Noninvasive Monitoring of Immune Rejection in Face Transplant Recipients

Minimally and Non-invasive Approaches to Rejection Identification in Vascularized Composite Allotransplantation

OBJECTIVE

Rejection is common and pernicious following Vascularized Composite Allotransplantation (VCA). Current monitoring and diagnostic modalities include the clinical exam which is subjective and biopsy with dermatohistopathologic Banff grading, which is subjective and invasive. We reviewed literature exploring non- and minimally invasive modalities for diagnosing and monitoring rejection (NIMMs) in VCA.

METHODS

PubMed, Cochrane, and Embase databases were queried, 3125 unique articles were reviewed, yielding 26 included studies exploring 17 distinct NIMMs. Broadly, NIMMs involved Imaging, Liquid Biomarkers, Epidermal Sampling, Clinical Grading Scales, and Introduction of Additional Donor Tissue.

RESULTS

Serum biomarkers including MMP3 and donor-derived microparticles rose with rejection onset. Epidermal sampling non-invasively enabled measurement of cytokine & gene expression profiles implicated in rejection. Both hold promise for monitoring. Clinical grading scales were useful diagnostically as was reflection confocal microscopy. Introducing additional donor tissue showed promise for preemptively identifying rejection but requires additional allograft tissue burden for the recipient.

CONCLUSION

NIMMs have the potential to dramatically improve monitoring and diagnosis in VCA. Many modalities show promise however, additional research is needed and a multimodal algorithmic approach should be explored.

Defining chronic rejection in vascularized composite allografts - do we have reliable surrogates to look for?

PURPOSE OF REVIEW

Chronic rejection (CR) is a major threat in the field of vascularized composite tissue allografts (VCAs) as it causes graft dysfunction and usually graft loss. Unfortunately, knowledge of CR in VCA is incomplete because of the limited number of VCA recipients, the heterogeneous nature of VCAs and the short follow-up.

RECENT FINDINGS

The diagnosis of CR in VCA has relied on clinical and pathological findings. Clinical changes include graft fibrosis, dyschromia and ischemic/necrotic ulcerations. Pathological changes primarily affect allograft vessels and manifest with graft vasculopathy (i.e. myo-intimal proliferation and luminal narrowing of allograft vessels, leading to graft ischemia). Attempts are made to diagnose CR with non- or minimally-invasive techniques, such as imaging studies (ultrasound biomicroscopy, functional magnetic resonance imaging) and serum biomarkers. These techniques provide interesting results and further insight into the mechanisms of CR in VCA.

SUMMARY

The diagnosis of CR in VCA still relies mainly on clinicopathological graft alterations; unfortunately, these become overt rather late during the rejection process, when reversal of CR is problematic. More recent, minimally- or non-invasive techniques have provided encouraging results, but their usefulness in the diagnosis of CR requires further studies. These data highlight the paramount importance of CR prevention.

Methods of ex vivo analysis of tissue status in vascularized composite allografts

Vascularized composite allotransplantation can improve quality of life and restore functionality. However, the complex tissue composition of vascularized composite allografts (VCAs) presents unique clinical challenges that increase the likelihood of transplant rejection. Under prolonged static cold storage, highly damage-susceptible tissues such as muscle and nerve undergo irreversible degradation that may render allografts non-functional. Skin-containing VCA elicits an immunogenic response that increases the risk of recipient allograft rejection. The development of quantitative metrics to evaluate VCAs prior to and following transplantation are key to mitigating allograft rejection. Correspondingly, a broad range of bioanalytical methods have emerged to assess the progression of VCA rejection and characterize transplantation outcomes. To consolidate the current range of relevant technologies and expand on potential for development, methods to evaluate ex vivo VCA status are herein reviewed and comparatively assessed. The use of implantable physiological status monitoring biochips, non-invasive bioimpedance monitoring to assess edema, and deep learning algorithms to fuse disparate inputs to stratify VCAs are identified.

Quantification of Facial Allograft Edema During Acute Rejection: A Software-Based 3-Dimensional Analysis

BACKGROUND

Acute rejection (AR) is a common complication in facial transplant (FT) patients associated with allograft edema and erythema. Our study aims to demonstrate the feasibility of using software-based 3-dimensional (3D) facial analysis to quantify edema as it resolves during/after AR treatment in an FT patient.

