SummaryWe demonstrate that mouse intestinal intraepithelial lymphocytes (IEL) can be divided into subsets based on the differential expression of functional T cell receptor r signaling complexes. Two subsets, CD4+8c~+fl -and CD8oL+~ -, are refractory to stimulation with anti-TCR-a/fl and contain high frequencies of potentially self-reactive cells. In contrast, the CD4 + and CD8a +B + IEL subsets are responsive to anti-TCR-o~/fl and depleted of potentially selfreactive cells. The analysis of fetal liver radiation chimeras using adult thymectomized recipients demonstrates that the four TCR-odB + IEL subsets are generated in normal numbers in the absence of the thymus. Moreover, expression of the major histocompatibility complex class II-encoded I-E molecule and Mlsl ~ in the gut of the athymic host results in the negative selection of potentially stir-reactive T cells expressing V/~11 and V/~6, respectively, from those IEL subsets that express functional TCR-cr signaling complexes. Neither the spleen nor the Peyer's patches of athymic recipients contain T cells of donor origin. In contrast, normal numbers of phenotypically and functionally mature CD4 + and CD8c~+fl + T cells of donor origin are found in the lamina propria of chimeric animals. The phenotypic analysis of lymphocytes obtained from Ly5 congenic parabionts reveals that peripheral T cells migrate rapidly to the Peyer's patches and lamina propria, but not to the intestinal epithelium. Taken together, these results demonstrate that the intestinal epithelium is a thymus-independent site of T lymphopoiesis, where selection of the T cell repertoire involves the deletion of potentially self-reactive cells in situ. Moreover, the appearance of donor-derived, phenotypically mature T ceils, exclusively in the lamina propria of athymic radiation chimeras, suggests that mature IEL expressing functional TCR-o~/fl migrate to this site.

Skeletal muscle atrophy in individuals with advanced chronic obstructive pulmonary disease (COPD) is associated with diminished quality of life, increased health resource use, and worsened survival. Muscle wasting results from an imbalance between protein degradation and synthesis, and is enhanced by decreased regenerative repair. We investigated the activation of cellular signaling networks known to mediate muscle atrophy and regulate muscle regenerative capacity in rodent models, in individuals with COPD (FEV(1) < 50% predicted). Nine patients with COPD and nine control individuals were studied. Quadriceps femoris muscle isometric contractile force and cross-sectional area were confirmed to be significantly smaller in the patients with COPD compared with control subjects. The vastus lateralis muscle was biopsied and muscle transcript and/or protein levels of key components of ubiquitin-mediated proteolytic systems (MuRF1, atrogin-1, Nedd4), inflammatory mediators (IkappaBalpha, NF-kappaBp65/p50), AKT network (AKT, GSK3beta, p70S6 kinase), mediators of autophagy (beclin-1, LC3), and myogenesis (myogenin, MyoD, Myf5, myostatin) were determined. Atrogin-1 and Nedd4, two ligases regulating ubiquitin-mediated protein degradation and myostatin, a negative regulator of muscle growth, were significantly increased in the muscle of patients with COPD. MuRF1, Myf5, myogenin, and MyoD were not differentially expressed. There were no differences in the level of phosphorylation of AKT, GSK3beta, p70S6kinase, or IkappaBalpha, activation of NF-kappaBp65 or NF-kappaBp50, or level of expression of beclin-1 or LC3, suggesting that AKT signaling was not down-regulated and the NF-kappaB inflammatory pathway and autophagy were not activated in the COPD muscle. We conclude that muscle atrophy associated with COPD results from the recruitment of specific regulators of ubiquitin-mediated proteolytic pathways and inhibition of muscle growth.

The predictive power of coefficient b to predict noninjurious ventilatory strategy in a model of acute lung injury is high.

