Impact of age and telomere length on circulating T cells and rejection risk after lung transplantation for idiopathic pulmonary fibrosis.

BACKGROUND: Most idiopathic pulmonary fibrosis (IPF) lung transplant recipients (IPF-LTRs) have short telomere (ST) length. Inherited mutations in telomere-related genes are associated with the development of T cell immunodeficiency. Despite this, IPF-LTRs with telomere-related rare variants are not protected from acute cellular rejection (ACR). We set out to determine the impact of both age and telomere length on the circulating T cell compartment and ACR burden of IPF-LTRs. METHODS: We identified 106 IPF-LTRs who had telomere length testing using flowFISH (57 with short telomeres and 49 with long telomeres) as well as a subset from both cohorts who had cryopreserved PBMC at least 1 time point, 6 months posttransplantation. Circulating T cells from before transplantation and at 6 and 12 months posttransplantation were analyzed using multiparameter flow cytometry to study phenotype and functional capacity, and bulk T cell receptor sequencing was performed to study repertoire diversity. Linear regression was used to study the relationship of age and telomere length on early (within 1 year) and late (between 1 and 2 years) ACR. RESULTS: IPF-LTRs with ST were found to have premature "aging" of their circulating T cell compartment, with age-agnostic elevations in posttransplant terminal differentiation of CD8+ T cells, increased granzyme B positivity of both CD8+ and CD4+ T cells, upregulation of the exhaustion marker, CD57, and chemotactic protein CCR5, and enhanced T cell receptor clonal expansion. Additionally, we found a significant decline in early ACR burden with increasing age, but only in the ST cohort. CONCLUSIONS: IPF-LTRs with ST have premature "aging" of their circulating T cell compartment posttransplantation and a clear age-related decline in ACR burden.

Lung transplant recipients with telomere-mediated pulmonary fibrosis have increased risk for hematologic complications.

Idiopathic pulmonary fibrosis lung transplant recipients (IPF-LTRs) are enriched for short telomere length (TL) and telomere gene rare variants. A subset of patients with nontransplant short-TL are at increased risk for bone marrow (BM) dysfunction. We hypothesized that IPF-LTRs with short-TL and/or rare variants would be at increased risk for posttransplant hematologic complications. Data were extracted from a retrospective cohort of 72 IPF-LTRs and 72 age-matched non-IPF-LTR controls. Genetic assessment was done using whole genome sequencing or targeted sequence panel. TL was measured using flow cytometry and fluorescence in-situ hybridization (FlowFISH) and TelSeq software. The majority of the IPF-LTR cohort had short-TL, and 26% of IPF-LTRs had rare variants. Compared to non-IPF controls, short-TL IPF-LTRs were more likely to have immunosuppression agents discontinued due to cytopenias (P = .0375), and BM dysfunction requiring BM biopsy was more prevalent (29% vs 4%, P = .0003). IPF-LTRs with short-TL and rare variants had increased requirements for transfusion and growth factor support. Multivariable logistic regression demonstrated that short-TL, rare variants, and lower pretransplant platelet counts were associated with BM dysfunction. Pretransplant TL measurement and genetic testing for rare telomere gene variants identified IPF-LTRs at increased risk for hematologic complications. Our findings support stratification for telomere-mediated pulmonary fibrosis in lung transplant candidates.

Rabbit Antithymocyte Globulin for Treatment of Corticosteroid Refractory Acute Cellular Rejection After Lung Transplantation.