METHODS

Our patient is a 23-year-old man who underwent a face and bilateral hand allotransplant in August 2020. The Vectra H1 (Canfield, Fairfield, NJ) portable scanner was used to capture 3D facial images at 8 time points between postoperative day (POD) 392 and 539. The images were analyzed with the Vectra Software using a rejection-free image (POD 539) as a control.

RESULTS

Edema increased in the periorbital, lower third, and submandibular regions before AR treatment (POD 392-415). At POD 448, total facial edema was reduced to near baseline values in response to plasmapheresis and thymoglobulin (+156.94 to +28.2 mL). The fastest and most notable response to treatment was seen in the periorbital region, while some edema remained in the submandibular (+19.79 mL) and right lower third (+8.65 mL) regions. On POD 465, after the initial improvement, the edema increased but was resolved with steroid use. Facial edema did not correlate with the histopathological evaluation in our patient.

CONCLUSIONS

We demonstrated the feasibility of analyzing 3D facial images to quantify edema during/after AR treatment in an FT patient. Our analysis detected edema changes consistent with AR followed by an improvement after treatment. This technology shows promise for noninvasive monitoring of FT patients.

Software-based Detection of Acute Rejection Changes in Face Transplant

BACKGROUND

 An objective, non-invasive method for redness detection during acute allograft rejection in face transplantation (FT) is lacking.

METHODS

 A retrospective cohort study was performed with 688 images of 7 patients with face transplant (range, 1 to 108 months post-transplant). Healthy controls were matched to donor age, sex, and had no prior facial procedures. Rejection state was confirmed via tissue biopsy. An image-analysis software developed alongside VicarVision (Amsterdam, Netherlands) was used to produce R, a measure of differences between detectable color and absolute red. R is inversely proportional to redness, where lower R values correspond to increased redness. Linear mixed models were used to study fixed effect of rejection state on R values. Estimated marginal means of fitted models were calculated for pairwise comparisons.

RESULTS

 Of 688 images, 175, 170, 202, and 141 images were attributable to Banff Grade 0,1,2, and 3, respectively. Estimated change in R value of facial allografts decreased with increasing Banff Grade (p = 0.0001). The mean R value of clinical rejection (Banff Grade ⅔) (16.67, 95% Confidence Interval [CI] 14.79-18.58) was lower (p = 0.005) than non-rejection (Banff Grade 0/1) (19.38, 95%CI 17.43-21.33). Both clinical and non-rejection mean R values were lower (p = 0.0001) than healthy controls (24.12, 95%CI 20.96-27.28).

CONCLUSION

 This proof-of-concept study demonstrates that software-based analysis can detect and monitor acute rejection changes in FT. Future studies should expand on this tool's potential application in telehealth and as a screening tool for allograft rejection.

Facial Transplantation: Principles and Evolving Concepts

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Appreciate the evolution and increasing complexity of transplanted facial allografts over the past two decades. 2. Discuss indications and contraindications for facial transplantation, and donor and recipient selection criteria and considerations. 3. Discuss logistical, immunologic, and cost considerations in facial transplantation, in addition to emerging technologies used. 4. Understand surgical approaches and anatomical and technical nuances of the procedure. 5. Describe aesthetic, functional, and psychosocial outcomes of facial transplantation reported to date.

SUMMARY

This CME article highlights principles and evolving concepts in facial transplantation. The field has witnessed significant advances over the past two decades, with more than 40 face transplants reported to date. The procedure now occupies the highest rung on the reconstructive ladder for patients with extensive facial disfigurement who are not amenable to autologous reconstructive approaches, in pursuit of optimal functional and aesthetic outcomes. Indications, contraindications, and donor and recipient considerations for the procedure are discussed. The authors also review logistical, immunologic, and cost considerations of facial transplantation. Surgical approaches to allograft procurement and transplantation, in addition to technical and anatomical nuances of the procedure, are provided. Finally, the authors review aesthetic, functional, and psychosocial outcomes that have been reported to date.

