Initial experience of dual maintenance immunosuppression with steroid withdrawal in vascular composite tissue allotransplantation

Immunosuppressive strategies in face and hand transplantation: a comprehensive systematic review of current therapy regimens and outcomes

Background

Recipients of Vascularized Composite Allotransplants require effective immunosuppressive therapy to prevent graft rejection. This systematic review summarizes the current body of literature on immunosuppressive regimens used in face and hand transplants while summarizing their outcome in terms of rejection, renal failure, and infections.

Methods

A systematic search of electronic databases was conducted to identify relevant studies from 1998 until July 1st, 2023. We included all studies that discussed immunosuppressive strategies in face and hand transplant recipients according to PRISMA.

Results

The standard triple maintenance therapy was mostly adjusted due to nephrotoxicity or high incidence of rejection. The most common alternative treatments utilized were sirolimus (25/91; 27.5%) or everolimus (9/91; 9.9%) following hand- and photophoresis (7/45; 15.6%), sirolimus (5/45; 11.1%) or belatacept (1/45; 2.2%) following face transplantation. Episodes of rejection were reported in 60 (65.9%) of hand- and 33 (73%) of face transplant patients respectively. Graft loss of 12 (13.2%) hand and 4 (8.9%) face transplants was reported. Clinical CMV infection was observed in 6 (6.6%) hand and 7 (15.5%) face transplant recipients.

Conclusions

Based on the herein presented data, facial grafts exhibited a heightened incidence of rejection episodes and CMV infections. Facial mucosa adds complexity to the immunological graft composition highlighting the need of individualized immunosuppressive regimens and further research.

Challenges and opportunities in vascularized composite allotransplantation of joints: a systematic literature review

Background

Joint allotransplantation (JA) within the field of vascularized composite allotransplantation (VCA) holds great potential for functional and non-prosthetic reconstruction of severely damaged joints. However, clinical use of JA remains limited due to the immune rejection associated with all forms of allotransplantation. In this study, we aim to provide a comprehensive overview of the current state of JA through a systematic review of clinical, animal, and immunological studies on this topic.

Methods

We conducted a systematic literature review in accordance with the PRISMA guidelines to identify relevant articles in PubMed, Cochrane Library, and Web of Science databases. The results were analyzed, and potential future prospects were discussed in detail.

Results

Our review included 14 articles describing relevant developments in JA. Currently, most JA-related research is being performed in small animal models, demonstrating graft survival and functional restoration with short-term immunosuppression. In human patients, only six knee allotransplantations have been performed to date, with all grafts ultimately failing and a maximum graft survival of 56 months.

Conclusion

Research on joint allotransplantation has been limited over the last 20 years due to the rarity of clinical applications, the complex nature of surgical procedures, and uncertain outcomes stemming from immune rejection. However, the key to overcoming these challenges lies in extending graft survival and minimizing immunosuppressive side effects. With the emergence of new immunosuppressive strategies, the feasibility and clinical potential of vascularized joint allotransplantation warrants further investigation.

A Systematic Review of the Reported Complications Related to Facial and Upper Extremity Vascularized Composite Allotransplantation

INTRODUCTION

Twenty three years after the first successful upper extremity transplantation, the role of vascularized composite allotransplantation (VCA) in the world of transplantation remains controversial. Face and upper extremity reconstruction via transplantation have become successful options for highly selected patients with severe tissue and functional deficit when conventional reconstructive options are no longer available. Despite clear benefit in these situations, VCA has a significant potential for complications that are more frequent when compared to visceral organ transplantation. This study intended to perform an updated systematic review on such complications.

MATERIALS AND METHODS

MEDLINE database via PubMed, Embase and Cochrane Library were searched. Face and upper extremity VCA performed between 1998 and 2021 were included in the study. Relevant media and press conferences reports were also included. Complications related to face and upper extremity VCA were recorded and reviewed including their clinical characteristics and complications.

RESULTS

One hundred fifteen patients underwent facial (43%) or upper extremity (57%) transplantation. Overall, the surgical complication rate was 23%. Acute and chronic rejection was identified in 89% and 11% of patients, respectively. Fifty eight percent of patients experienced opportunistic infection. Impaired glucose metabolism was the most common immunosuppression-related complication other than infection. Nineteen percent of patients ultimately experienced partial or complete allograft loss.

CONCLUSIONS

Complications related to VCA are a significant source of morbidity and potential mortality. Incidence of such complications is higher than previously reported and should be strongly emphasized in patient consent process. Strict patient selection criteria, complex preoperative evaluation, consideration of alternatives, and thorough disclosure to patients should be routinely performed prior to VCA indication.