BACKGROUND: Chronic lung allograft dysfunction (CLAD) remains a major cause of death after the first year posttransplant, with acute cellular rejection (ACR) being a major risk factor for CLAD. We evaluated the use of rabbit antithymocyte globulin (rATG) for corticosteroid refractory ACR in lung transplant recipients. METHODS: We retrospectively identified 112 adult lung transplant recipients who received rATG for refractory ACR after lung transplantation. The primary endpoint was the incidence of ACR on follow-up transbronchial biopsy. Secondary endpoints included freedom from ACR within 1 y post-rATG, CLAD progression at 1 y post-rATG, and all-cause mortality at 1 y post-rATG. RESULTS: A complete resolution of ACR was observed in 60.2% of patients, an improvement but not complete resolution in 22.1%, and no response on follow-up biopsy in 17.8%. Mean A grade 1 y post-rATG was 0.51 in complete responders, 1.01 in partial responders, and 2.19 in nonresponders ( P < 0.001). Complete responders had significantly less new or worsening CLAD at 1 y than partial responders (17% versus 40%; P = 0.02). All-cause mortality rate was 14.9% in complete responders, 40% in partial responders, and 30% in nonresponders ( P < 0.01). CONCLUSIONS: rATG appears to be an effective treatment of refractory ACR in lung transplant recipients. Failure to respond to rATG carries an increased risk of early CLAD and death.

Cross-Regulation of F-Box Protein FBXL2 with T-bet and TNF-α during Acute and Chronic Lung Allograft Rejection.

Chronic lung allograft dysfunction is the major barrier to long-term survival in lung transplant recipients. Evidence supports type 1 alloimmunity as the predominant response in acute/chronic lung rejection, but the immunoregulatory mechanisms remain incompletely understood. We studied the combinatorial F-box E3 ligase system: F-box protein 3 (FBXO3; proinflammatory) and F-box and leucine-rich repeat protein 2 (FBXL2; anti-inflammatory and regulates TNFR-associated factor [TRAF] protein). Using the mouse orthotopic lung transplant model, we evaluated allografts from BALB/c → C57BL/6 (acute rejection; day 10) and found significant induction of FBXO3 and diminished FBXL2 protein along with elevated T-bet, IFN-γ, and TRAF proteins 1-5 compared with isografts. In the acute model, treatment with costimulation blockade (MR1/CTLA4-Ig) resulted in attenuated FBXO3, preserved FBXL2, and substantially reduced T-bet, IFN-γ, and TRAFs 1-5, consistent with a key role for type 1 alloimmunity. Immunohistochemistry revealed significant changes in the FBXO3/FBXL2 balance in airway epithelia and infiltrating mononuclear cells during rejection compared with isografts or costimulation blockade-treated allografts. In the chronic lung rejection model, DBA/2J/C57BL/6F1 > DBA/2J (day 28), we observed persistently elevated FBXO3/FBXL2 balance and T-bet/IFN-γ protein and similar findings from lung transplant recipient lungs with chronic lung allograft dysfunction versus controls. We hypothesized that FBXL2 regulated T-bet and found FBXL2 was sufficient to polyubiquitinate T-bet and coimmunoprecipitated with T-bet on pulldown experiments and vice versa in Jurkat cells. Transfection with FBXL2 diminished T-bet protein in a dose-dependent manner in mouse lung epithelial cells. In testing type 1 cytokines, TNF-α was found to negatively regulate FBXL2 protein and mRNA levels. Together, our findings show the combinatorial E3 ligase FBXO3/FBXL2 system plays a role in the regulation of T-bet through FBXL2, with negative cross-regulation of TNF-α on FBXL2 during lung allograft rejection.

CD4+ T-Cell Dysfunction in Severe COVID-19 Disease Is Tumor Necrosis Factor-α/Tumor Necrosis Factor Receptor 1-Dependent.

