Allogeneic transplantation is encumbered by the toxicities of chronic immunosuppression, driving innovations for lifelong graft acceptance without ongoing therapy. Transplantation tolerance, a recipient-centric strategy, utilizes central deletional processes through mixed hematopoietic chimerism and thymic repertoire sculpting, complemented by peripheral mechanisms such as T cell anergy, exhaustion, apoptotic deletion, and regulatory T cell dominance. Adjunctive costimulatory blockade enhances the latter pathways, yet tolerance remains precarious, susceptible to destabilization by infections or inflammatory perturbations via heterologous immunity. Conversely, immune evasion adopts a product-centric approach, engineering grafts to intrinsically circumvent adaptive allorejection, innate cytotoxicity, and autoimmune recognition and responses. These mechanistic contrasts-dynamic recipient modulation versus robust graft stealth-underscore immune evasion's transformative promise and resilience, with empirical validation for cell and organoid transplantation. This review focusses on islet cell replacement therapy, wherein cadaveric allogeneic islet allografts have been clinically available for over four decades, complemented by recent advancements in stem cell-derived islet products.

The need to suppress a patient's immune system after the transplantation of allogeneic cells is associated with wide-ranging side effects. We report the outcomes of transplantation of genetically modified allogeneic donor islet cells into a man with long-standing type 1 diabetes. We used clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 12b (Cas12b) editing and lentiviral transduction to genetically edit the cells to avoid rejection; the cells were then transplanted into the participant's forearm muscle. He did not receive any immunosuppressive drugs and, at 12 weeks after transplantation, showed no immune response against the gene-edited cells. C-peptide measurements showed stable and glucose-responsive insulin secretion. A total of four adverse events occurred, none of which were serious or related to the study drug. (Funded by the Leona M. and Harry B. Helmsley Charitable Trust; EudraCT number, 2023-507988-19-00; ClinicalTrials.gov number, NCT06239636.).

Hypoimmune (HIP) MHC class I- and II-deficient and CD47-overexpressing CD19 CAR T cells were generated and tested in an allogeneic NZB/W mouse model of spontaneous systemic lupus erythematosus with established disease. HIP CAR T cells showed persistent engraftment, achieved lasting deep tissue B cell depletion, diminished antibody levels and systemic pro-inflammatory cytokine levels, mitigated proteinuria and glucosuria, alleviated structural kidney injury, and improved survival after 21 weeks. HIP CAR T cells did not induce any immune activation in this fully allogeneic model and thus completely escaped allorejection. In contrast, MHC-replete, non-HIP-edited wild-type (WT) CD19 CAR T cells induced a strong adaptive immune response and vanished quickly without inducing meaningful B cell depletion and without improving disease markers or survival. Conditioning of NZB/W mice with irradiation did not enhance the HIP CAR T cell efficacy and might hint at their potency for autoimmune patients without prior lymphodepletion.

Allogeneic, immune-evasive hypoimmune (HIP) cell therapeutics that are HLA-depleted and overexpress CD47 create the opportunity to treat immunocompetent patients with cancer, degenerative, or autoimmune diseases. However, HIP cell therapy has not yet been established for xenotransplantation. Here we engineer, for human-to-non-human primate studies, human HIP* endothelial cells (EC) that are HLA-depleted and express macaque CD47 to allow compatibility with the macaque SIRPα immune checkpoint. Although no T cell, NK cell, or macrophage responses and no antibody-dependent cytotoxicity is observed in cynomolgus recipients, we reveal that macaque polymorphonuclear cells (PMN) show strong xenogeneic cytotoxicity against HIP* ECs. Inhibition of PMN killing using a multi-drug regimen leads to improved xenogeneic human HIP* EC survival in cynomolgus monkeys. Similarly, human PMNs show xenoreactivity against pig ECs, which has implications for clinical xenotransplantation. Accordingly, our engineered pig HIP* ECs that are SLA-depleted, overexpress human CD47, and additionally overexpress the PMN-inhibitory ligands CD99 and CD200, are protected against all human adaptive and innate cytotoxicity, including PMNs. In summary, specific targeting of PMN-mediated killing of the transplanted cells might improve outcomes for clinical pig-to-human xenotransplantation.