Two Decades of Hand Transplantation: A Systematic Review of Outcomes

ABSTRACT

Hand transplantation for upper extremity amputation provides a unique treatment that restores form and function, which may not be achieved by traditional reconstruction and prosthetics. However, despite enhancing quality of life, hand transplantation remains controversial, because of immunological complications, transplant rejection, and medication effects. This systematic literature review sought to collect information on current experiences and outcomes of hand transplants to determine the efficacy and utility of hand transplants. The databases PubMed, Scopus, and Embase were analyzed with combinations of "hand" or "upper extremity" or "arm" and "transplant" or "allograft," with information collected on recipient characteristics, details of transplant, immunological outcomes, functional outcomes, and complications. Functional outcomes, as measured by Disabilities of Arm, Shoulder and Hand score, were compared between patient groups using Wilcoxon signed-rank test or 1-way analysis of variance test and post hoc Tukey test. Within the 108 articles that fulfilled inclusion and exclusion criteria, there were 96 patients with 148 hand transplants. There were 57 patients who experienced acute rejection and 5 patients with chronic rejection. Disabilities of the Arm, Shoulder and Hand scores significantly decreased after hand transplantation and were significantly lower for distal transplants compared with proximal transplants. There were 3 patients with concurrent face transplantation and 2 patients with simultaneous leg transplants. Sixteen patients experienced amputation of the hand transplant, and there were 5 deaths. This study found that hand transplantation provides significant restoration of function and form, especially for proximal transplants. Reduction in complications, such as rejection and amputation, can be achieved by decreasing medication cost and patient education.

Dual JAK2/Aurora kinase A inhibition prevents human skin graft rejection by allo-inactivation and ILC2-mediated tissue repair

Prevention of allograft rejection often requires lifelong immune suppression, risking broad impairment of host immunity. Nonselective inhibition of host T cell function increases recipient risk of opportunistic infections and secondary malignancies. Here we demonstrate that AJI-100, a dual inhibitor of JAK2 and Aurora kinase A, ameliorates skin graft rejection by human T cells and provides durable allo-inactivation. AJI-100 significantly reduces the frequency of skin-homing CLA⁺ donor T cells, limiting allograft invasion and tissue destruction by T effectors. AJI-100 also suppresses pathogenic Th1 and Th17 cells in the spleen yet spares beneficial regulatory T cells. We show dual JAK2/Aurora kinase A blockade enhances human type 2 innate lymphoid cell (ILC2) responses, which are capable of tissue repair. ILC2 differentiation mediated by GATA3 requires STAT5 phosphorylation (pSTAT5) but is opposed by STAT3. Further, we demonstrate that Aurora kinase A activation correlates with low pSTAT5 in ILC2s. Importantly, AJI-100 maintains pSTAT5 levels in ILC2s by blocking Aurora kinase A and reduces interference by STAT3. Therefore, combined JAK2/Aurora kinase A inhibition is an innovative strategy to merge immune suppression with tissue repair after transplantation.

Clinical and preclinical tolerance protocols for vascularized composite allograft transplantation

The field of vascularized composite allografts (VCAs) has undergone significant advancement in recent decades, and VCAs are increasingly common and accepted in the clinical setting, bringing hope of functional recovery to patients with debilitating injuries. A major obstacle facing the widespread application of VCAs is the side effect profile associated with the current immunosuppressive regimen, which can cause a wide array of complications such as infection, malignancy, and even death. Significant concerns remain regarding whether the treatment outweighs the risk. The potential solution to this dilemma would be achieving VCA tolerance, which would allow recipients to receive allografts without significant immunosuppression and its sequelae. Promising tolerance protocols are being studied in kidney transplantation; four major trials have attempted to withdraw immunosuppressive treatment with various successes. The common theme in all four trials is the use of radiation treatment and donor cell transplantation. The knowledge gained from these trials can provide valuable insight into the development of a VCA tolerance protocol. Despite similarities, VCAs present additional barriers compared to kidney allografts regarding tolerance induction. VCA donors are likely to be deceased, which limits the time for significant pre-conditioning. VCA donors are also more likely to be human leukocyte antigen–mismatched, which means that tolerance must be induced across major immunological barriers. This review also explores adjunct therapies studied in large animal models that could be the missing element in establishing a safe and stable tolerance induction method.

A systematic review of immunomodulatory strategies used in skin-containing preclinical vascularized composite allotransplant models

BACKGROUND

Acute rejection remains a vexing problem in vascularized composite allotransplantation (VCA). Available immunosuppressive regimens are successful at minimizing alloimmune response and allowing VCA in humans. However, repeated rejection episodes are common, and systemic side effects of the current standard regimen (Tacrolimus, MMF, Prednisone) are dose limiting. Novel immunomodulatory approaches to improve allograft acceptance and minimize systemic toxicity are continuously explored in preclinical models. We aimed to systematically summarize past and current approaches to help guide future research in this complex field.

METHODS

We conducted a systematic review of manuscripts listed in the MEDLINE and PubMed databases. For inclusion, articles had to primarily investigate the effect of a therapeutic approach on prolonging the survival of a skin-containing preclinical VCA model. Non-VCA studies, human trials, anatomical and feasibility studies, and articles written in a language other than English were excluded. We followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines.

RESULTS

The search retrieved 980 articles of which 112 articles were ultimately included. The majority of investigations used a rat model. An orthotopic hind limb VCA model was used in 53% of the studies. Cell and drug-based approaches were investigated 58 and 52 times, respectively. We provide a comprehensive review of immunomodulatory strategies used in VCA preclinical research over a timeframe of 44 years.

CONCLUSION

We identify a transition from anatomically non-specific to anatomical models mimicking clinical needs. As limb transplants have been most frequently performed, preclinical research focused on using the hind limb model. We also identify a transition from drug-based suppression therapies to cell-based immunomodulation strategies.

Local FK506 implants in non-human primates to prevent early acute rejection in vascularized composite allografts

Background

Previous vascularized composite allograft (VCA) studies from our laboratory have shown that topical FK506 delivery in non-human primates (NHPs) was limited by inadequate dermal penetration and rejection persisted. Herein, we report the first utilization of FK506 via subcutaneously implanted discs to mitigate VCA rejection in NHPs.