Rationale: Lymphopenia is common in severe coronavirus disease (COVID-19), yet the immune mechanisms are poorly understood. As inflammatory cytokines are increased in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, we hypothesized a role in contributing to reduced T-cell numbers. Objectives: We sought to characterize the functional SARS-CoV-2 T-cell responses in patients with severe versus recovered, mild COVID-19 to determine whether differences were detectable. Methods: Using flow cytometry and single-cell RNA sequence analyses, we assessed SARS-CoV-2-specific responses in our cohort. Measurements and Main Results: In 148 patients with severe COVID-19, we found lymphopenia was associated with worse survival. CD4+ lymphopenia predominated, with lower CD4+/CD8+ ratios in severe COVID-19 compared with patients with mild disease (P < 0.0001). In severe disease, immunodominant CD4+ T-cell responses to Spike-1 (S1) produced increased in vitro TNF-α (tumor necrosis factor-α) but demonstrated impaired S1-specific proliferation and increased susceptibility to activation-induced cell death after antigen exposure. CD4+TNF-α+ T-cell responses inversely correlated with absolute CD4+ counts from patients with severe COVID-19 (n = 76; R = -0.797; P < 0.0001). In vitro TNF-α blockade, including infliximab or anti-TNF receptor 1 antibodies, strikingly rescued S1-specific CD4+ T-cell proliferation and abrogated S1-specific activation-induced cell death in peripheral blood mononuclear cells from patients with severe COVID-19 (P < 0.001). Single-cell RNA sequencing demonstrated marked downregulation of type-1 cytokines and NFκB signaling in S1-stimulated CD4+ cells with infliximab treatment. We also evaluated BAL and lung explant CD4+ T cells recovered from patients with severe COVID-19 and observed that lung T cells produced higher TNF-α compared with peripheral blood mononuclear cells. Conclusions: Together, our findings show CD4+ dysfunction in severe COVID-19 is TNF-α/TNF receptor 1-dependent through immune mechanisms that may contribute to lymphopenia. TNF-α blockade may be beneficial in severe COVID-19.

Risk factors of bronchial dehiscence after primary lung transplantation.

BACKGROUND: Although the incidence of bronchial dehiscence following lung transplantation has decreased significantly due to improvements in perioperative managements and surgical techniques, it remains a devastating postoperative complication associated with high morbidity and mortality. METHODS: We retrospectively reviewed 811 lung transplantation performed at our institution between January 2011 and December 2020. Bronchial dehiscence was confirmed with flexible bronchoscopy, computed tomography (CT) scan, or clinical findings grade using International Society for Heart and Lung Transplantation recommendations. RESULTS: Bronchial dehiscence was diagnosed in 38 patients (4.7%). The overall survival rates of the patients with bronchial dehiscence were significantly worse than those of the patients without bronchial dehiscence (p = .003). Multivariate analysis identified use of our basiliximab induction protocol (odds ratio = 3.03, p = .008) as an independent predictive factor of postoperative airway dehiscence in our multivariable model, along with total ventilator duration (odds ratio = 1.02, p = .002). CONCLUSIONS: Based on our analysis, patients that underwent our basiliximab induction protocol for lung transplantation experienced a higher rate of postoperative bronchial dehiscence when compared with patients who receive alemtuzumab induction. We believe this may be associated with a higher steroid exposure in this population. Additional studies are necessary to further characterize the relationship between different induction protocols and bronchial dehiscence following transplantation.

Rate of recipient-derived alveolar macrophage development and major histocompatibility complex cross-decoration after lung transplantation in humans.

Alveolar macrophages (AM) play critical roles in lung tissue homeostasis, host defense, and modulating lung injury. The rate of AM turnover (donor AM replacement by circulating monocytes) after transplantation has been incompletely characterized. Furthermore, the anatomic pattern of recipient-derived lung macrophages repopulation has not been reported, nor has their ability to accumulate and present donor major histocompatibility complex (a process we refer to as MHC cross-decoration). We longitudinally characterized the myeloid content of bronchoalveolar lavage (BAL) and biopsy specimens of lung transplant recipients and found a biphasic rate in AM turnover in the allograft, with a rapid turnover perioperatively, accelerated by both the type of induction immunosuppression and the presence of primary graft dysfunction. We found that recipient myeloid cells with cell surface AM phenotype repopulated the lung in a disorganized pattern, comprised mainly of large clusters of cells. Finally, we show that recipient AM take up and present donor peptide-MHC complexes yet are not able to independently induce an in vitro alloreactive response by circulating recipient T cells.

