Characterization and functional studies of forkhead box protein 3− lymphocyte activation gene 3+ CD4+ regulatory T cells induced by mucosal B cells

The induction of mucosal tolerance has been demonstrated to be an effective therapeutic approach for the treatment of allergic diseases. Our previous study demonstrated that Peyer''s patch B cells could convert naive T cells into regulatory T cells (so-called T_reg-of-B(P) cells); however, it is important to characterize this particular subset of T_reg-of-B cells for future applications. This study aimed to investigate the role of lymphocyte activating gene 3 (LAG3) in mediating the regulatory function of T_reg-of-B(P) cells induced by mucosal follicular B (FOB) cells. Microarray analysis and real-time polymerase chain reaction (PCR) were used to assess the gene expression pattern of T_reg-of-B(P) cells. To evaluate the role of LAG3, the in-vitro suppressive function and the alleviation of airway inflammation in a murine model of asthma was assessed. Our data indicated that FOB cells isolated from Peyer''s patches had the ability to generate more suppressive T_reg-of-B cells with LAG3 expression, compared with CD23^loCD21^lo B cells. LAG3 is not only a marker for T_reg-of-B(P) cells, but also participate in the suppressive ability. Moreover, CCR4 and CCR6 could be detected on the LAG3⁺, not LAG3⁻, T_reg-of-B(P) cells and would help cells homing to allergic lung. In the murine model of asthma, the adoptive transfer of LAG3⁺ T_reg-of-B(P) cells was able to sufficiently suppress T helper type 2 (Th2) cytokine production, eosinophil infiltration and alleviate asthmatic symptoms. LAG3 was expressed in T_reg-of-B(P) cells and was also involved in the function of T_reg-of-B(P) cells. In the future, this particular subset of T_reg-of-B cells might be used to alleviate allergic symptoms.     

Viridans Streptococci in Peritoneal Dialysis Peritonitis: Clinical Courses and Long-Term Outcomes

♦ Background:

The clinical courses and long-term outcomes of viridans streptococcus (VS) peritoneal dialysis (PD) peritonitis remain unclear.

♦ Methods:

We conducted a retrospective analysis of all PD patients in a single center with gram-positive cocci (GPC) peritonitis between 2005 and 2011, and divided them into 3 groups: VS, other streptococci and other GPC (apart from VS). Clinical characteristics and outcomes of the VS group were compared with the other streptococci and other GPC groups, with prognostic factors determined.

♦ Results:

A total of 140 patients with 168 episodes of GPC peritonitis (44% of all peritonitis) were identified over 7 years. Among these, 18 patients (13%) developed VS peritonitis, while 14 patients (10%) developed other streptococcal peritonitis. Patients with VS peritonitis had a high cure rate by antibiotic alone (94%), despite a high polymicrobial yield frequency (28%). We found that VS peritonitis carried a lower risk of Tenckhoff catheter removal and relapsing episodes than other GPC peritonitis (6% vs 11%), and a lower mortality than other streptococci peritonitis (0% vs 7%). However, after the index peritonitis episodes, VS, other streptococci, and other GPC group had a significantly increased peritonitis incidence compared with the period before the index peritonitis (all p < 0.01). Patients with VS peritonitis had a significantly higher incidence of refractory peritonitis compared with other streptococci or other GPC peritonitis in the long term (both p < 0.01).

♦ Conclusions:

VS poses a higher risk of subsequent refractory peritonitis after the index episode as compared with other streptococcal or GPC peritonitis. It might be prudent to monitor the technique of these patients with VS peritonitis closely to avoid further peritonitis episodes.     

Genetic mapping of ASIC4 and contrasting phenotype to ASIC1a in modulating innate fear and anxiety