Methods

Full major histocompatibility complex (MHC)-mismatched NHP pairs underwent partial-face VCA and FK506 disc implantation along the suture line. All allotransplants were maintained post-operatively for two months on the FK506 discs, methylprednisolone, mycophenolate mofetil, and supplemented with intramuscular FK506 if necessary. Group 1 (n=4) was used for optimization of the implant, while Group 2 (n=3) underwent delayed bone marrow transplantation (DBMT) after two months. VCA skin biopsies and peripheral blood samples were obtained for serial assessment of rejection and mixed chimerism by histopathology and flow cytometry respectively.

Results

In Group 1, two technical failures occurred. Of the remaining two NHPs, one developed supratherapeutic levels of FK506 (50–120 ng/mL) and had to be euthanized on postoperative day (POD) 12. Reformulation of the implant resulted in stable FK506 levels (20–30 ng/mL) up to POD12 when further intramuscular (IM) FK506 injections were necessitated. In Group 2, two NHPs survived to undergo conditioning and one successfully developed chimerism at 2–3 weeks post-DBMT (96–97% granulocytes and 7–11% lymphocytes of recipient-origin). However, all three NHPs had to be terminated from study at POD64, 77 and 86 due to underlying post-transplant lymphoproliferative disorder. All VCAs remained rejection-free up to study endpoint otherwise.

Conclusions

This study shows preliminary results of local FK506 implants in potentially mitigating VCA acute rejection for tolerance protocols based on mixed chimerism approach.

Sensitization and Desensitization in Vascularized Composite Allotransplantation

Vascularized composite allotransplantation (VCA) is a field under research and has emerged as an alternative option for the repair of severe disfiguring defects that result from severe tissue loss in a selected group of patients. Lifelong immunosuppressive therapy, immunosuppression associated complications, and the effects of the host immune response in the graft are major concerns in this type of quality-of-life transplant. The initial management of extensive soft tissue injury can lead to the development of anti-HLA antibodies through injury-related factors, transfusion and cadaveric grafting. The role of antibody-mediated rejection, donor-specific antibody (DSA) formation and graft rejection in the context of VCA still remain poorly understood. The most common antigenic target of preexisting alloantibodies are MHC mismatches, though recognition of ABO incompatible antigens, minor histocompatibility complexes and endothelial cells has also been shown to contribute to rejection. Mechanistically, alloantibody-mediated tissue damage occurs primarily through complement fixation as well as through antibody-dependent cellular toxicity. If DSA exist, activation of complement and coagulation cascades can result in vascular thrombosis and infarction and thus rejection and graft loss. Both preexisting DSA but especially de-novo DSA are currently considered as main contributors to late allograft injury and graft failure. Desensitization protocols are currently being developed for VCA, mainly including removal of alloantibodies whereas treatment of established antibody-mediated rejection is achieved through high dose intravenous immunoglobulins. The long-term efficacy of such therapies in sensitized VCA recipients is currently unknown. The current evidence base for sensitizing events and outcomes in reconstructive transplantation is limited. However, current data show that VCA transplantation has been performed in the setting of HLA-sensitization.

Facial Transplantation: Complications, Outcomes, and Long-Term Management Strategies

Within the past two decades, vascularized facial composite allotransplantation has evolved into a viable option in the reconstructive surgeons' armamentarium for patients with extensive facial disfigurements. As it has expanded the frontiers of microsurgical reconstructive techniques, facial transplantation has come to garner widespread interest within both the medical community and the general public. The procedure has established itself as an amalgamation of the forefronts of reconstructive microsurgery, immunology, and transplantation science. Therein too lies its complexity as multifaceted scientific developments are met with ethical and social issues. Both patients and physicians are faced with the everlasting challenges of immunosuppression regimens and their inherent complications, long-term aesthetic and functional considerations, the role of revision procedures, and the inevitable psychosocial implications. This article reflects on the medical and surgical advancements in facial transplantation surgery and highlights anticipated future challenges. It aims to encourage discussion regarding anticipated barriers to current practice and suggest future directions as we transition into the next phase of facial allograft transplantation.

Pharmacokinetics and Biodistribution of Tacrolimus after Topical Administration: Implications for Vascularized Composite Allotransplantation

AIM

The high doses of oral tacrolimus (TAC) (1,2) necessary to prevent acute rejection (AR) after vascularized composite allotransplantation (VCA) are associated with systemic adverse effects. The skin is the most antigenic tissue in VCA and the primary target of AR. However, the short-term use of topical TAC (Protopic®), as an off-label adjunct to oral TAC, to treat AR episodes pro re nata (PRN), has yielded inconsistent results. There is lack of data on the pharmacokinetics and tissue distribution of topical TAC in VCA, that hampers our understanding of the reasons for unreliable efficacy. Toward this goal, we evaluated the ability of topical TAC to achieve high local tissue concentrations at the site of application with low systemic concentrations.

MATERIALS AND METHODS

We assessed the pharmacokinetics and tissue distribution of topical TAC (Protopic®, 0.03%) after single or repeated topical application in comparison to those after systemic delivery in rats. Animals received a single topical application of TAC ointment (Group 1) or an intravenous (IV) injection of TAC (Group 2) at a dose of 0.5 mg/kg. In another experiment, animals received daily topical application of TAC ointment (Group 3), or daily intraperitoneal (IP) injection of TAC (Group 4) at a dose of 0.5 mg/kg for 7 days. TAC concentrations in blood and tissues were analyzed by Liquid Chromatography-Mass Spectrometry (LC/MS-MS).