Off-the-shelf CAR T cells need to reliably escape allogeneic immune responses to become universal medicines. The primary T cell product SC291 was engineered with a CD19 CAR, T cell receptor alpha constant (TRAC) knockout, and the hypoimmune (HIP) edits of HLA depletion and CD47 overexpression. Here, we report exploratory immune analyses from the ARDENT (NCT05878184) and GLEAM (NCT06294236) trials with HIP-edited CD19 CAR T cells. Although there was an alloimmune response against HLA-replete subpopulations of SC291, we observed no de novo immune response against fully edited HIP CAR T cells in all patients, irrespective of the dose or the patient's disease. The lack of antibodies against the HLA-replete CAR T cells was identified as a marker for deep tissue CD19 cell depletion, and all patients without such antibodies for 60 days showed concomitant B cell depletion in peripheral blood. The immune data presented support the reliability of the HIP concept to evade allorejection.

The new era of cell therapeutics has started with autologous products to avoid immune rejection. However, therapeutics derived from allogeneic cells could be scaled and made available for a much larger patient population if immune rejection could reliably be overcome. In this review, we outline gene engineering concepts aimed at generating immune-evasive cells. First, we summarize the current state of allogeneic immune cell therapies, and second, we compile the still limited data for allogeneic cell replacement therapies. We emphasize the advances in this fast-developing field and provide an optimistic outlook for future allogeneic cell therapies.

Allogeneic transplantation of pancreatic islets for patients with difficult-to-control diabetes mellitus is severely hampered by the requirement for continuous immunosuppression and its associated morbidity. We report that allogeneic transplantation of genetically engineered (B2M-/-, CIITA-/-, CD47+), primary, hypoimmune, pseudo-islets (p-islets) results in their engraftment into a fully immunocompetent, diabetic non-human primate wherein they provide stable endocrine function and enable insulin independence without inducing any detectable immune response in the absence of immunosuppression. Hypoimmune primary p-islets may provide a curative cell therapy for type 1 diabetes mellitus.

Genetic engineering of allogeneic cell therapeutics that fully prevents rejection by a recipient’s immune system would abolish the requirement for immunosuppressive drugs or encapsulation and support large-scale manufacturing of off-the-shelf cell products. Previously, we generated mouse and human hypoimmune pluripotent (HIP) stem cells by depleting HLA class I and II molecules and overexpressing CD47 ( B2M −/− CIITA −/− CD47 + ). To determine whether this strategy is successful in non-human primates, we engineered rhesus macaque HIP cells and transplanted them intramuscularly into four allogeneic rhesus macaques. The HIP cells survived unrestricted for 16 weeks in fully immunocompetent allogeneic recipients and differentiated into several lineages, whereas allogeneic wild-type cells were vigorously rejected. We also differentiated human HIP cells into endocrinologically active pancreatic islet cells and showed that they survived in immunocompetent, allogeneic diabetic humanized mice for 4 weeks and ameliorated diabetes. HIP-edited primary rhesus macaque islets survived for 40 weeks in an allogeneic rhesus macaque recipient without immunosuppression, whereas unedited islets were quickly rejected.

Hypoimmune (HIP) allogeneic cell therapeutics hold the promise to allow off-the-shelf treatments for a broad patient population. Our HIP approach includes the depletion of major histocompatibility complex (MHC) class I and II molecules and the overexpression of Cd47. Here, we report the engineering of HIP mice that stably exhibit the HIP phenotype in all cell types. Parabiosis experiments were designed to broadly assess immune evasiveness of all HIP blood cells in fully allogeneic BALB/c mice. HIP blood cells did not induce any immune response and achieved stable engraftment in BALB/c mice. Parabiosis experiments with irradiated HIP mice served as a model for full-body transplantation. There was no measurable cellular or antibody response in immunocompetent, allogeneic BALB/c parabionts. Transplantation of HIP islets into diabetic, allogeneic BALB/c mice reliably treated diabetes in all animals. Together, these data suggest that all allogeneic tissues can be HIP engineered and HIP cell therapy may be envisioned for many more indications.

Purpose: Despite the advent of direct acting antivirals (DAA), the Hepatitis C viremic (HCV+) donors remain an untapped pool. Furthermore, published studies to date have been limited to successful outcomes in low risk profile candidates. Here, we report a case series of lung transplantation (LTx) from HCV+ donors into a cohort that includes: 1) Critically ill patients with high allocation score (LAS/CAS) on ECMO and mechanical ventilation, 2) Highly sensitized patients, and 3) Patients at risk for malabsorption.

