Composite tissue allotransplantation

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Journal of Investigative Surgery, 16:193–201, 2003Copyright ©c Taylor & Francis Inc.ISSN: 0894-1939 print / 1521-0553 onlineDOI: 10.1080/08941930390215006

Invited Review

Composite Tissue Allotransplantation

Chau Tai, MD,Marat Goldenberg, MD,Kevin M. Schuster, MD,Brian R. Kann, MD,and Charles W. Hewitt, PhDDivision of Surgical Research,Cooper Health System, UMDNJ,Robert Wood Johnson MedicalSchool, Camden, New Jersey,USA

ABSTRACT Composite tissue allotransplantation (CTA) recently tookits first steps in the clinical arena in 1998 with the successful hand trans-plant performed in Lyons, France. That single operation representeda culmination of many years of laboratory research in multiple fieldsinvolving integumentary/musculoskeletal transplantation. Here we re-view the prerequisite developments in the field of immunology, mi-crosurgery, and pharmacotherapy that helped bring CTA to clinicalreality. This new field still has many unanswered questions which areaddressed below. Additionally, new evolving research in CTA is alsodiscussed.

KEYWORDS composite tissue allotransplantation, graft-vs-host disease, handtransplant, tolerance, vascularized bone marrow

Composite tissue allotransplantation (CTA) involves the transplan-tation of various tissues including integumentary/musculoskele-tal, nerves, and vascular tissues, as opposed to a single separate

organ in conventional solid organ transplantation (SOT). An exampleof CTA is limb transplantation, in which the transplanted graft includesskin, muscle, nerve, blood vessels, and bone. In SOT, such as a liver orkidney, allograft function is defined by the biochemical and physiologicproperties of that particular organ. On the other hand, the function andthe immunologic properties of the composite tissue transplant are moredifficult to define, because each individual component tissue possesses itsown unique characteristics that ultimately affect the successful outcomeof the transplant.

The indications for solid organ transplantation are straightforwardand little controversy exists as to whether or not whole-organ trans-plants should be performed. They are designed to restore the physio-logic function of the particular organ, preserve life, and improve thequality of life. In contrast, most applications of CTA predominantly im-prove the quality of life for non-life-threatening conditions and aim torestore anatomic, cosmetic, and functional integrity. The benefits gath-ered by such procedures have to be balanced against the morbidity

Received 18 April 2002;accepted 12 February 2003.

Address correspondence to CharlesW. Hewitt, Director of SurgicalResearch, Cooper Health System,UMDNJ, Robert Wood JohnsonMedical School, 3 Cooper Plz, Ste 411,Camden NJ 08103, USA. E-mail:[email protected]

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of the surgical procedure itself and long-term im-munosuppression therapy.

HISTORICAL PERSPECTIVE

The concept of limb transplantation dates back asfar as the 4th century A.D. The legend of twin saintsCosmas and Damien described the restoration of anextremity by miraculous transplantation from a ca-daver. This legend, well known in the transplant com-munity, has represented the profound desire of hu-mankind to achieve successful transplantation withfull graft tolerance. Scientific research on transplan-tation began in the early 1870s with several reportsof allogeneic skin graft attempts that met with vari-able successes [1]. Decades later in 1918, Massonfirst introduced the importance of donor–recipientcompatibility [2]. However, this concept remainedcontroversial until about 1930, when it became gen-erally accepted that allogeneic skin transplants pre-dictably rejected as opposed to syngeneic grafts. In1944, motivated by the needs of burned pilots of theRoyal Air Force, Peter Medawar performed a seriesof skin allograft experiments using a rabbit modelwith the collaboration of Thomas Gibson, a plasticsurgeon [3, 4]. These works, and others, representedthe groundbreakings in transplant immunology thatset the stage for subsequent developments.