Lung transplantation for idiopathic pulmonary fibrosis enriches for individuals with telomere-mediated disease.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is the most common indication for lung transplantation in North America and variants in telomere-maintenance genes are the most common identifiable cause of IPF. We reasoned that younger IPF patients are more likely to undergo lung transplantation and we hypothesized that lung transplant recipients would be enriched for individuals with telomere-mediated disease due to the earlier onset and more severe disease in these patients. METHODS: Individuals with IPF who underwent lung transplantation or were evaluated in an interstitial lung disease specialty clinic who did not undergo lung transplantation were examined. Genetic evaluation was completed via whole genome sequencing (WGS) of 426 individuals and targeted sequencing for 5 individuals. Rare variants in genes previously associated with IPF were classified using the American College of Medical Genetics guidelines. Telomere length from WGS data was measured using TelSeq software. Patient characteristics were collected via medical record review. RESULTS: Of 431 individuals, 149 underwent lung transplantation for IPF. The median age of diagnosis of transplanted vs non-transplanted individuals was significantly younger (60 years vs 70 years, respectively, p<0.0001). IPF lung transplant recipients (IPF-LTRs) were twice as likely to have telomere-related rare variants compared to non-transplanted individuals (24% vs 12%, respectively, p=0.0013). IPF-LTRs had shorter telomeres than non-transplanted IPF patients (p=0.0028) and >85% had telomeres below the age-adjusted mean. Post-transplant survival and CLAD were similar amongst IPF-LTRs with rare variants in telomere-maintenance genes compared to those without, as well as in those with short telomeres versus longer telomeres. CONCLUSIONS: There is an enrichment for telomere-maintenance gene variants and short telomeres among IPF-LTRs. However, transplant outcomes of survival and CLAD do not differ by gene variants or telomere length within IPF-LTRs. Our findings support individual with telomere-mediated disease should not be excluded from lung transplantation and focusing research efforts on therapies directed toward individuals with short-telomere mediated disease.

Type-1 immunity and endogenous immune regulators predominate in the airway transcriptome during chronic lung allograft dysfunction.

Chronic lung allograft dysfunction (CLAD) remains the major complication limiting long-term survival among lung transplant recipients (LTRs). Limited understanding of CLAD immunopathogenesis and a paucity of biomarkers remain substantial barriers for earlier detection and therapeutic interventions for CLAD. We hypothesized the airway transcriptome would reflect key immunologic changes in disease. We compared airway brush-derived transcriptomic signatures in CLAD (n = 24) versus non-CLAD (n = 21) LTRs. A targeted assessment of the proteome using concomitant bronchoalveolar lavage (BAL) fluid for 24 cytokines/chemokines and alloimmune T cell responses was performed to validate the airway transcriptome. We observed an airway transcriptomic signature of differential genes expressed (DGEs) in CLAD marked by Type-1 immunity and striking upregulation of two endogenous immune regulators: indoleamine 2, 3 dioxygenase 1 (IDO-1) and tumor necrosis factor receptor superfamily 6B (TNFRSF6B). Advanced CLAD staging was associated with a more intense airway transcriptome signature. In a validation cohort using the identified signature, we found an area under the curve (AUC) of 0.77 for CLAD LTRs. Targeted proteomic analyses revealed a predominant Type-1 profile with detection of IFN-γ, TNF-α, and IL-1ß as dominant CLAD cytokines, correlating with the airway transcriptome. The airway transcriptome provides novel insights into CLAD immunopathogenesis and biomarkers that may impact diagnosis of CLAD.

Idiopathic pulmonary fibrosis lung transplant recipients are at increased risk for EBV-associated posttransplant lymphoproliferative disorder and worse survival.