RESULTS

Following single topical administration, TAC was absorbed slowly with a Tmax of 4 h and an absolute bioavailability of 11%. The concentrations of TAC in skin and muscle were several folds higher than whole blood concentrations. Systemic levels remained subtherapeutic (< 3 ng/ml) with repeated once daily applications.

CONCLUSION

Topical application of TAC ointment (Protopic®, 0.03%) at a dose of 0.5 mg/kg/day provided high concentrations in the local tissues with low systemic exposure. Repeated topical administration of TAC is well tolerated with no local or systemic adverse effects. This study confirms the feasibility of topical application of TAC for site specific graft immunosuppression and enables future applications in VCA.

A Comparison of Immunosuppression Regimens in Hand, Face, and Kidney Transplantation

BACKGROUND

Authors have speculated that vascularized composite allotransplantation (VCA) recipients may require greater maintenance immunosuppression than solid organ transplant (SOT) recipients due to the higher antigenicity of skin. However, detailed comparisons of VCA and SOT immunosuppression regimens have been limited.

METHODS

Hand and face VCA recipient immunosuppression data were collected through a systematic literature review. Kidney recipient data were obtained through a retrospective chart review of the authors' institution. Prednisone and mycophenolate mofetil (MMF) doses were compared between VCA and kidney recipients at predefined follow-up intervals (<1, 1-5, and >5 y). Tacrolimus target trough levels (TTTL) were compared at follow-up intervals of 1-5 and >5 y, and stratified into our institution's kidney transplant risk-based target ranges (4-6 ng/mL, 6-8 ng/mL) or higher (>8 ng/mL).

RESULTS

Immunosuppression data were available for 57 VCA and 98 kidney recipients. There were no significant differences in prednisone doses between groups at all follow-up intervals. VCA recipient mean MMF dose was significantly greater at <1-y (1.71 ± 0.58 versus 1.16 ± 0.55 gm/d; P = 0.01). For VCA recipients, there was a significant difference (P = 0.02) in TTTL distribution over the three predefined therapeutic ranges (4-6 ng/mL, 6-8 ng/mL, and >8 ng/mL) between 1 and 5 y (24.0%, 20.0%, 56.0%, respectively) and >5 y (28.6%, 42.9%, 28.6%).

CONCLUSIONS

At longer follow-up, VCA and kidney recipients receive comparable MMF/prednisone doses, and most VCA recipients are treated with TTTL similar to kidney recipients. Further research may improve our understanding of VCA's complex risk/benefit ratio, and enhance informed consent.

Costimulation Blockade in Vascularized Composite Allotransplantation

Vascular composite allotransplantation (VCA) is a field under research and has emerged as an alternative option for the repair of severe disfiguring defects that result from infections or traumatic amputation in a selected group of patients. VCA is performed in centers with appropriate expertise, experience and adequate resources to effectively manage the complexity and complications of this treatment. Lifelong immunosuppressive therapy, immunosuppression associated complications, and the effects of the host immune response in the graft are major concerns in VCA. VCA is considered a quality of life transplant and the risk-benefit ratio is dissimilar to life saving transplants. Belatacept seems a promising drug that prolongs patient and graft survival in kidney transplantation and it could also be an alternative approach to VCA immunosuppression. In this review, we are summarizing current literature about the role of costimulation blockade, with a focus on belatacept in VCA.

Toward Development of the Delayed Tolerance Induction Protocol for Vascularized Composite Allografts in Nonhuman Primates

BACKGROUND

Transplantation of vascularized composite allografts is limited mainly by the need for life-long immunosuppression. The consequent side effects and looming specter of chronic rejection portend eventual allograft loss. Development of tolerogenic protocols is thus of utmost importance to the field of vascularized composite allograft transplantation.

METHODS

With a modified delayed tolerance induction protocol, 10 cynomolgus macaques received hand (n = 2) or face vascularized composite allografts across both full and haploidentical major histocompatibility complex barriers before donor bone marrow transplantation at a later date. Protocol and for-cause allograft skin biopsies were performed for immunohistochemical analysis and analysis of donor-recipient leukocyte contribution; mixed chimerism in peripheral blood and in vitro immune responses were assessed serially.

RESULTS

Before bone marrow transplantation, maintenance immunosuppression for 4 months led to lethal complications, including posttransplant lymphoproliferative disorder (in two of four recipients), which necessitated early study termination. Shortening the maintenance period to 2 months was clinically relevant and allowed all subsequent subjects (n = 6) to complete the delayed tolerance induction protocol. Acute rejection developed within the first 2 to 4 weeks after transplantation, with corresponding near-complete turnover of allograft leukocytes from donor to recipient origin, but donor-specific antibodies remained negative. After bone marrow transplantation, mixed chimerism failed to develop, although carboxyfluorescein succinimidyl ester mixed lymphocyte reaction demonstrated generalized unresponsiveness. However, the accrual of subsequent rejection episodes eventually culminated in graft vasculopathy and irreversible allograft loss.

