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IntroductionIn the peripheral lymphoid tissues of normal mice and humans, 1% to 5% of ␣␤ T-cell receptor-positive (TCR ϩ ) T cells are CD4 Ϫ CD8 Ϫ (double-negative [DN]) T cells. 1,2 MRL/Mpj-lpr/lpr mice have a mutant Fas gene and a massive lymphadenopathy consisting of an age-related accumulation of DN ␣␤TCR ϩ T cells. 3,4 The DN T cells have been shown to possess the capacity to regulate auto-and alloimmune responses and induce immune tolerance. [5][6][7][8] However, the origin of peripheral DN T cells is still unclear. The heterogeneity of DN T-ells in the expression of surface markers suggests that several maturation/differentiation pathways may exist. In murine models, several studies have demonstrated that DN ␣␤ TCR ϩ T cells can be derived directly from CD8 ϩ T cells. [9][10][11][12] Other studies suggest that DN ␣␤ TCR ϩ natural killer T cells (NKT cells) arise extrathymically from bone marrow (BM). 13 More recently, Ford et al reported that DN T regulatory cells can develop outside the thymus, but not from mature CD8 ϩ T-cell precursors. 14 However, a differentiation pathway of peripheral DN T cells from CD4 ϩ T cells was not identified.In this report, we monitored CD4 expression during CD4 ϩ T-cell proliferation and differentiation and identified a new pathway for the generation of a DN regulatory T-cell subset. This pathway uncovered a new intrinsic homeostatic mechanism that regulates the magnitude of immune responses to alloantigen both in vitro and in vivo. Our observations will permit the development of novel, cell-based, therapeutic approaches for the prevention of allograft rejection and for the treatment of autoimmune diseases. Materials and methodsMice Male C57BL/6 (H-2 b ), C57BL/6 congenic for CD45.1, C57BL/6 TEa TCR-transgenic, C57BL/6 perforin gene knock-out (KO), C57BL/6 RAG Ϫ/Ϫ , DBA/2 (H-2 d ), C3H (H-2 k ), and B6D2F1 (H-2 b/d ) mice were obtained from The Jackson Laboratory (Bar Harbor, ME). Foxp3 gfp knock-in C57BL/6 mice were provided by Dr Wenda Gao (Boston, MA). 15 All mice were maintained in the animal facilities of Harvard Institutes of Medicine. Reagents and antibodiesRecombinant mouse interleukin-2 (IL-2), IL-4, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were obtained from Biosource (Camarillo, CA). CD4 ϩ T-cell enrichment column, T-cell enrichment column, and recombinant mouse IL-15 were obtained from R&D Systems (Minneapolis, MN). Fluorochrome-conjugated antibodies to mouse CD3, CD4, CD8, CD25, CD28, CD40, CD44, CD45.1, CD69, CD86, Ter119, B220, CD11b, CD11c, Gr1, NK1.1, TCR␤, TCR␥␦, and isotype controls were obtained from eBioscience (San Diego, CA). Annexin V-PE was purchased from BD Pharmingen (San Diego, CA). CD4 ϩ CD25 ϩ regulatory T cell (Treg) isolation kits, anti-PE microbeads, and magnetic bead separation columns were obtained from Miltenyi Biotec (Auburn, CA). Mitomycin C was obtained from Sigma (St Louis, MO).Purification of CD4 ؉ , CD4 ؉ CD25 ؉ , CD4 ؉ CD25 ؊ , and CD4 ؊ CD8 ؊ DN T cellsSingle-cell suspensions were prepared from the spleens and...

T cell Ig mucin (Tim) molecules modulate CD4 + T cell responses. In keeping with the view that Tim-1 generates a stimulatory signal for CD4 + T cell activation, we hypothesized that an agonist Tim-1-specific mAb would intensify the CD4 + T cell-dependant allograft response. Unexpectedly, we determined that a particular Tim-1-specific mAb exerted reciprocal effects upon the commitment of alloactivated T cells to regulatory and effector phenotypes. Commitment to the Th1 and Th17 phenotypes was fostered, whereas commitment to the Treg phenotype was hindered. Moreover, ligation of Tim-1 in vitro effectively deprogrammed Tregs and thus produced Tregs unable to control T cell responses. Overall, the effects of the agonist Tim-1-specific mAb on the allograft response stemmed from enhanced expansion and survival of T effector cells; a capacity to deprogram natural Tregs; and inhibition of the conversion of naive CD4 + T cells into Tregs. The reciprocal effects of agonist Tim-1-specific mAbs upon effector T cells and Tregs serve to prevent allogeneic transplant tolerance.

Background Spinal cord injury (SCI) patients display disruption of gut microbiome, and gut dysbiosis exacerbate neurological impairment in SCI models. Cumulative data support an important role of gut microbiome in SCI. Here, we investigated the hypothesis that fecal microbiota transplantation (FMT) from healthy uninjured mice into SCI mice may exert a neuroprotective effect. Results FMT facilitated functional recovery, promoted neuronal axonal regeneration, improved animal weight gain and metabolic profiling, and enhanced intestinal barrier integrity and GI motility in SCI mice. High-throughput sequencing revealed that levels of phylum Firmicutes, family Christensenellaceae, and genus Butyricimonas were reduced in fecal samples of SCI mice, and FMT remarkably reshaped gut microbiome. Also, FMT-treated SCI mice showed increased amount of fecal short-chain fatty acids (SCFAs), which correlated with alteration of intestinal permeability and locomotor recovery. Furthermore, FMT downregulated IL-1β/NF-κB signaling in spinal cord and NF-κB signaling in gut following SCI. Conclusion Our study demonstrates that reprogramming of gut microbiota by FMT improves locomotor and GI functions in SCI mice, possibly through the anti-inflammatory functions of SCFAs.