Epstein-Barr virus (EBV)-associated posttransplant lymphoproliferative disorder (EBV-PTLD) is a serious complication in lung transplant recipients (LTRs) associated with significant mortality. We performed a single-center retrospective study to evaluate the risks for PTLD in LTRs over a 7-year period. Of 611 evaluable LTRs, we identified 28 cases of PTLD, with an incidence of 4.6%. Kaplan-Meier analysis showed a decreased freedom from PTLD in idiopathic pulmonary fibrosis (IPF)-LTRs (P < .02). Using a multivariable Cox proportional hazards model, we found IPF (hazard ratio [HR] 3.51, 95% confidence interval [CI] 1.33-8.21, P = .01) and alemtuzumab induction therapy (HR 2.73, 95% CI 1.10-6.74, P = .03) as risk factors for PTLD, compared to EBV mismatch (HR: 34.43, 95% CI 15.57-76.09, P < .0001). Early PTLD (first year) was associated with alemtuzumab use (P = .04), whereas IPF was a predictor for late PTLD (after first year) (P = .002), after controlling for age and sex. Kaplan-Meier analysis revealed a shorter time to death from PTLD in IPF LTRs compared to other patients (P = .04). The use of alemtuzumab in EBV mismatch was found to particularly increase PTLD risk. Together, our findings identify IPF LTRs as a susceptible population for PTLD. Further studies are required to understand the mechanisms driving PTLD in IPF LTRs and develop strategies to mitigate risk.

Aerosolization of Second-generation Triazoles: In Vitro Evaluation and Application in Therapy of Invasive Airway Aspergillosis.

BACKGROUND: A lung transplant patient with invasive aspergillosis (IA) manifested symptoms of voriconazole-induced transaminitis with systemic voriconazole and progression of IA after switching to oral posaconazole. With limited options for standard triazole therapy, aerosolized delivery with one of the second-generation triazoles was considered. METHODS: Feasibility for aerosolized delivery was evaluated using cascade impactor and analysis of physicochemical characteristics of voriconazole (10 mg/mL) and posaconazole (6, 12 mg/mL) solutions. RESULTS: Both triazoles showed favorable characteristics for aerosol delivery with mass median aerodynamic diameter, geometric standard deviation, respirable fraction (<5.4 µm) of 2.8 µm, 2.0, 86%; 3.4 µm, 2.4, 78%; and 3.0 µm, 2.3, 79% for voriconazole and 6, 12 mg/mL of posaconazole, respectively. Aspergillus fumigatus isolate from the patient was more susceptible to voriconazole, and hence aerosolized voriconazole was introduced around the third month posttransplant at 40 mg TID for 1 week, 40 mg BID for 1 week, followed by 40 mg daily thereafter, along with IV caspofungin (50 mg/d) and liposomal amphotericin B (300 mg/d). The aerosol regimen was well tolerated by the patient with undetectable trough plasma levels of voriconazole. Bronchoscopy at the fourth month revealed improvement in anastomotic plaques with reduction in bronchoalveolar lavage galactomannan values (7.48-2.15 ng/mL). This consolidated aerosolized and intravenous regimen was maintained until 2.97 years posttransplant. CONCLUSIONS: The intravenous solutions of both second-generation triazoles showed characteristics that were suitable for aerosol delivery. Our report further adds to the therapeutic experience with the use of aerosolized voriconazole for IA in a lung transplant patient.

Impaired Cytomegalovirus Immunity in Idiopathic Pulmonary Fibrosis Lung Transplant Recipients with Short Telomeres.