CONCLUSIONS

Despite the various advantages of the delayed tolerance induction protocol, it failed to reliably induce mixed chimerism and thus immunologic tolerance to vascularized composite allografts, given currently available immunosuppression treatment options. Ongoing work shows promise in overcoming these limitations.

Local Immunosuppression for Vascularized Composite Allografts: Application of Topical FK506-TyroSpheres in a Nonhuman Primate Model

Transplantation of vascularized composite allografts (VCAs) provides a means of restoring complex anatomical and functional units following burns and other disfigurement otherwise not amenable to conventional autologous reconstructive surgery. While short- to intermediate-term VCA survival is largely dependent on patient compliance with medication, the myriad of side effects resulting from lifelong systemic immunosuppression continue to pose a significant challenge. Topical immunosuppression is therefore a logical and attractive alternative for VCA. Current formulations are limited though, by poor skin penetration but this may be mitigated by conjugation of immunosuppressive drugs to TyroSpheres for enhanced delivery. Therefore, we investigated the topical application of FK506-TyroSpheres (in the form of a gel dressing) in a clinically relevant nonhuman primate VCA model to determine if allograft survival could be prolonged at reduced levels of maintenance systemic immunosuppression. Six Major Histocompatibility Complex (MHC)-mismatched cynomolgus macaques (Macaca fascicularis) served as reciprocal donors and recipients of radial forearm fasciocutaneous flaps. Standard Bacitracin ointment and FK506-TyroSpheres were applied every other day to the VCAs of animals in groups 1 (controls, n = 2) and 2 (experimental, n = 4), respectively, before gradual taper of systemic FK506. Clinical features of VCA rejection still developed when systemic FK506 fell below 10 ng/ml despite application of FK506-TyroSpheres and prolonged VCA survival was not achieved. However, unwanted systemic FK506 absorption was avoided with TyroSphere technology. Further refinement to optimize local drug delivery profiles to achieve and maintain therapeutic delivery of FK506 with TyroSpheres is underway, leveraging significant experience in controlled drug delivery to mitigate acute rejection of VCAs.

Building a Hand and Upper Extremity Transplantation Program: Lessons Learned From the First 20 Years of Vascularized Composite Allotransplantation

Background: Upper extremity transplantation is a quality-of-life enhancing treatment for select patients with upper extremity loss. This article reviews the preoperative, intraoperative, and postoperative challenges in the upper extremity transplantation process and the lessons learned from the first 2 decades of hand transplantation. Methods: Key components of the author's hand transplantation protocol including patient selection, donor screening, surgical rehearsal, donor procurement, transplantation, immunosuppression, and patient outcome reporting/follow-up are reported to assist other teams who wish to establish a hand transplantation program. Results: There have been many advancements in the first 20 years of hand transplantation including better patient selection criteria, the recent addition of pediatric patients, improved surgical techniques such as the use of virtual surgical planning, and improved immunosuppression protocols. Improvement has also taken place in the tracking and reporting of hand transplant outcomes, but more work is clearly needed to fully define the benefits of transplantation, especially for pediatric patients. Conclusions: Over the past 20 years, significant progress has been made in upper extremity transplantation although a number of challenges remain including how to best document and share outcome measures, optimize immunosuppression, and diagnose/treat rejection. The authors encourage upper extremity transplant programs to report their experience and protocols to advance hand transplantation as standard of care for properly selected individuals.

The Evolving Clinical Presentation of Acute Rejection in Facial Transplantation

Importance

Acute rejection is one of the most frequent complications in facial transplantation, with potentially severe consequences for the recipient if overlooked. Clinical signs, such as erythema or edema, are helpful to diagnose acute rejection in the early follow-up stage; however, it is not well known whether these clinical signs remain reliable markers of acute rejection beyond the second posttransplant year.

Objective

To determine the diagnostic value of clinical signs of acute rejection after facial transplantation over time.

Design, Setting, and Participants

A retrospective, single-center cohort study was conducted of patients who underwent facial transplantation at Brigham and Women's Hospital between April 2009 and October 2014, with up to an 8-year follow-up. Medical records were reviewed until September 30, 2017. The medical records from 104 encounters with 7 patients who underwent partial or full facial transplantation were analyzed for symptoms of rejection, immunosuppressive therapy, and histopathologic findings.

Main Outcomes and Measures

The occurrence of 5 clinical signs of acute rejection were evaluated: erythema, edema, exanthema, suture line erythema, and mucosal lesions. Odds ratios (ORs) were calculated to determine the statistically significant association of these signs with the histopathologic diagnosis of rejection. In addition, tacrolimus blood levels, as a surrogate marker of immunosuppressive therapy, were evaluated.

Results

Of the 7 patients included in the study, 5 were men. The mean follow-up was 66 months (range, 35-101). Of 104 clinical encounters, 46 encounters (44.2%) represented rejection episodes and 58 encounters (55.8%) represented no-rejection episodes. Beyond 2 years posttransplantation, only erythema (OR, 6.53; 95% CI, 1.84-20.11; P = .004) and exanthema (OR, ∞; 95% CI, 2.2-∞; P = .004) were demonstrated to be reliable clinical signs of acute rejection in facial transplantation. There was also a statistically significant association of subtherapeutic tacrolimus levels with late rejection episodes (OR, 3.79; 95% CI, 1.25-12.88; P = .03). In addition, the occurrence of subclinical rejection was more frequent during later follow-up times (7 [24.1%] late rejections vs 1 [5.9%] early rejection). Five of 8 subclinical rejections (62.5%) were associated with subtherapeutic tacrolimus levels.