ObjectivesTo evaluate the risk factors for rupture of intracranial aneurysms (IAs) using high resolution MRI (HRMRI).Methods91 consecutive patients with 106 IAs were reviewed from February 2016 to April 2017. Patients and IAs were divided into ruptured and unruptured groups. In addition to the clinical characteristics of the patients, the features of IAs (eg, shape) were evaluated by CT angiography, whereas wall thickness, enhanced patterns, and enhancement ratio (ER) were evaluated by MRI. Multiple logistic regression analysis was used to identify independent risk factors associated with the rupture of IAs. Receiver operating characteristic curve analysis was performed on the final model, and the optimal thresholds were obtained.ResultsER (OR 6.638) and partial wall enhancement (PWE) (OR 6.710) were not markers of aneurysms more prone to rupture, but simply were more commonly found in the ruptured aneurysm cohort. The threshold value for ER was 61.5%.ConclusionsER (≥61.5%) and IAs with PWE are better predictors of rupture. Increased attentions should be paid to these factors during assessment of IA rupture.

Background and Aim We aimed to estimate the worldwide incidence and prevalence, with focus on the geographical differences and temporal trends. Methods Studies on epidemiology of primary biliary cholangitis (PBC) in PubMed, Embase, and Cochrane Library were systematically retrieved from inception to October 2, 2020. Random‐effect model was applied to estimate the pooled PBC incidence and prevalence rates. Subgroup analysis, meta‐regression, and sensitivity analysis were conducted to find out the cause for heterogeneity. Results Out of 3974 records identified through database searching, 47 population‐based studies were finally included. The pooled global incidence and prevalence of PBC were 1.76 and 14.60 per 100 000 persons, respectively. Both the PBC incidence and prevalence were lower in the Asia‐Pacific region (0.84, 9.82 per 100 000 persons) than that in North America (2.75, 21.81 per 100 000 persons) and Europe (1.86, 14.59 per 100 000 persons) (P < 0.05). The incidence and prevalence showed an increasing tendency in all three regions, with the fastest growth of prevalence in North America (P < 0.05). We found a similar incidence and a lower prevalence of PBC in Northern Europe than that in Southern Europe. A higher incidence and prevalence were observed in female individuals and in the elderly (60–79). Conclusion The PBC incidence and prevalence varied widely across regions, with North America being the highest, followed by Europe, and the lowest in the Asia‐Pacific region. Both the incidence and prevalence showed an increasing tendency worldwide, especially in North America.

Background and Purpose— The study goal was to evaluate cerebral perfusion in moyamoya patients with a novel staging system and investigate the association between differences of perfusion status and clinical outcomes in patients treated with revascularization. Methods— About 506 consecutive patients from 2009 to 2015 were enrolled. The perfusion status was evaluated by a staging system-the stage of preinfarction period based on the result of computed tomography perfusion. Hemisphere in different perfusion stage was compared between hemorrhagic patients (n=155) and ischemic patients (n=351). The modified Rankin Scale was applied to evaluate the prognosis of patients. Results— In the enrolled 506 patients: 229 hemispheres (22.6%) with normal perfusion, 72 hemispheres (7.1%) in stage I, 205 hemispheres (20.3%) in stage II, 308 hemispheres (30.4%) in stage III, and 198 hemispheres (19.6%) in stage IV. Significant difference was observed in stage distribution between hemorrhagic patients and ischemic patients ( P <0.01). The ratio of hemispheres with normal perfusion in hemorrhagic group is more than the ischemic group ( P <0.05; odds ratio, 1.440; 95% CI, 1.144–1.811). The ratio of hemispheres in stage III in ischemic group is more than the hemorrhagic group ( P <0.01; odds ratio, 0.618, 95% CI, 0.487–0.783). In the prognosis-related analysis, the stage I group has the highest improved ratio (73.9%) and the normal perfusion group has the lowest improved ratio (33.3%). The improved ratio has a decreasing tendency from stage I to stage IV. Conclusions— The novel preinfarction staging system is a valuable assessment tool to evaluate cerebral perfusion status in moyamoya patients and predict the efficacy of revascularization. Ischemic patients suffer more from hypoperfusion. Patients in stage I and stage II are more likely to obtain improvement after revascularization. This is a retrospective study.

Despite the development of successful immunosuppression protocols and tremendous improvement in short-term graft survival rates, the problem of chronic graft loss remains the bane of clinical transplantation. The induction and maintenance of transplantation tolerance is the “Holy grail” of transplantation. The recent identification and characterization of regulatory T cells (T regs) has opened up exciting opportunities for tolerance induction, immunotherapy and immunomodulation in transplantation. This review focuses on current understanding of regulatory T cells and their role in transplantation tolerance.