Background:The use of hydroxocobalamin following lung transplantation has not been previously reported. We present a series of 3 cases where hydroxocobalamin was used to treat postoperative vasoplegia. Methods:We conducted a single-center, retrospective review of lung transplantation recipients from January 2016 to December 2020. We used cumulative vasopressor index to standardize vasopressor dose administered and mean arterial pressure at 2- and 24-hour time-points following hydroxocobalamin administration to assess treatment effectiveness. Results:We identified 3 male patients aged 49 to 62, with lung allocation scores between 89.9 and 90.6, requiring extracorporeal membrane oxygenation support (pre- and post-transplant for 5, 5, 9 and 8, 2, 2 days, respectively). Each patient received hydroxocobalamin 5,000 mg infused over 15 minutes, with patient #3 receiving an additional 6 doses over the subsequent 4 days. At the 2-hour time-point, mean arterial pressure increased in all patients (+11%, +17%, and +13%, respectively), although cumulative vasopressor indexes were inconsistent. At 24 hours, patients #1 and #2 demonstrated a marked increase in mean arterial pressure (36% and 23%, respectively) and a decrease in cumulative vasopressor index, while patient #3 displayed stable with slight reduction in cumulative vasopressor index and mean arterial pressure values. No allergic reactions were observed. Patient #3 developed methemoglobinemia and a medication-related false increase in triglycerides. All 3 patients were discharged home. Conclusions:Hydroxocobalamin may be a valuable adjunct in managing refractory vasoplegia following lung transplantation.

Treatment of type 1 diabetes mellitus (T1DM) via allogeneic donor transplant has limited success due to morbidities from immunosuppression (IS) and a gradual loss of engrafted pancreatic islet function. We report that allogeneic transplantation of engineered, primary, hypoimmune, pseudo-islets (HIP p-islets) engraft into a fully immunocompetent, diabetic non-human primate (NHP), provide stable endocrine function, and enable insulin independence without inducing any detectable immune response in the absence of IS. NHP cadaveric islet cells were engineered to disrupt function of MHC class I and II and overexpress CD47 thus rendering them hypoimmune (HIP). Diabetes was induced in the NHP with streptozotocin and daily insulin injections started to re-establish glucose control. After 78 days, NHP underwent transplantation of HIP p-islets by intramuscular injection resulting in insulin independence. As early as one week after the transplantation, the NHP’s serum c-peptide level had normalized and remained stable throughout the follow-up period of 6 months. The NHP showed tightly controlled blood glucose levels for 6 months, was completely insulin-independent, and continuously healthy. Up to 6 months after HIP p-islet transplantation, PBMCs and serum were obtained for immune analyses. HIP PI showed no T cell recognition, no graft-specific antibodies, and were protected from NK cell and macrophage killing. To prove that the monkey’s insulin-independence was fully dependent on the HIP p-islets graft and there was no regeneration of his endogenous islet cell population, we triggered the destruction of the HIP p-islet transplant using a CD47-targeting strategy resulting in loss of glycemic control and return to exogenous insulin dependence. These data demonstrate evidence for immune evasion of HIP p-islets, graft mediated insulin-independence of the diabetic NHP, and a potential safety strategy. Disclosure X. Hu: Employee; Sana Biotechnology. Stock/Shareholder; Sana Biotechnology. K. White: None. C. Young: Employee; Sana biotechnology. Stock/Shareholder; Sana biotechnology. A.G. Olroyd: Employee; Sana Biotechnology. Stock/Shareholder; Sana Biotechnology. P. Kievit: Consultant; Alnylam Pharmaceuticals, Inc., Embark Bio. Research Support; Sana Biotechnology, Novo Nordisk A/S. A. Connolly: None. T. Deuse: Stock/Shareholder; Sana Biotechnology, Shinobi Therapeutics. S. Schrepfer: Stock/Shareholder; Sana Biotechnology. Employee; Sana Biotechnology.