Conclusions and Relevance

Clinical signs of acute rejection in facial transplantation appear to be of limited diagnostic value, particularly after the second postoperative year. Until alternative biomarkers for rejection are identified, protocol skin biopsies will remain necessary for guiding assessments of allograft rejection.

Level of Evidence

3.

Blood proteome profiling using aptamer-based technology for rejection biomarker discovery in transplantation

Face transplantation is a promising solution for patients with devastating facial injuries who lack other satisfactory treatment options. At the same time, this type of transplantation is accompanied with high risks of acute transplant rejection. The limitations of traditional skin biopsy and the need to frequently monitor the condition of face transplant call for less invasive biomarkers to better diagnose and treat acute rejection. Discovery of peripheral serum proteins accurately reflecting the transplant status would represent a reasonable solution to meet this demand. However, to date, there is no clinical data available to address the feasibility of this approach. In this study, we used the next generation aptamer-based SOMAscan proteomics platform to profile 1305 proteins of peripheral blood serum in twenty-four samples taken from 6 patients during no-rejection, nonsevere rejection, and severe rejection episodes. Also, we provide a detailed description of biosample processing and all steps to generate and analyze the SOMAscan dataset with hope it will assist in performing biomarker discovery in other transplantation centers using this platform.

MMP3 Is a Non-invasive Biomarker of Rejection in Skin-Bearing Vascularized Composite Allotransplantation: A Multicenter Validation Study

Background: There is unmet need for non-invasive immunomonitoring to improve diagnosis and treatment of acute rejection in vascularized composite allotransplantation (VCA). Circulating matrix metalloproteinase 3 (MMP3) was described as a candidate non-invasive biomarker to predict treatment response to acute rejection in clinical VCA. However, larger validation studies are yet to be reported to allow for more definitive conclusions.

Methods: We retrospectively measured MMP3 levels using ELISA in a total of 140 longitudinal serum samples from six internal and three external face transplant recipients, as well as three internal and seven external upper extremity transplant recipients. The control groups comprised serum samples from 36 kidney transplant recipients, 14 healthy controls, and 38 patients with autoimmune skin disease. A linear mixed model was used to study the effect of rejection state (pre-transplant, no-rejection, non-severe rejection (NSR), and severe rejection) on MMP3 levels.

Results: In VCA, MMP3 levels increased significantly (p < 0.001) between pre- and post-transplant no-rejection states. A further increase occurred during severe rejection (p < 0.001), while there was no difference in MMP3 levels between non-severe and no-rejection episodes. A threshold of 5-fold increase from pre-transplant levels could discriminate severe from NSR with 76% sensitivity and 81% specificity (AUC = 0.79, 95% CI = 0.65–0.92, p < 0.001). In kidney transplantation, the MMP3 levels were significantly (p < 0.001) elevated during antibody-mediated rejection but not during T-cell mediated rejection (TCMR) (p = 0.547). MMP3 levels in healthy controls and autoimmune skin disease patients were comparable with either pre-transplant or no-rejection/NSR episodes of VCA patients.

Conclusion: The results of this study suggest that serum MMP3 protein is a promising marker for stratifying patients according to severity of rejection, complementary to biopsy findings.

Achievements and Challenges in Facial Transplantation

: The first facial transplantation in 2005 ushered in a new era in reconstructive surgery, offering new possibilities for the repair of severe disfigurements previously limited by conventional techniques. Advances in allograft design, computerized preoperative planning, surgical technique, and postoperative revisions have helped push the boundaries in this new frontier of vascularized composite allotransplantation. Over the past 12 years, 40 of these procedures have been performed across the world, offering the field the opportunity to reflect on current outcomes. Successes achieved in the brief history of facial transplantation have resulted in a new set of obstacles the field must now overcome. In this review, we aim to highlight the achievements, major challenges, and future directions of this rapidly evolving field.

Graft vasculopathy of vascularized composite allografts in humans: a literature review and retrospective study

Mechanisms of chronic rejection of vascularized composite allografts (VCA) remain poorly understood and likely present along a spectrum of highly varied clinicopathological findings. Across both animal and human VCA however, graft vasculopathy (GV) has been the most consistent pathological finding resulting clinically in irreversible allograft dysfunction and eventual loss. A literature review of all reported clinical VCA cases with documented GV up to December 2018 was thus performed to elucidate the possible mechanisms involved. Relevant data extracted include C4d deposition, donor-specific antibody (DSA) formation, extent of human leukocyte antigen (HLA) mismatch, pretransplant panel reactive antibody levels, induction and maintenance immunosuppression used, the number of preceding acute rejection episodes, and time to histological confirmation of GV. Approximately 6% (13 of 205) of all VCA patients reported to date developed GV at a mean of 6 years post-transplantation. 46% of these patients have either lost or had their VCAs removed. Neither C4d nor DSA alone was predictive of GV development; however, when both are present, VCA loss appears inevitable due to progressive GV. Of utmost concern, GV in VCA does not appear to be abrogated by currently available immunosuppressive treatment and is essentially irreversible by the time of diagnosis with allograft loss a likely eventuality.