With advancements in vascular and microsurgi-cal techniques as mentioned by Murray for variousorgan transplants [5], composite transplant modelsbegan appearing in the literature in the 1960s. Oneof the models first introduced by Schwind [6], therat hindlimb allograft served as a popular modelfor many researchers in CTA. Others models sub-sequently developed included the canine hindlimb[7], hemimandibular graft in the rabbit and in themonkey [8, 9], laryngeal transplant in the rat [10],and hand allografts in the pig and primate [11,12]. Clearly, technical hurdles have become man-ageable with the aid of microsurgical techniques andinstrumentation.

The immunologic barriers presented a formidablechallenge to CTA. In an attempt to understandand manipulate the dynamics of the immune sys-tem, researchers studied different methods of tol-

erance induction. In 1976, Poole et al. pioneeredusing immunologic enhancement prior to perform-ing orthotopic limb transplants in rats [13]. Usingrecipient-derived antidonor antiserum, prolonged al-lograft survival was achieved by preoperative pas-sive immunization. Whole blood administration wasalso attempted as a way of inducing transplant toler-ance, though without benefit in rat hindlimb trans-plantation [14]. Donor irradiation also prolongedthe survival of vascularized limb tissue allografts,thought the grafts ultimately rejected [15]. So far, nomeans of tolerance induction have been clinicallypractical.

An alternative route to prevent graft rejection isvia immunosuppression with systemic medication.Limb allografts present an array of antigenic tissuesthat theoretically may require significantly higherdoses of immunosuppression for graft survival [5,16]. In 1979, Doi achieved long-term graft survivalin two inbred strains of rats that had a strong anti-genic mismatch at the major histocompatibility com-plex by using azathioprine and prednisolone [17].However, all transplanted limbs ultimately rejected.The cyclosporine A (CsA) era began in the late 1970swhen its immunosuppressive characteristics were dis-covered by Borel [18], and facilitated huge advancesin SOT and CTA. CsA suppresses the immune re-sponse by inhibiting signal transduction pathways ofcalcineurin, a serine/threonine phosphatase. Inhibi-tion of the target molecule in the cytosol completelyblocks the translocation of nuclear factor of activatedT cells (NF-AT), resulting in a failure to activate thegenes regulated by the NF-AT transcription factor.These genes include those required for B-cell stimu-lation (IL-4) and CD40 ligand as well as those nec-essary for T-cell proliferation (IL-2) [19]. Black et al.successfully performed the first hindlimb allotrans-plants in rats across a strong antigenic mismatch us-ing only CsA for immunosuppression in 1982 [20].Their initial study prolonged allograft survival com-pared to the control group (18 days) to an averageof 101 days, and a subsequent study demonstratedan even longer survival of up to 225 days [21]. Withthe discovery of new immunosuppressants and theirwide clinical application in SOT, these drugs broughtthe reality of clinical CTA even closer.

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IMMUNOSUPPRESSION INCOMPOSITE TISSUE

ALLOTRANSPLANTATION

Although the technical feasibility of CTA wasdemonstrated over 20 years ago, clinical applica-tion was delayed due to the side effects of the im-munosuppression regimens and the lack of a goodanimal model comparable with human physiology.Through the simultaneous developments of new andmore effective drugs and the preclinical CTA ani-mal trials, human hand tranplantation was finallyrealized.

Glucocorticoids have served as a mainstay in im-munosuppressive regimens, though they are unsuit-able for use as solo agents due to increased side ef-fects. Early successes of CsA in preventing CTA re-jection generated optimism among researchers. Us-ing the rat hindlimb CTA model, Furnas et al. usedlong-term CsA therapy postoperatively (8 mg/kg/dayfor the first 20 days followed by a maintenance doseof only 8 mg/kg twice a week) and reported one outof five recipients surviving without signs of rejectionfor more then 400 days [22]. Three of the remain-ing four rats survived 66–238 days postoperatively.In the same rat model, Hewitt et al. constructed adose-response curve for CsA using low-dose CsA(4 mg/kg/day) for 20 days and observed purposefulwithdrawal to painful stimulus of the transplantedlimb up to 65 days posttransplant. At 8 mg/kg/dayfor 20 days, grafts survived an average of 74 days [23].In a follow-up study, this group demonstrated thatcomposite tissue allografts in the rat could achieveindefinite survival with low to moderate amounts ofCsA (8 mg/kg/day subcutaneously for 20 days fol-lowed by 8 mg/kg/day orally). With that regimenthe animals were able to maintain the allograft untilthe time of necropsy [24].