ObjectiveThe objective of this study is to evaluate survival for combined heart-lung transplant (HLTx) recipients across four decades at a single institution. We aim to summarize our contemporary practice based upon more than 271 HLTx over 40 years.MethodsData were collected from a departmental database and the United Network for Organ Sharing (UNOS). Recipients <18y, those undergoing redo HLTx , or triple-organ system transplantation were excluded, leaving 271 patients for analysis. The Pioneering Era was defined by date of transplant between 1981-2000 (N=155), and the Modern Era between 2001-2022 (N=116). Survival analysis was performed using cardinality matching of populations based on donor and recipient age, donor and recipient sex, ischemic time, and sex-matching.ResultsBetween 1981-2022, 271 HLTx were performed at a single institution. Recipients in the Modern Era were older (42 vs 34y, P<0.001) and had shorter waitlist times (78 vs 234d, P<0.001). Allografts from female donors were more common in the Modern Era (59% vs 39%, P=0.002). In the matched survival analysis, 30-day survival (97% vs 84%, P=0.005), 1-year survival (89% vs 77%, P=0.041), and 10-year survival (53% vs 26%, P=0.012) significantly improved in the Modern Era relative to the Pioneering Era, respectively.ConclusionsLong-term survival in HLTx is achievable with institutional experience and may continue to improve in the coming decades. Advances in mechanical circulatory support, improved maintenance immunosuppression, and early recognition and management of acute complications such as primary graft dysfunction and acute rejection have dramatically improved the prognosis for HLTx recipients in our contemporary institutional experience.

OBJECTIVE:The objective of this study is to evaluate survival for combined heart-lung transplant (HLTx) recipients across 4 decades at a single institution. We aim to summarize our contemporary practice based on more than 271 HLTx procedures over 40 years. METHODS:Data were collected from a departmental database and the United Network for Organ Sharing. Recipients younger than age 18 years, those undergoing redo HLTx, or triple-organ system transplantation were excluded, leaving 271 patients for analysis. The pioneering era was defined by date of transplant between 1981 and 2000 (n = 155), and the modern era between 2001 and 2022 (n = 116). Survival analysis was performed using cardinality matching of populations based on donor and recipient age, donor and recipient sex, ischemic time, and sex matching. RESULTS:Between 1981 and 2022, 271 HLTx were performed at a single institution. Recipients in the modern era were older (age 42 vs 34 y; P < .001) and had shorter waitlist times (78 vs 234 days; P < .001). Allografts from female donors were more common in the modern era (59% vs 39%; P = .002). In the matched survival analysis, 30-day survival (97% vs 84%; P = .005), 1-year survival (89% vs 77%; P = .041), and 10-year survival (53% vs 26%; P = .012) significantly improved in the modern era relative to the pioneering era, respectively. CONCLUSIONS:Long-term survival in HLTx is achievable with institutional experience and may continue to improve in the coming decades. Advances in mechanical circulatory support, improved maintenance immunosuppression, and early recognition and management of acute complications such as primary graft dysfunction and acute rejection have dramatically improved the prognosis for recipients of HLTx in our contemporary institutional experience.