Although ASIC4 is a member of the acid‐sensing ion channel (ASIC) family, we have limited knowledge of its expression and physiological function in vivo. To trace the expression of this ion channel, we generated the ASIC4‐knockout/CreERT²‐knockin (Asic4^CreERT2) mouse line. After tamoxifen induction in the Asic4^CreERT2::CAG‐STOP^floxed‐Td‐tomato double transgenic mice, we mapped the expression of ASIC4 at the cellular level in the central nervous system (CNS). ASIC4 was expressed in many brain regions, including the olfactory bulb, cerebral cortex, striatum, hippocampus, amygdala, thalamus, hypothalamus, brain stem, cerebellum, spinal cord and pituitary gland. Colocalisation studies further revealed that ASIC4 was expressed mainly in three types of cells in the CNS: (i) calretinin (CR)‐positive and/or vasoactive intestine peptide (VIP)‐positive interneurons; (ii) neural/glial antigen 2 (NG2)‐positive glia, also known as oligodendrocyte precursor cells; and (iii) cerebellar granule cells. To probe the possible role of ASIC4, we hypothesised that ASIC4 could modulate the membrane expression of ASIC1a and thus ASIC1a signaling in vivo. We conducted behavioral phenotyping of Asic4^CreERT2 mice by screening many of the known behavioral phenotypes found in Asic1a knockouts and found ASIC4 not involved in shock‐evoked fear learning and memory, seizure termination or psychostimulant‐induced locomotion/rewarding effects. In contrast, ASIC4 might play an important role in modulating the innate fear response to predator odor and anxious state because ASIC4‐mutant mice showed increased freezing response to 2,4,5‐trimethylthiazoline and elevated anxiety‐like behavior in both the open‐field and elevated‐plus maze. ASIC4 may modulate fear and anxiety by counteracting ASIC1a activity in the brain.     

Patterns and severity of vincristine‐induced peripheral neuropathy in children with acute lymphoblastic leukemia

Vincristine, a critical component of combination chemotherapy treatment for pediatric acute lymphoblastic leukemia (ALL), can lead to vincristine‐induced peripheral neuropathy (VIPN). Longitudinal VIPN assessments were obtained over 12 months from newly diagnosed children with ALL (N = 128) aged 1–18 years who received vincristine at one of four academic children's hospitals. VIPN assessments were obtained using the Total Neuropathy Score‐Pediatric Vincristine (TNS©‐PV), National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE©), Balis© grading scale, and Pediatric Neuropathic Pain Scale©–Five (PNPS©‐5). Of children who provided a full TNS©‐PV score, 85/109 (78%) developed VIPN (TNS©‐PV ≥4). Mean TNS©‐PV, grading scale, and pain scores were low. CTCAE©‐derived grades 3 and 4 sensory and motor VIPN occurred in 1.6%/0%, and 1.9%/0% of subjects, respectively. VIPN did not resolve in months 8–12 despite decreasing dose density. VIPN was worse in older children. Partition cluster analysis revealed 2–3 patient clusters; one cluster (n = 14) experienced severe VIPN. In this population, VIPN occurs more commonly than previous research suggests, persists throughout the first year of treatment, and can be severe.     

Altered white matter tract property related to impaired focused attention,sustained attention,cognitive impulsivity and vigilance in attention-deficit/hyperactivity disorder

Background

The neural substrate for clinical symptoms and neuropsychological performance in individuals with attention-deficit/hyperactivity disorder (ADHD) has rarely been studied and has yielded inconsistent results. We sought to compare the microstructural property of fibre tracts associated with the prefrontal cortex and its association with ADHD symptoms and a wide range of attention performance in youth with ADHD and healthy controls.

Methods

We assessed youths with ADHD and age-, sex-, handedness-, coil- and intelligence-matched controls using the Conners’ Continuous Performance Test (CCPT) for attention performance and MRI. The 10 target tracts, including the bilateral frontostriatal tracts (caudate to dorsolateral prefrontal cortex, ventrolateral prefrontal cortex and orbitofrontal cortex), superior longitudinal fasciculus (SLF) and cingulum bundle were reconstructed using diffusion spectrum imaging tractography. We computed generalized fractional anisotropy (GFA) values to indicate tract-specific microstructural property.

Results

We included 50 youths with ADHD and 50 healthy controls in our study. Youths with ADHD had lower GFA in the left frontostriatal tracts, bilateral SLF and right cingulum bundle and performed worse in the CCPT than controls. Furthermore, alteration of the right SLF GFA was most significantly associated with the clinical symptom of inattention in youths with ADHD. Finally, youths with ADHD had differential association patterns of the 10 fibre tract GFA values with attention performance compared with controls.

Limitations

Ten of the youths with ADHD were treated with methylphenidate, which may have long-term effects on microstructural property.

Conclusion

Our study highlights the importance of the SLF, cingulum bundle and frontostriatal tracts for clinical symptoms and attention performance in youths with ADHD and demonstrates the involvement of different fibre tracts in attention performance in these individuals.