Composite tissue allotransplantation: opportunities and challenges

Vascularized composite allotransplants (VCAs) have unique properties because of diverse tissue components transplanted en mass as a single unit. In addition to surgery, this type of transplant also faces enormous immunological challenges that demand a detailed analysis of all aspects of alloimmune responses, organ preservation, and injury, as well as the immunogenicity of various tissues within the VCA grafts to further improve graft and patient outcomes. Moreover, the side effects of long-term immunosuppression for VCA patients need to be carefully balanced with the potential benefit of a non-life-saving procedure. In this review article, we provide a comprehensive update on limb and face transplantation, with a specific emphasis on the alloimmune responses to VCA, established and novel immunosuppressive treatments, and patient outcomes.

Increased levels of circulating MMP3 correlate with severe rejection in face transplantation

Face transplantation is a viable treatment option for carefully selected patients with devastating injuries to the face. However, acute rejection episodes occur in more than 80% of recipients in the first postoperative year. Unfortunately, neither a correlation between histological grades of rejection and anti-rejection treatment nor systemic surrogate markers of rejection in face transplantation are established in clinical routine. Therefore, we utilized next generation aptamer-based SOMAscan proteomics platform for non-invasive rejection biomarker discovery. Longitudinal serum samples from face transplant recipients with long-term follow-up were included in this study. From the 1,310 proteins analyzed by SOMAscan, a 5-protein signature (MMP3, ACY1, IL1R2, SERPINA4, CPB2) was able to discriminate severe rejection from both no-rejection and nonsevere rejection samples. Technical validation on ELISA platform showed high correlation with the SOMAscan data for the MMP3 protein (r_s = 0.99). Additionally, MMP3 levels were significantly increased during severe rejection as compared to no-rejection (p = 0.0009) and nonsevere rejection (p = 0.0173) episodes. Pathway analyses revealed significant activation of the metallopeptidase activity during severe face transplant rejection. This pilot study demonstrates the feasibility of SOMAscan to identify non-invasive candidate biomarkers of rejection in face transplantation. Further validation in a larger independent patient cohort is needed.

Software-based video analysis of functional outcomes of face transplantation

INTRODUCTION

Assessment of outcomes after face transplantation (FT) is necessary to provide sound evidence on the benefits of this life-giving surgery. Current methods for outcomes assessment, however, are imprecise or prone to subjectivity. Software-based video analysis may allow fast, objective and retrospective assessment of restoration of facial movements and functions after FT.

PATIENTS AND METHODS

We recorded videos of 7 subjects before as well as every 3-6 months after facial transplantation. Patients performed the same sequence of facial movements in every video: smile, open mouth, purse lips, wrinkle nose, frown, close eyes, and lift eyebrows. The videos were retrospectively analyzed using EMOTIENT software, which is capable of automatic tracking and detailed measurements of facial movements and expressions. These measurements were subsequently compared to the same patient at different time points, as well as to the normal population.

RESULTS

Open mouth, wrinkle nose and smile functions significantly improved in all patients when compared to pre-transplant functions; this improvement was significant at 3, 6, and 12 months after transplant, respectively. Lip purse, eye closure and frown functions improved by 6, 9, and 18 months after transplantation, respectively; however, improvement in these particular functions was not significantly with respect to pre-transplant. Face transplantation did not improve any of the patients' ability to lift their eyebrows. Most remarkably, mouth opening and smiling functions both reached values comparable to the normal population at 3 and 12 months after transplantation, respectively.

CONCLUSION

Software-based video analysis provides a valuable assessment tool capable of objective, precise and reproducible analysis of facial movements and functions after FT.

Innovations in reconstructive microsurgery: Reconstructive transplantation

In the past 20 years, reconstructive transplantation (RT) has emerged as a viable reconstructive option for carefully selected patients. More than 100 upper extremity and 40 face transplants have been performed worldwide to date. Concomitantly, the portfolio of reconstructive transplantation has been extended by additional procedures such as lower extremities, abdominal wall, neck, uterus, genitourinary, and pediatric transplants. In the present review article, we aim to summarize the current state of knowledge about this exciting field.

Facial restoration by transplantation

Hundred years ago, Sir Harold Gillies laid a foundation to the modern plastic surgery trying to reconstruct facial defects of severely disfigured soldiers of World War I. Some years later, Joseph Murray experimented with rejection of skin grafts aimed for treatment of burned patients who sustained their injuries on battlefields of World War II. In 1954, the acquired expertise and intensive research allowed him to perform the first successful kidney transplantation in the world at Peter Bent Brigham Hospital in Boston. For his achievements in organ transplantation he was awarded Nobel Prize in 1990. The face transplantation appears to be a natural evolution of the work of these two extraordinary plastic surgeons. The first case of partial face transplant from 2005 in France revealed the world that facial restoration by transplantation is superior to conventional reconstruction methods. Since 2009, our team has performed 7 cases of face transplantation at Brigham and Women's Hospital, which is to our best knowledge the largest living single center face transplant cohort in the world. In this article, we want to reflect on the experience with face transplantation at our institution from the past years. We aim to briefly review the key points of the know-how which was given to us from the care of these unique patients.