CYSTIC FIBROSIS is a genetic disorder that affects nearly 40,000 Americans. Approximately 11,000 deaths per year are attributed to cystic fibrosis in the United States. Recent improvements in management have had a significant impact on the cystic fibrosis population—between 1999 and 2020, cystic fibrosis-related mortality decreased from 1.9 to 1.04 per million Americans. Life expectancy has increased from 24 to 37 years. Advances include nationwide newborn screening, infection prevention, targeted nutritional support, enhanced pancreatic function, improved mucociliary clearance, and the introduction of highly effective cystic fibrosis transmembrane conductance regulator protein modulators into clinical practice. The establishment of specialized cystic fibrosis care centers has proven to be helpful in optimizing outcomes. In this issue of the Journal of Cardiothoracic and Vascular Anesthesia, von Dossow and coworkers1von Dossow V, Hulde N, Starke H, et al. How would we treat our own cystic fibrosis with lung transplantation? J Cardiothorac Vasc Anesth. 10.1053/j.jvca.2023.10.036. Accessed December 12, 2023.Google Scholar presented the case of a 48-year-old male patient with cystic fibrosis and pulmonary artery hypertension who underwent double-lung transplantation. The clinical course was uneventful and well-managed. The authors addressed the considerations in the care of today's cystic fibrosis population when it comes to transplantation. Although medical treatment has been successful in improving the quality of life and life expectancy of cystic fibrosis patients,2Singh H Jani C Marshall DC et al.Cystic fibrosis-related mortality in the United States from 1999 to 2020: An observational analysis of time trends and disparities.Sci Rep. 2023; 13: 15030Crossref PubMed Scopus (1) Google Scholar lung transplantation remains the only option when all medical therapies have been exhausted.3Kapnadak SG Dimango E Hadjiliadis D et al.Cystic Fibrosis Foundation consensus guidelines for the care of individuals with advanced cystic fibrosis lung disease.J Cyst Fibros. 2020; 19: 344-354Abstract Full Text Full Text PDF PubMed Scopus (98) Google Scholar In the new era of cystic fibrosis therapy, patients presenting for lung transplantation are significantly older.2Singh H Jani C Marshall DC et al.Cystic fibrosis-related mortality in the United States from 1999 to 2020: An observational analysis of time trends and disparities.Sci Rep. 2023; 13: 15030Crossref PubMed Scopus (1) Google Scholar This has significant implications, as the incidence of comorbidities, chronic infections, especially with multidrug-resistant infectious pathogens, pancreatic insufficiency with gastrointestinal complications, malnutrition, liver involvement, and other chronic manifestations, are increasing.4Mallea J Bolan C Cortese C et al.Cystic fibrosis-associated liver disease in lung transplant recipients.Liver Transpl. 2019; 25: 1265-1275Crossref PubMed Scopus (11) Google Scholar The patient with cystic fibrosis must be evaluated carefully by a multidisciplinary team before being considered for lung transplantation. Given the success of newer medical treatments, it must be determined that all nontransplant treatment options have been exhausted. A lung transplant program should include experts in cystic fibrosis therapy.5Ramos KJ Smith PJ McKone EF et al.Lung transplant referral for individuals with cystic fibrosis: Cystic Fibrosis Foundation consensus guidelines.J Cyst Fibros. 2019; 18: 321-333Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar In the case presented in the article by von Dossow,1von Dossow V, Hulde N, Starke H, et al. How would we treat our own cystic fibrosis with lung transplantation? J Cardiothorac Vasc Anesth. 10.1053/j.jvca.2023.10.036. Accessed December 12, 2023.Google Scholar dependence on high fractions of inspired oxygen was a clear sign of irreversible lung destruction and the need for transplantation. However, many patients with cystic fibrosis are not oxygen-dependent when they become candidates for lung transplantation. They may have gone through increasingly frequent decompensations with intermittent high oxygen requirements. The Cystic Fibrosis Foundation defines criteria for referral and listing for lung transplantation that are largely related to the dynamics of the disease, such as a rapid decline in forced expiratory volume in one second over 12 months, more than 2 exacerbations per year, severe hemoptysis, development of pneumothorax, and body mass index <18 kg/m2 despite aggressive attempts to gain weight.5Ramos KJ Smith PJ McKone EF et al.Lung transplant referral for individuals with cystic fibrosis: Cystic Fibrosis Foundation consensus guidelines.J Cyst Fibros. 2019; 18: 321-333Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar A careful evaluation of the infectious colonization of the recipient should be performed to allow planning of posttransplant management. Due to the aggressive and prolonged antibiotic treatment of patients with cystic fibrosis, almost all transplant candidates today have complex and multiresistant flora. This should not exclude them from transplantation, but requires the involvement of an experienced and dedicated infectious disease service that will continue to follow the patient after lung transplantation. Because sinus colonization is common and may require treatment, it is necessary to consult with and obtain the approval of an otolaryngologist before active listing. In particular, fungal infections with Aspergillus, which have an incidence up to 4 times higher in patients with cystic fibrosis than in other patients with end-stage lung disease, need to be addressed carefully, and plans need to be made for post-transplant care. The intraoperative management of cystic fibrosis patients is challenging. Many of the candidates have already undergone thoracic surgery, whether for abscess drainage, chest tube drainage of pneumothorax, partial lung resection for infectious complications, or open lung biopsy. Some patients may have extensive adhesions, which may increase the risk of severe bleeding during lung removal. Thus, blood products should be available immediately. Hemostatic agents and local hemostatic devices, such as argon beams, powders, adhesives, or other products, should be present in the operating room. Bleeding from adhesions in the chest must be treated effectively before the new lungs are implanted. The use of mechanical circulatory support (MCS) devices during lung transplantation remains controversial. The authors prefer the use of venoarterial (VA) extracorporeal membrane oxygenation (ECMO) in double-lung transplantation. In other cases, MCS should be avoided, if possible. Although the authors only would use conventional cardiopulmonary bypass—as in cardiac surgery—in patients in whom severe bleeding is expected, the authors are reluctant to use this strategy in patients with cystic fibrosis during lung transplantation. Due to the high infection burden, the authors are concerned about contamination of the salvaged autologous blood, which could lead to septic shock. Even if this means that the patient receives more blood transfusions than usual, the authors try to avoid retransfusion of autologous blood. In all cases, a cell-saver device is used. However, retransfusion of this blood is avoided. Instead, the salvaged blood is kept in reserve for emergencies and discarded at the end of the case if not transfused. The intraoperative strategy requires solid case planning and clear, continuous communication among the anesthesiologist, the perfusionist, and the surgeon to safely manage complex situations. Left ventricular diastolic dysfunction is recognized increasingly as a strong predictor of adverse cardiovascular events and mortality.6Ladeiras-Lopes R Araújo M Sampaio F et al.The impact of diastolic dysfunction as a predictor of cardiovascular events: A systematic review and meta-analysis.Rev Port Cardiol (Engl Ed). 