The 2020 Facial Transplantation Update: A 15-Year Compendium

Over the past 15 years, landmark achievements have established facial transplantation (FT) as a feasible reconstructive option for otherwise irreparable craniofacial defects. However, as the field matures and long-term outcomes begin to emerge, FT teams around the world are now facing new challenges. Data for this review were identified by searches of the PubMed/MEDLINE database from inception through August 2020. All English-language articles pertaining to FT were included. Significant advances in candidate selection, technology, operative technique, posttransplant care, and immunosuppressive management have contributed to the tremendous expansion of the field, culminating in the execution in the past 3 years of 2 facial re-transplantations, and most recently the world’s first successful combined face and double hand transplant in August 2020. Despite these achievements, the allograft donor pool remains limited, with long wait times, requiring surgical experimentation with cross-sex FT. Immunosuppressive management has improved, but significant adverse events continue to be reported. Most recently, the COVID-19 pandemic has placed an unprecedented strain on the healthcare system, with various implications for the practice of reconstructive transplantation. In this article, we provide the most comprehensive and up-to-date FT review, highlighting fundamental lessons learned and recent advancements, while looking toward the challenges ahead. Over the past 15 years, extensive multidisciplinary efforts have been instrumental to the establishment of FT as a feasible reconstructive option. As novel challenges are beginning to emerge, continued collaborative and multispecialty research efforts are needed to further this field.

Facial Transplantation

Facial transplantation represents a unique surgical solution for challenging facial injury patterns in which conservative reconstructive techniques fail to provide a satisfactory functional and aesthetic result. With advances in the field of vascularized composite allotransplantation over the past 15 years, more than 40 of these procedures have been performed worldwide with two recent reports of facial re-transplantation. In this article we discuss the multidisciplinary approach that is required for successful transplantation as well as the surgical techniques used and postoperative management. With ongoing research, recent technological innovation, and increased efforts to promote greater generalizability and transparency in this field, patients with these complex injuries will continue to see improvements in their treatment options, and thus quality of life.

Noninvasive evaluation of intragraft immune responses in upper extremity transplantation

In vascularized composite allotransplantation (VCA), invasive tissue biopsies remain the gold standard in diagnosing rejection carrying significant morbidity. We aimed to show feasibility of tape-stripping for noninvasive immune monitoring in VCA. Tape-stripping was performed on allografts and native skin of upper extremity transplant recipients. Healthy nontransplanted individuals served as controls. The technique was also used in swine on naïve skin in nontransplanted animals, native skin of treated, transplanted swine, nonrejecting VCAs, and rejecting VCAs. Extracted protein was analyzed for differences in cytokine expression using Luminex technology. Significantly decreased levels of INFγ and IL-1Ra were seen between human allograft samples and native skin. In swine, rejecting grafts had increased IL-1Ra compared to naïve and native skin, decreased levels of GM-CSF compared to native skin, and decreased IL-10 compared to nonrejecting grafts. Unsupervised hierarchical clustering revealed rejecting grafts separated from the nonrejecting (P = 0.021). Variable importance in projection scores identified GM-CSF, IL-1Ra, and IL-2 as the most important profiles for group discrimination. Differences in cytokine expression are detectable in human VCA patient native skin and VCA graft skin using a noninvasive tape-stripping method. Swine studies suggest that differences in cytokines between rejecting and nonrejecting grafts are discernable.

Long-term outcome after hand and forearm transplantation - a retrospective study

Between 2000 and 2014, five patients received bilateral hand (n = 3), bilateral forearm (n = 1), and unilateral hand (n = 1) transplants at the Innsbruck Medical University Hospital. We provide a comprehensive report of the long-term results at 20 years. During the 6-20 years follow-up, 43 rejection episodes were recorded in total. Of these, 27.9% were antibody-related with serum donor-specific alloantibodies (DSA) and skin-infiltrating B-cells. The cell phenotype in rejecting skin biopsies changed and C4d-staining increased with time post-transplantation. In the long-term, a change in hand appearance was observed. The functional outcome was highly depending on the level of amputation. The number and severity of rejections did not correlate with hand function, but negatively impacted on the patients´ well-being and quality of life. Patient satisfaction significantly correlated with upper limb function. One hand allograft eventually developed severe allograft vasculopathy and was amputated at 7 years. The patient later died due to progressive gastric cancer. The other four patients are currently rejection-free with moderate levels of immunosuppression. Hand transplantation remains a therapeutic option for carefully selected patients. A stable immunologic situation with optimized and individually adopted immunosuppression favors good compliance and patient satisfaction and may prevent development of DSA.