Outcomes after hand and upper extremity transplantation

Hand and upper extremity transplantation (HUET) has emerged as the most frequently performed reconstructive procedure in the burgeoning field of vascularized composite allotransplantation (VCA). VCA refers to a form of transplant with multiple tissue types that represents a viable treatment option for devastating injuries where conventional reconstruction would be unable to restore form and function. As hand transplantation becomes increasingly more common, discussions on advantages and disadvantages of the procedure seem to intensify. Despite encouraging functional outcomes, current immunosuppressive regimens with their deleterious side-effect profile remain a major concern for a life-changing but not life-saving type of transplant. In addition, a growing number of recipients with progressively longer follow-up prompt the need to investigate potential long-term sequelae, such as chronic rejection. This review will discuss the current state of HUET, summarizing outcome data on graft survival, motor and sensory function, as well as immunosuppressive treatment. The implications of these findings for VCA in terms of achievements and challenges ahead will then be discussed.

Face transplant: long-term follow-up and results of a prospective open study

BACKGROUND

More than 30 face transplantations have been done worldwide since 2005 but no documented long-term follow-up has been reported in the literature. We aimed to answer remaining question about the long-term risks and benefits of face transplant.

METHODS

In this single-centre, prospective, open study, we assessed 20 patients presenting with facial defects. Ten patients were selected, and, after three were secondarily excluded, seven were transplanted: two with neurofibromatosis 1, one with a burn, and four with self-inflicted facial gunshot injuries. We report the long-term outcomes of six face allotransplant recipients at an average of 6 years (range 3·4-9 years) after the transplantation. All admissions to hospital except for planned revisions and immunosuppressive follow-up therapy were reported as adverse events (safety endpoint). Predefined immunological, metabolic, surgical, and social integration endpoints were collected prospectively. Patients underwent quantitative health-related quality of life assessments through Short Form 36 health questionnaires. This study was registered with ClinicalTrials.gov, number NCT00527280.

FINDINGS

Two of seven patients died: one at 65 days due to transplant destruction with concomitant pseudomonas infection and the second at 3·4 years after transplantation by suicide. The six patients alive at long-term follow-up presented with functional transplants. Safety endpoints were related to infection in the first month, acute rejection from 1 day to 7 years after transplantation, or side-effects of immunosuppressive therapy. Recurrent rejection episodes justified maintenance therapy with high-dose steroids at high levels in all patients at last follow-up, yet none of the patients developed diabetes. Three patients were found to have hypertension with one requiring therapy. All patients had a noticeable reduction in glomerular filtration rate. All recipients and their families accepted their transplant. Improvements in social integration and quality of life were highly variable among the patients and depended on baseline levels and psychiatric comorbidities.

INTERPRETATION

These long-term results show the crucial effect of patients' social support and pre-existing psychiatric conditions on the risk-benefit ratio of facial transplantation. Careful preoperative patient selection and long-term postoperative follow-up programmes under strict institutional review board controls should be used for any future grafts of this type.

FUNDING

Protocole Hospitalier de Recherche Clinique (PHRC) National.

Codominant Role of Interferon-γ- and Interleukin-17-Producing T Cells During Rejection in Full Facial Transplant Recipients

Facial transplantation is a life-changing procedure for patients with severe composite facial defects. However, skin is the most immunogenic of all transplants, and better understanding of the immunological processes after facial transplantation is of paramount importance. Here, we describe six patients who underwent full facial transplantation at our institution, with a mean follow-up of 2.7 years. Seum, peripheral blood mononuclear cells, and skin biopsy specimens were collected prospectively, and a detailed characterization of their immune response (51 time points) was performed, defining 47 immune cell subsets, 24 serum cytokines, anti-HLA antibodies, and donor alloreactivity on each sample, producing 4269 data points. In a nonrejecting state, patients had a predominant T helper 2 cell phenotype in the blood. All patients developed at least one episode of acute cellular rejection, which was characterized by increases in interferon-γ/interleukin-17-producing cells in peripheral blood and in the allograft's skin. Serum monocyte chemotactic protein-1 level was significantly increased during rejection compared with prerejection time points. None of the patients developed de novo donor-specific antibodies, despite a fourfold expansion in T follicular helper cells at 1 year posttransplantation. In sum, facial transplantation is frequently complicated by a codominant interferon-γ/interleukin-17-mediated acute cellular rejection process. Despite that, medium-term outcomes are promising with no evidence of de novo donor-specific antibody development.

Vascularized composite allotransplantation: current standards and novel approaches to prevent acute rejection and chronic allograft deterioration

The advent of more potent immunosuppressants led to the first successful human upper extremity transplantation in 1998. At this time, >100 upper extremity transplants, 30 face transplants, and a variety of other vascularized composite allotransplantation (VCA) procedures have been performed around the world. VCA recipients present unique challenges for transplantation. The incidence of acute rejection exceeds 80% in hand and face transplantation and is well documented, whereas reports about antibody-mediated rejection and chronic rejection remain scarce. Immunosuppression protocols commonly used at US centers are derived from solid organ transplantation protocols. Novel approaches to minimize rejections in VCA may include improved HLA matching and considerations toward cytomegalovirus infection status. New graft preservation techniques may decrease immunogenicity prior to transplant. Novel monitoring methods such as valid biomarkers, ultrasound biomicroscopy, and sentinel flaps may enable earlier diagnosis of rejection. Cell-based therapies are being explored to achieve immunosuppressive regimen minimization or even tolerance induction. The efficacy of local immunosuppression in clinical VCA remains controversial. In conclusion, although immunosuppressive strategies adapted from SOT have demonstrated good midterm results, focusing on the unique features of VCA grafts may enable additional, more specific treatment strategies in the future and improved long-term graft outcomes.