2019; 38: 789-804Crossref PubMed Scopus (20) Google Scholar Cardiovascular surgery patients with grade III diastolic dysfunction, corresponding to restrictive filling with elevated filling pressure and noncompliant left ventricle, have a 21% odds ratio of postoperative mortality compared to normal diastolic patients.7Kaw R Hernandez AV Pasupuleti V et al.Effect of diastolic dysfunction on postoperative outcomes after cardiovascular surgery: A systematic review and meta-analysis.J Thorac Cardiovasc Surg. 2016; 152: 1142-1153Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar In lung transplantation, there are compelling data that diastolic dysfunction contributes significantly to early postoperative morbidity and worse survival in patients with pulmonary artery hypertension.8Avriel A Klement AH Johnson SR et al.Impact of left ventricular diastolic dysfunction on lung transplantation outcome in patients with pulmonary arterial hypertension.Am J Transplant. 2017; 17: 2705-2711Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar In the case presented by von Dossow,1von Dossow V, Hulde N, Starke H, et al. How would we treat our own cystic fibrosis with lung transplantation? J Cardiothorac Vasc Anesth. 10.1053/j.jvca.2023.10.036. Accessed December 12, 2023.Google Scholar the decision to use VA ECMO was based on the moderate primary graft failure and, in particular, on the severe left ventricular diastolic dysfunction, which was more evident after donor organ implantation. However, it is clear that VA ECMO is far from being the optimal temporary MCS for the left ventricle in case of failure. Increasing ECMO flow leads to a continuous rightward shift of the left ventricular pressure-volume loop, increasing left ventricular afterload, and potentially promoting left ventricular congestion. Although the interaction between systolic left ventricular function and peripheral VA ECMO flow-related afterload increase has been extensively studied, the dynamics of ECMO support and diastolic left ventricular dysfunction and left ventricular congestion have, to the authors' knowledge, not yet been investigated adequately.9Ng PY Ma TSK Ip A et al.Sensitivity of ventricular systolic function to afterload during veno-arterial extracorporeal membrane oxygenation.ESC Heart Fail. 2022; 9: 3241-3253Crossref PubMed Scopus (3) Google Scholar,10Guglin M Zucker MJ Bazan VM et al.Venoarterial ECMO for adults: JACC scientific expert panel.J Am Coll Cardiol. 2019; 73: 698-716Crossref PubMed Scopus (297) Google Scholar Given this, strategies for timely ECMO weaning should be considered early in the process of implanting ECMO. Currently, even if the data are limited to observational studies, the use of levosimendan has shown promise regarding successful weaning and increased survival in patients on VA ECMO support.11Bertini P Paternoster G Landoni G et al.Beneficial effects of levosimendan to wean patients from VA-ECMO: A systematic review and meta-analysis.Minerva Cardiol Angiol. 2023; 71: 564-574Crossref PubMed Scopus (3) Google Scholar However, most of these patients presented with acute myocardial infarction or postcardiotomy left ventricular failure. Considering the specific condition of severe diastolic dysfunction as the indication for ECMO support, specific aspects of this versatile agent can be highlighted. Depending on the preactivation of beta-adrenergic receptors, levosimendan is a potent calcium sensitizer and a highly selective phosphodiesterase III inhibitor. In addition, the opening of adenosine triphosphate-dependent potassium channels leads to vasodilation in selected organs.11Bertini P Paternoster G Landoni G et al.Beneficial effects of levosimendan to wean patients from VA-ECMO: A systematic review and meta-analysis.Minerva Cardiol Angiol. 2023; 71: 564-574Crossref PubMed Scopus (3) Google Scholar In an animal model of chronic pulmonary hypertension, levosimendan reduced pulmonary artery elastance and pulmonary vascular resistance.12Papp Z Agostoni P Alvarez J et al.Levosimendan efficacy and safety: 20 years of SIMDAX in clinical use.Card Fail Rev. 2020; 6: e19Crossref PubMed Scopus (38) Google Scholar Most importantly, in patients with heart failure, levosimendan improved both the systolic and diastolic functions of both ventricles.13Long YX Cui DY Kuang X et al.Effect of levosimendan on renal function in background of left ventricular dysfunction: A meta-analysis of randomized trials.Expert Opin Drug Saf. 2021; 20: 1411-1420Crossref PubMed Scopus (7) Google Scholar,14Maack C Eschenhagen T Hamdani N et al.Treatments targeting inotropy.Eur Heart J. 2019; 40: 3626-3644Crossref PubMed Scopus (116) Google Scholar In this context, levosimendan may be an interesting option for preconditioning VA ECMO weaning in lung transplant recipients with cystic fibrosis due to the combination of positive inotropic effects on the right ventricular function, reduction of pulmonary vascular resistance, and, in particular, its lusitropic effects on the left ventricle. Inhalation of the phosphodiesterase III inhibitor milrinone produces a rapid and potent reduction in pulmonary artery resistance that lasts for approximately 60 minutes.15Tavares-Silva M Alaa M Leite S et al.Dose-response head-to-head comparison of inodilators dobutamine, milrinone, and levosimendan in chronic experimental pulmonary hypertension.J Cardiovasc Pharmacol Ther. 2017; 22: 485-495Crossref PubMed Scopus (16) Google Scholar However, inhalation of milrinone at a standard dose of 5 mg rapidly leads to plasma concentrations of 50-to-100 µg/ml, which are known to have inotropic and potent lusitropic effects on left ventricular function.16Nguyen AQ Denault AY Théoret Y et al.Inhaled milrinone in cardiac surgical patients: pharmacokinetic and pharmacodynamic exploration.Sci Rep. 2023; 13: 3557Crossref PubMed Scopus (1) Google Scholar,17Yano M Kohno M Ohkusa T et al.Effect of milrinone on left ventricular relaxation and Ca(2+) uptake function of cardiac sarcoplasmic reticulum.Am J Physiol Heart Circ Physiol. 2000; 279: H1898-H1905Crossref PubMed Google Scholar Therefore, the authors believe that intermittent inhalation of milrinone may have been considered in conditions such as the presented case. The potential of both agents to facilitate timely VA ECMO weaning after lung transplantation could be expanded by further studies. Both agents, when inhaled, have been shown to attenuate lung injury, inflammatory response, and mortality in animal models of experimental acute lung injury.18Bueltmann M Kong X Mertens M et al.Inhaled milrinone attenuates experimental acute lung injury.Intensive Care Med. 2009; 35: 171-178Crossref PubMed Scopus (22) Google Scholar In this regard, the extent to which preemptive inhalation of milrinone or levosimendan after lung transplantation might affect early graft function and cardiac performance warrants further investigation. Postoperatively, patients with cystic fibrosis undergo the same monitoring as any other lung-transplant patient. Again, the infectious disease service must be involved consistently in advising on appropriate antibiotic and antifungal coverage. Immunosuppression follows standard protocol. However, the goal should be to minimize immunosuppression as much as safely possible. As patients with cystic fibrosis present for lung transplantation later in life, nutritional guidance and monitoring for gastrointestinal complications become more important.19Shah P Lowery E Chaparro C et al.Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients.J Heart Lung Transplant. 2021; 40: 539-556Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar Attempts to improve nutritional status before transplantation should be guided by experts. In any case, patients need good nutritional guidance in the postoperative period. In the intensive care unit, special attention must be paid to adequate bowel function. Given the high aspiration risk after lung transplantation, gastrointestinal management is critical to the success of lung transplantation. Some patients may require parenteral or postpyloric nutrition early after transplantation. In conclusion, lung transplantation remains the only option for patients with cystic fibrosis with very advanced disease. Patients regain a good quality of life, and their life expectancy is significantly extended. Careful planning in a specialized cystic fibrosis center, the involvement of a multidisciplinary team, good patient and caregiver education, and dedicated infection control make this complex procedure a lasting success. Matthias Loebe: Conceptualization, Validation, Writing – original draft, Writing – review & editing. Tobias Deuse: Writing – review & editing. Neeraj Sinha: Writing – review & editing. Andreas Koster: Conceptualization, Writing – original draft, Writing – review & editing. Gabor Erdoes: Conceptualization, Writing – original draft, Writing – review & editing. None.