Local immunosuppression in vascularized composite allotransplantation (VCA): A systematic review

BACKGROUND

Local immunosuppression in vascularized composite allotransplantation (VCA) aims to minimize immunosuppressant-related toxic and malignant side effects. Promising allograft survival data have been published by multiple workgroups. In this systematic review, we examine preclinical animal studies that investigated local immunosuppression in VCA.

MATERIAL AND METHODS

We conducted a systematic review of manuscripts listed in the MEDLINE and PubMed database concerning preclinical VCA models. Papers included had to be available as full-text and written in English. Non-VCA studies, human trials, and studies using cell-based therapy strategies were excluded. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Literature research retrieved 980 articles. Ten studies published between 2010 and 2019 met the inclusion and exclusion criteria. Seven out of ten articles demonstrated a significant prolongation of allograft survival by using local immunosuppression. Five articles employed tacrolimus (TAC) as the main immunosuppressive agent. Seven studies performed hind-limb VCA in a rat model.

CONCLUSION

The easily accessible location of skin containing VCAs makes it an ideal candidate for local immunosuppression. Published preclinical data are very promising in terms of improved allograft survival and reduced systemic toxicity.

Biomaterials for topical and transdermal drug delivery in reconstructive transplantation

Lifelong systemic immunosuppression remains the biggest challenge in vascularized composite allotransplantation (VCA) due to the adverse effects it causes. Since VCA is a life-enhancing procedure as compared with solid organ transplant which is life-saving; one needs to weigh the benefits and risks carefully. Thus, there is a huge unmet clinical need to design biomaterial-based vehicles that can deliver drugs more efficiently, topically and locally to eliminate adverse effects of systemic immune suppression. This review discusses several biomaterial-based systems that have been carefully designed, conceived and attempted to make VCA a more patient compliant approach. Variety of promising preclinical studies has shown the feasibility of the approaches, and clinical trials are required to bridge the gap. Several challenges for the future and new approaches have been discussed.

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.

Noninvasive Monitoring of Allograft Rejection Using a Novel Epidermal Sampling Technique

Supplemental Digital Content is available in the text.

Despite promising short- and long-term results to date in vascularized composite allotransplantation (VCA), acute rejection remains the most common major complication in recipients. Currently, diagnosis of acute rejection relies on clinical inspection correlated with histopathological analysis. However, disagreement exists regarding the value of full-thickness skin and mucosal biopsies and histopathology remains semiquantitative, subject to sampling bias, and prone to intra- and inter-observer variabilities. Additionally, biopsies may cause infection, scarring, and/or potentially incite rejection through immune activation after injury. Noninvasive methods to diagnose rejection represent a critical unmet need for the emerging field of VCA. Here, we propose a novel technique utilizing skin stripping of the epidermis and subsequent molecular analysis to detect known markers of acute rejection. Using a small animal VCA model, we sought to validate our epidermal sampling technique as a noninvasive diagnostic test for acute rejection.

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.

Face Transplant: Status of Current Supporting Technology to Plan and Perform the Operation and Monitor the Graft in the Postoperative Period

Face transplant has rapidly advanced since the first operation in 2005, and to date, 40 partial or full-face transplants have been performed. The safety and efficacy of this operation are aided at all phases by supporting technologies. These include advanced imaging techniques to plan the operation, devices to monitor the flap in the immediate perioperative period, and noninvasive imaging and serum markers to monitor for acute and chronic rejection. Some of the technologies, such as those used in the immediate perioperative period, have extensive evidence supporting their use, whereas those to detect acute or chronic rejection remain investigational. The technologies of today will continue to evolve and make the operation safer with improved outcomes; however, the most significant barrier for face transplant continues to be immunologic rejection.