In primate studies, however, very high doses ofCsA were necessary to control CTA rejection. Hoviuset al. performed partial limb allotransplants in rhe-sus monkeys that received steroids and CsA at25 mg/kg/day [25]. In spite of this therapy, 10 of12 monkeys developed graft rejection. Other inves-tigators produced similar results, and it was thoughtthat clinical CTA may be prohibitive based on the

toxic effects of immunosuppression in the primatemodels.

The development of mycophenolate mofetil(MMF), tacrolimus (FK506), sirolimus, and antibodyimmunosuppression continued to fuel the successfulpursuit of human CTA. MMF is an antimetabolitethat has largely replaced azathioprine. It is an in-hibitor of de novo purine synthesis and preferentiallyinhibits both T- and B-cell proliferation. It has beenused to reverse renal allograft rejection, and severalexperiments have indicated that it helps to preventlong-term rejection of all of the components of com-posite tissue allografts, including the skin [26]. Ben-haim demonstrated that the combination of CsA andMMF allowed a lowered CsA dose and was superiorto using each drug separately [26, 27].

Like CsA, FK506 also inhibits calcineurin via theFK binding protein [28]. Using FK506 as the primarytherapy, Buttemayer et al. showed rejection-free sur-vival up to 300 days postoperatively in rat hind limballografts across a major antigenic mismatch [29]. Inthis experiment the animals received a 2-mg/kg/ddose for 14 days followed by 2 mg/kg twice a week.However, long-term animals did show mild signs ofrejection. Complications of the immunosuppressionwere frequent, and bacterial pneumonia ultimatelycaused the death of all long-term animals.

Sirolimus is a TOR (target of rapamycin) in-hibitor that also mediates IL-2 postreceptor signal-ing, though its immunosuppressive effects differsfrom CsA and FK506. It has been shown to be highlysynergistic with the latter compounds, enabling re-ductions in toxicity in renal transplant patients [30].Both polyclonal and monoclonal antibodies (e.g.,Orthoclone OKT3) have been used as rescue drugsin acute rejection for SOT [31]. The toxicities ofincrease viral infections, cytokine release syndrome,and potentiation of lymphoproliferative disease limittheir use on selected cases, but they are still im-portant tools in the armamentarium. Though notcurrently used in CTA, these compounds’ demon-strated efficacies in preserving SOT grafts will cer-tainly lend themselves to use in the future forCTA.

In investigating efficacies of these agents, it isimportant to select an appropriate animal model.

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Among the multiple CTA animal models, the swinedemonstrated an immune response to pharma-cotherapy most similar to the human [32]. Basedon the swine model, the combination drug regi-men for the first U.S. hand transplant recipient con-sisted of prednisone, tacrolimus, and topical agents[33].

FUNCTIONAL RECOVERY

Composite tissue allotransplantation cannot beconsidered successful unless it results in significantfunctional recovery of the allograft. A limb with sub-optimal motor and sensory function may lead tomore harm than good, as seen in patients with dia-betic neuropathies. Thus far in human hand trans-plants, motor and sensory recovery has not beencomplete but allows good function of the allografts.Measurements of progress included range of motion,grip and pinch strength, Tinel sign, and the Semmes–Weinstein and Carroll tests [34]. The latter test in-corporates mobility and motor and sensory functionin the functional performance to reflect the abilityto perform activities of daily living. The Louisvillehand transplant recipient scored 52/99 on the Car-roll test at 12 months, while the Guangzhou handrecipients demonstrated 65/99 and 75/99 functionalrecovery at 7 months [34]. In other words, startingfrom a missing limb, the recipients are now able tofeed, brush, write, and tie their shoes. To maximizefunctional recovery, the need for prolonged rehabil-itation and physical therapy cannot be understated,requiring the dedication of both the medical teamand the patient.