Manufacturing autologous chimeric antigen receptor (CAR) T cell therapeutics is complex, and many patients experience treatment delays or cannot be treated at all. Although current allogeneic CAR products have the potential to overcome manufacturing bottlenecks, they are subject to immune rejection and failure to persist in the host, and thus do not provide the same level of efficacy as their autologous counterparts. Here, we aimed to develop universal allogeneic CAR T cells that evade the immune system and produce a durable response. We generated human hypoimmune (HIP) T cells with disrupted B2M, CIITA, and TRAC genes using CRISPR-Cas9 editing. In addition, CD47 and anti-CD19 CAR were expressed using lentiviral transduction. These allogeneic HIP CD19 CAR T cells were compared to allogeneic CD19 CAR T cells that only expressed the anti-CD19 CAR (allo CAR T). In vitro assays for cancer killing and exhaustion revealed no differences between allo CAR T and HIP CAR T cells, confirming that the HIP edits did not negatively affect T cell performance. Clearance of CD19+ tumors by HIP CAR T cells in immunodeficient NSG mice was comparable to that of allo CAR T cells. In fully immunocompetent humanized mice, HIP CAR T cells significantly outperformed allo CAR T cells, showed improved persistence and expansion, and provided lasting cancer clearance. Furthermore, CD47-targeting safety strategies reliably and specifically eliminated HIP CAR T cells. These findings suggest that universal allogeneic HIP CAR T cell-based therapeutics might overcome the limitations associated with poor persistence of allogeneic CAR T cells and exert durable anti-tumor responses.