Neoadjuvant peptide receptor radionuclide therapy and modified multivisceral transplantation for an advanced small intestinal neuroendocrine neoplasm: an updated case report

Small intestinal neuroendocrine neoplasms (SI-NEN) frequently metastasise to regional lymph nodes, and surgery is the mainstay of therapy for such patients. However, despite the possible use of advanced surgical techniques, the resection of both primary and locoregional diseases is not always attainable. Intestinal and multivisceral transplantation has been performed in a small number of patients with conventionally nonresectable, slow-growing tumours threatening the mesenteric root but has remained controversial. The use of donor skin in “sentinel flaps” in transplantation theoretically offers advantages in tailoring immunosuppression and monitoring for rejection. We represent (with extended follow-up) the first case of a patient with inoperable extensive mesenteric metastases from SI-NEN, who underwent neoadjuvant peptide receptor radionuclide therapy before a modified multivisceral transplant with a concomitant vascularised sentinel forearm flap. At 48 months after transplantation, our patient remained at full physical activity with no evidence of disease recurrence on either tumour biochemistry or radiological imaging.

Reflections on a Decade of Face Transplantation

On November 27, 2005, Isabelle Dinoire underwent the world's first partial face transplant in Amiens (France) after a dog attack had left her face severely disfigured. The abrupt surgical leap found the medical community and society unprepared to deal with the scientific, ethical, and societal implications of a surgical procedure that was striving to transition from sci-fi novels to science. Today, 10 years and over 35 transplants later, public opinion has become accustomed to the concept of "face restoration" through transplantation. However, face transplantation is far from being a safe "routine" surgery and the science behind it is still mostly unknown. Patients and multidisciplinary teams of physicians confront daily medical challenges, life-threatening risks, and personal struggle that only in part come to light. Could (or should) this be the laborious, uncertain, and high-risk trajectory of disruptive medical innovation? Over the last decade, some medical discoveries and surgical advancements in the field have been closely accompanied by partial regulatory frameworks, intense ethical discussions, and meaningful changes in social beliefs across cultures and continents. Yet, a very long way is to come and the questions we still have today greatly outweigh the answers we can offer. Here, we take the chance of the 10-year anniversary of face transplantation to reflect on the path traveled and to look forward to the challenges lying ahead.

The Influence of Timing and Frequency of Adipose-Derived Mesenchymal Stem Cell Therapy on Immunomodulation Outcomes After Vascularized Composite Allotransplantation

BACKGROUND

Cellular therapies for immunomodulation in vascularized composite allotransplantation (VCA) have gained importance due to their potential for minimization of immunosuppression. Adipose-derived (AD) mesenchymal stem cells (MSCs) especially have shown encouraging potential. We investigated the influence of timing and frequency of AD-MSC treatment on immunologic and graft survival as well as graft vasculopathy outcomes after VCA.

METHODS

Lewis rats received full-mismatched Brown Norway rat hindlimb transplants. Recipient animals were assigned to groups receiving donor-derived AD-MSCs (10 cells/animal) either on postoperative day (POD) 1, POD 4, or repeatedly on POD 4, 8, and 15, and compared to untreated controls.

RESULTS

Although AD-MSC administration on POD 1 or POD 4, 8, and 15 resulted in 50% long-term graft acceptance, recipients treated on POD 4, and controls rejected before POD 50. All treated animals revealed peripheral blood chimerism (4 weeks), most pronounced after repetitive cell administration (12.92% vs 5.03% [POD 1] vs 6.31% [POD 4]; P < 0.05; all P < 0.01 vs control 1.45%). Chimerism was associated with the generation of regulatory T cells (CD4CD25FoxP3). In vitro mixed lymphocyte reactions revealed modulation of the recipient immune response after AD-MSC treatment. Graft arteries at end point revealed significant differences of arterial intimal thickness between rejecting and AD-MSC-treated animals (P < 0.01).

CONCLUSIONS

Taken together, our results point to the potential for repetitive AD-MSC administration in improving outcomes after VCA. Future studies are warranted into optimization of the dosing and frequency of AD-MSC therapy, either alone or used in, combination with other cell therapies (such as hematopoietic stem cells or bone marrow-derived MSC or dendritic cells) for optimization of appropriate conditioning or maintenance regimens.

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.