IMPORTANCEThe mortality rate for individuals on the wait list for lung transplant is 15% to 25%, and still only 20% of lungs from multiorgan donors are used for lung transplant. The lung donor pool may be increased by assessing and reconditioning high-risk extended criteria donor lungs with ex vivo lung perfusion (EVLP), with similar short-term outcomes. OBJECTIVE To assess the long-term outcomes of transplant recipients of donor lungs treated with EVLP. DESIGN, SETTING, AND PARTICIPANTS This retrospective cohort single-center study was conducted from August 1, 2008, to February 28, 2017, among 706 recipients of donor lungs not undergoing EVLP and 230 recipients of donor lungs undergoing EVLP. EXPOSURE Donor lungs undergoing EVLP. MAIN OUTCOMES AND MEASURESThe incidence of chronic lung allograft dysfunction and allograft survival during the 10-year EVLP era were the primary outcome measures. Secondary outcomes included donor characteristics, maximum predicted percentage of forced expiratory volume in 1 second, acute cellular rejection, and de novo donor-specific antibody development. RESULTSThis study included 706 patients (311 women and 395 men; median age, 50 years [interquartile range, 34-61 years]) in the non-EVLP group and 230 patients (85 women and 145 men; median age, 46 years [interquartile range, 32-55 years]) in the EVLP group. The EVLP group donors had a significantly lower mean (SD) PaO 2 :fraction of inspired oxygen ratio than the non-EVLP group donors (348 [108] vs 422 [88] mm Hg; P < .001), higher prevalence of abnormal chest radiography results (135 of 230 [58.7%] vs 349 of 706 [49.4%]; P = .02), and higher proportion of smoking history (125 of 204 [61.3%] vs 322 of 650 [49.5%]; P = .007). More recipients in the EVLP group received single-lung transplants (62 of 230 [27.0%] vs 100 of 706 [14.2%]; P < .001). There was no significant difference in time to chronic lung allograft dysfunction between the EVLP and non-EVLP group (70% vs 72% at 3 years; 56% vs 56% at 5 years; and 53% vs 36% at 9 years; log-rank P = .68) or allograft survival between the EVLP and non-EVLP groups (73% vs 72% at 3 years; 62% vs 58% at 5 years; and 50% vs 44% at 9 years; log-rank P = .97) between the 2 groups. All secondary outcomes were similar between the 2 groups.CONCLUSIONS AND RELEVANCE Since 2008, 230 of 936 lung transplants (24.6%) in the Toronto Lung Transplant Program were performed after EVLP assessment and treatment. Use of EVLP-treated lungs led to an increase in the number of patients undergoing transplantation, with comparable long-term outcomes.

Donor‐specific HLA antibodies (DSA) have an adverse effect on short‐term and long‐term lung transplant outcomes. We implemented a perioperative strategy to treat DSA‐positive recipients, leading to equivalent rejection and graft survival outcomes. Pretransplant DSA were identified to HLA‐A, B, C, DR and DQ antigens. DSA‐positive patients were transplanted if panel reactive antibody (PRA) ≥30% or medically urgent and desensitized with perioperative plasma exchange, intravenous immune globulin, antithymocyte globulin (ATG), and mycophenolic acid (MPA). PRA‐positive/DSA‐negative recipients received MPA. Unsensitized patients received routine cyclosporine, azathioprine and prednisone without ATG. From 2008–2011, 340 lung‐only first transplants were performed: 53 DSA‐positive, 93 PRA‐positive/DSA‐negative and 194 unsensitized. Thirty‐day survival was 96 %/99%/96% in the three groups, respectively. One‐year graft survival was 89%/88%/86% (p = 0.47). DSA‐positive and PRA‐positive/DSA‐negative patients were less likely to experience any ≥ grade 2 acute rejection (9% and 9% vs. 18% unsensitized p = 0.04). Maximum predicted forced expiratory volume (1 s) (81%/74%/76%, p = NS) and predicted forced vital capacity (81%/77%/78%, respectively, p = NS) were equivalent between groups. With the application of this perioperative treatment protocol, lung transplantation can be safely performed in DSA/PRA‐positive patients, with similar outcomes to unsensitized recipients.