RATIONALE: Cytomegalovirus (CMV)-related morbidities remain one of the most common complications after lung transplantation and have been linked to allograft dysfunction, but the factors that predict high risk for CMV complications and effective immunity are incompletely understood. OBJECTIVES: To determine if short telomeres in idiopathic pulmonary fibrosis (IPF) lung transplant recipients (LTRs) predict the risk for CMV-specific T-cell immunity and viral control. METHODS: We studied IPF-LTRs (n = 42) and age-matched non-IPF-LTRs (n = 42) and assessed CMV outcomes. We measured lymphocyte telomere length and DNA sequencing, and assessed CMV-specific T-cell immunity in LTRs at high risk for CMV events, using flow cytometry and fluorescence in situ hybridization. MEASUREMENTS AND MAIN RESULTS: We identified a high prevalence of relapsing CMV viremia in IPF-LTRs compared with non-IPF-LTRs (69% vs. 31%; odds ratio, 4.98; 95% confidence interval, 1.95-12.50; P < 0.001). Within this subset, IPF-LTRs who had short telomeres had the highest risk of CMV complications (P < 0.01) including relapsing-viremia episodes, end-organ disease, and CMV resistance to therapy, as well as shorter time to viremia versus age-matched non-IPF control subjects (P < 0.001). The short telomere defect in IPF-LTRs was associated with significantly impaired CMV-specific proliferative responses, T-cell effector functions, and induction of the major type-1 transcription factor T-bet (T-box 21;TBX21). CONCLUSIONS: Because the short telomere defect has been linked to the pathogenesis of IPF in some cases, our data indicate that impaired CMV immunity may be a systemic manifestation of telomere-mediated disease in these patients. Identifying this high-risk subset of LTRs has implications for risk assessment, management, and potential strategies for averting post-transplant CMV morbidities.

Systematic review and meta-analysis of post-transplant lymphoproliferative disorder in lung transplant recipients.

A systematic review of papers in English on post-transplant lymphoproliferative disorder (PTLD) in lung transplant recipients (LTR) using MEDLINE, EMBASE, SCOPUS, and Cochrane databases was performed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations were strictly adhered to. Pooled odds ratios (pOR) were calculated from a random-effects model, and heterogeneity among studies was quantitated using I2 values. Fourteen studies published from 2005 to 2015 were included in the meta-analysis. One hundred and sixty-four lung transplant recipients were included. LTRs who received single vs bilateral were associated with a 7.67-fold risk of death after PTLD (6 studies with 64 LTRs; pOR 7.67 95% CI 1.98-29.70; P = .003). pOR of death for early onset PTLD (<1 year post-LT) vs late onset (>1 year post-LT) was not different (3 studies with 72 LTRS; pOR 0.62, 95% CI 0.20-1.86, P = .39). Standardized mean difference (SMD) in time from transplant to PTLD onset between LTRs who died vs alive was not different (9 studies with 109 LTRs; SMD 0.03, 95% CI -0.48-0.53, P = .92). Survival in polymorphic vs monomorphic PTLD and extranodal vs nodal disease was similar (4 studies with 31 LTRs; pOR 0.44, 95% CI 0.08-2.51; P = .36. 6 studies with 81 LTRs; pOR 1.05 95% CI 0.31-3.52, P = .94). This meta-analysis demonstrates that single LTRs are at a higher risk of death vs bilateral LTRs after the development of PTLD.

Comparative Effectiveness and Safety Analysis of Dual Antiplatelet Therapies Within an Integrated Delivery System.