Intrinsic in functional recovery is the regenerationof axonal innervations. Mackinnon et al. performednerve allografts in rats and monkeys using CsA treat-ment and demonstrated restoration of muscle func-tion in both groups [35]. When immunosuppres-sion was discontinued, donor Schwann cells were re-jected but neural function persisted. This finding wasthought to be due to the host’s own axonal regenera-tion, which in time replaced donor axons that servedas initial conduits. Thus, only limited immunosup-pression may be required for nerve allografting tobridge the interim of host axonal regeneration. This

approach came to clinical fruition when Mackinnonperformed a successful long nerve allograft in a 12-year-old boy with severe posterior tibial nerve injury[36]. In the context of CTA, this suggests that the ner-vous tissue may not be the component that requireslong-term immunosuppression.

GRAFT-VERSUS-HOST DISEASE ANDTHE VASCULARIZED BONE

MARROW TRANSPLANT

A unique component of CTA is the transfer ofimmunocompetent donor cells via the bone mar-row and lymph nodes. This raises the theoreticalproblem of graft-versus-host disease (GVHD) wherethe donor immune cells reject the host. Yazdi et al.used a parental to F1-hybrid rat hindlimb transplantmodel across a semi-allogeneic barrier to study pos-sible GVHD without immunosuppression [37]. Allanimals developed significant lymphoid chimerismover time. Thirty-seven and one-half percent ofthe rats developed a wasting syndrome consistentwith GVHD and showed high levels of chimerism(60.2%). The remaining fraction of animals didnot develop GVHD, became immunologically tol-erant, and exhibited stable low levels of chimerism(18.3%).

The role of chimerism and GVHD in human CTAremains unknown. In the case of clinical hand trans-plantation, one graft was irradiated in order to reducethis potential problem. Thus far, no recipients havedeveloped GVHD, nor demonstrated chimerism byflow cytometry [34]. The hypothesis is that a handgraft contains only small amounts of functionallyactive donor marrow, and therefore will not signifi-cantly affect a human recipient.

In order to study the immune contribution in aCTA to the host, Suzuki et al. developed an iso-lated vascularized bone-marrow transplant (VBMT)model [38]. Bone-marrow cells are engrafted alongwith their own stromal environment on a vascu-lar pedicle, without muscle and tendon attachmentsas in the CTA. This model is unique from cellu-lar bone-marrow transplantation (CBMT) in severalways. In CBMT, immunoablation is required to de-stroy malignant cells and to create a physical space

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for the donor stem cells to seed and proliferate. Inthe case of VBMT, the cells are delivered withintheir stromal microenvironment, allowing for imme-diate engraftment. As part of a CTA model, it hasbeen demonstrated that systemic immune reconsti-tution is drastically accelerated with a VBMT com-pared to CBMT of a comparable cell volume [39].VBMTs have produced stable mixed T-cell chimerismin semi-allogeneic and allogeneic rats [40, 41] andmay be responsible for the decreased incidence ofGVHD and induction of tolerance in these animalmodels.

The isolated VBMT have several potential uses inthe future. As previously mentioned, it may serveas an adjunct to conventional bone-marrow trans-plants by accelerating immune reconstitution in therecipient. Also, by potentially inducing tolerance viathe process of a stable chimerism, VBMT may beused in conjunction with other solid organ trans-plants to ensure their survival. Further studies areneeded to understand immune interactions with thehost and mechanisms of tolerance induction forVBMT.