Transplantation of allogeneic pancreatic donor islets has successfully been performed in selected patients with difficult-to-control insulin-dependent diabetes and impaired awareness of hypoglycemia (IAH). However, the required systemic immunosuppression associated with this procedure prevents this cell replacement therapy from more widespread adoption in larger patient populations. We report the editing of primary human islet cells to the hypoimmune HLA class I- and class II-negative and CD47-overexpressing phenotype and their reaggregation into human HIP pseudoislets (p-islets). Human HIP p-islets were shown to survive, engraft, and ameliorate diabetes in immunocompetent, allogeneic, diabetic humanized mice. HIP p-islet cells were further shown to avoid autoimmune killing in autologous, diabetic humanized autoimmune mice. The survival and endocrine function of HIP p-islet cells were not impaired by contamination of unedited or partially edited cells within the p-islets. HIP p-islet cells were eliminated quickly and reliably in this model using a CD47-targeting antibody, thus providing a safety strategy in case HIP cells exert toxicity in a future clinical setting. Transplantation of human HIP p-islets for which no immunosuppression is required has the potential to lead to wider adoption of this therapy and help more diabetes patients with IAH and history of severe hypoglycemic events to achieve insulin independence.

Allogeneic cell therapeutics for cancer therapy or regenerative medicine are susceptible to antibody-mediated killing, which diminishes their efficacy. Here we report a strategy to protect cells from antibody-mediated killing that relies on engineered overexpression of the IgG receptor CD64. We show that human and mouse iPSC-derived endothelial cells (iECs) overexpressing CD64 escape antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity from IgG antibodies in vitro and in ADCC-enabled mice. When CD64 expression was combined with hypoimmune genetic modifications known to protect against cellular immunity, B2M −/− CIITA −/− CD47/CD64-transgenic iECs were resistant to both IgG antibody-mediated and cellular immune killing in vitro and in humanized mice. Mechanistic studies demonstrated that CD64 or its intracellularly truncated analog CD64t effectively capture monomeric IgG and occupy their F c , and the IgG bind and occupy their target antigens. In three applications of the approach, human CD64t-engineered thyroid epithelial cells, pancreatic beta cells and CAR T cells withstood clinically relevant levels of graft-directed antibodies and fully evaded antibody-mediated killing.