BACKGROUND: Dual antiplatelet therapy is a mainstay of care for percutaneous coronary intervention (PCI) patients; however, uncertainty exists in real-world practice about comparative effectiveness and safety outcomes. OBJECTIVE: To evaluate outcomes of different oral P2Y12 inhibitors in PCI patients. METHODS: We retrospectively studied patients treated between July 1, 2010, and December 31, 2013. Patients received clopidogrel, prasugrel, ticagrelor, or more than 1 antiplatelet (switch) during PCI. Outcomes were evaluated for major adverse cardiovascular events (MACE) and bleeding at 1 year. Propensity score matching with Cox proportional hazards analysis was used to determine predictors of MACE and bleeding. RESULTS: A total of 8127 patients were included: clopidogrel (n = 6872), prasugrel (n = 605), ticagrelor (n = 181), and switch (n = 469). Treatment with prasugrel was associated with the lowest risk of MACE using multivariate regression (odds ratio [OR] = 0.57; 95% CI = 0.36-0.92; P = 0.02). In the propensity score-matched analysis, only the prasugrel group was associated with a lower risk of MACE compared with the clopidogrel group. Clopidogrel was associated with the lowest risk of major bleeding using multivariate regression (OR = 0.64; 95% CI = 0.42-0.98; P = 0.042). Both ticagrelor (hazard ratio [HR] = 2.00; 95% CI = 1.11-3.59) and the switch groups (HR = 1.65; 95% CI = 1.09-2.50) were associated with a greater risk of major bleeding compared with clopidogrel. However, no differences were found in the propensity score-matched analysis. CONCLUSIONS: Dual antiplatelet therapies differed in both MACE and bleeds in a real-world setting of PCI. Prasugrel was associated with fewer MACE, whereas clopidogrel had fewer major bleeding events.

Triple Antithrombotic Therapy With Aspirin, P2Y12 Inhibitor, and Warfarin After Percutaneous Coronary Intervention: An Evaluation of Prasugrel or Ticagrelor Versus Clopidogrel.

BACKGROUND: Triple antithrombotic therapy is used in patients who require systemic anticoagulation and undergo percutaneous coronary intervention (PCI) requiring dual antiplatelet therapy. Bleeding with this combination is significant; however, few studies have described outcomes with the use of newer oral P2Y12 inhibitors in this setting. OBJECTIVES: We aimed to compare outcomes among patients prescribed triple therapy with prasugrel or ticagrelor compared to triple therapy with clopidogrel in patients who underwent PCI and required warfarin. METHODS: We retrospectively evaluated 168 patients who received either prasugrel (n = 32) or ticagrelor (n = 10) and were matched (1:3) to those who received clopidogrel (n = 126) at the time of discharge from the index PCI visit. Matching was performed based on age ±10 years, sex, and indication for PCI. The primary outcome was the incidence of any bleeding during the 12-month follow-up. We also evaluated major adverse cardiovascular and cerebrovascular events (MACCEs). RESULTS: Patient baseline characteristics were similar between groups. There was a significant excess of bleeding in patients who received prasugrel or ticagrelor compared to clopidogrel as part of triple therapy (28.6% vs 12.7%; odds ratio, 3.3; 95% confidence interval, 1.38-8.34). No differences were seen between groups in MACCEs. CONCLUSIONS: The use of prasugrel or ticagrelor as part of triple antithrombotic therapy among patients who underwent PCI and received warfarin was associated with significantly more bleeding compared to patients who received clopidogrel. Therefore, higher potency P2Y12 inhibitors should be used cautiously in these patients.

Janus kinase inhibition for immunosuppression in solid organ transplantation: Is there a role in complex immunologic challenges?

Inhibition of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway for immunosuppression in solid organ transplantation is appealing due to its specificity for immune cell function, particularly for JAK3. This is due to its unique association with only the common gamma chain (γc). The γc is an appealing immunosuppression target in transplantation because of the critically important lymphokines that act at it, including IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21. Tofacitinib was initially purported to selectively inhibit solely JAK3, but subsequent analyses have also demonstrated its activity at the other members of the JAK family. Clinical outcomes have validated tofacitinib's pan-JAK activity in kidney transplantation after demonstrating an increased risk of infection and malignancy as compared to CNI-based regimens. After these trials, tofacitinib investigation for use in transplantation has effectively ceased. However, a post-hoc analysis has shed new light on the monitoring of tofacitinib exposure in order to predict infection and oncologic events. With new methods to monitor tofacitinib exposure, clinicians may be able to effectively reduce toxicities while providing a high level of immunosuppression. The purpose of this review to identify when, and for whom, JAK inhibitors may provide benefit in solid organ transplantation.