asthma: united disease through epithelial cells

The relationship between allergic rhinitis and asthma is now established, and most of the clinical, epidemiological and biological data recommend integrated management. Epithelial cells represent the first barrier of the upper and lower respiratory tracts and thus are logical targets for a comprehensive integrated therapeutic approach. This review discusses rhinosinusitis as a co-morbid condition, a precipitating or triggering condition, and an epiphenomenon as an integrated part of the disease. A better understanding and a more pragmatic method of diagnosis and management is needed using cost-effective long-term strategies.

Incidence of paroxysmal atrial tachycardias in patients treated with cardiac resynchronization therapy and continuously monitored by device diagnostics

AIMS

Little is known about the incidence of paroxysmal atrial tachycardias (PAT) in patients with heart failure (HF). The availability of cardiac resynchronization therapy (CRT) devices with extended diagnostics for AT enables continuous monitoring of PAT episodes. The aim of the study was to assess the incidence over time of PAT in HF patients treated with CRT.

METHODS AND RESULTS

Consecutive patients in NYHA functional class III or IV despite optimal drug therapy, QRS duration > or = 130 ms, left ventricular ejection fraction < or = 35%, and left ventricular end-diastolic dimension > or = 55 mm were eligible for enrolment. Patients with permanent or persistent atrial fibrillation (AF) were not included in the study. The first follow-up examination was performed 2 weeks after implantation, to optimize atrial sensing and CRT. Subsequent follow-up examinations were carried out 15 and 28 weeks after implantation, to collect the telemetric data. A total of 173 patients (67 +/- 11 years, M 116) were enrolled. Complete arrhythmia monitoring data were available from 120 patients over a mean follow-up of 183 +/- 23 days. Atrial tachycardia episodes were detected through telemetry in 25 of 120 patients (21%) during at least one follow-up examination. Atrial tachycardia episodes were recorded in 29 and 17% (P = NS) of patients with and without previous history of AF, respectively.

CONCLUSION

More than 20% of the overall HF patient population treated with CRT suffer PAT episodes. Paroxysmal atrial tachycardia may interfere with response to CRT. Therefore, telemetric data may be relevant to drive the appropriate therapy in each patient.