COMPOSITE TISSUEALLOTRANSPLANTATION ENTERS

THE CLINICAL ARENA

With the establishment of suitable surgical modelsand the development of novel immunosuppressivetherapies, clinical experience with CTA took its firststeps in the late 1990s. In November 1997, the In-ternational Symposium on Composite Tissue Trans-plantation was held in Louisville, KY, to discuss themain topic of possible human hand allotransplanta-tion. The symposium concluded that with availablemedical regimens and surgical techniques, it was nowappropriate to consider undertaking the procedure[42]. One year later, the first human hand transplantwas performed in Lyons, France [43]. A team of sur-geons transplanted the right hand and a distal fore-arm from a brain-dead donor to a 48-year-old man.The recipient initially received anti-thymocyte glob-ulin (75 mg/day for 10 days), tacrolimus (to achieveblood levels of 10–15 ng/ml for the first month), my-cophenolic acid (2 g/day), and prednisone (250 mg

on day 1, then tapered to 20 mg/day). He was thenmaintained on tacrolimus (5–10 ng/ml), mycophe-nolic acid (2 g/day), and prednisone (15 mg/day at 6months). The patient experienced mild rejection thatcoincided with decreased serum levels of tacrolimus,which clinically reversed with increased dosage. Sixmonths after the transplant, the patient was reportedto have “satisfactory” motor and sensory function[43].

Surgeons at the University of Louisville success-fully duplicated this operation and performed thefirst U.S. hand transplant in January 1999. The pa-tient was a 37-year-old man who lost his left handin 1985. This patient also showed good functionalrecovery, and at 6-month follow-up demonstrateda positive Tinel sign at the level of the fingertips;by 11 months he reported pressure and temperaturesensation in the fingertips. There was evidence ofmuscle innervation at 1 year. Overall the patient re-ported satisfactory function of the hand, althoughfinger flexion and extension were incomplete. Sim-ilar to the initial recipient, this patient also expe-rienced several episodes of moderate acute cellularrejection of the skin graft, which reversed with intra-venous methylprednisolone combined with topicaltacrolimus and clobetasol [44]. Since this time, theFrench team has performed a successful bilateral up-per extremity transplant in January 2000. This patientis reportedly doing well. Other recent clinical en-deavors involving CTA included a laryngeal allograft[45], three vascularized femoral diaphysis transplants[46], and four vascularized knee-joint allotransplants[47].

TOLERANCE INDUCTION IN THEFUTURE

Since CTA is an elective procedure, controversyrevolves around the risks versus benefits, especiallyof the required immunosuppression. Although thedevelopment of pharmacological agents greatly con-tributed to the current success of CTA, the ultimategoal is to achieve tolerance across antigenic barri-ers without the need for immunosuppressive agents.Ideally, the recipient would gain donor specific tol-erance to the graft, but otherwise remain totally

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immunocompetent. The mechanism of tolerance in-duction is not well understood at this point, andcurrent research has focused on three main strate-gies to induce donor-specific tolerance in the recip-ient: genetic matching, costimulatory blockade, anddevelopment of mixed chimerism. Lee et al. havedemonstrated long-term survival of musculoskeletalallografts from MHC-matched (major histocompati-bility), minor antigen mismatched donors using onlya 12-day course of CsA [48]. This model, however,did not contain a cutaneous component. In the clin-ical setting, MHC matching among unrelated indi-viduals would be rare, making this approach unlikely.

Costimulatory blockade focuses on the T-cellrequirement of multiple signals prior to antigen-stimulated proliferation. Several of these receptorsand ligands have been defined, including CD28 andB7, and CD40 and CD154 molecules [49, 50]. Byblocking the secondary signals using monoclonal an-tibodies, a long-lasting immune downregulation oc-curs with specificity to the bound antigen. In thelaboratory, Elster et al. have shown prolonged al-logeneic skin graft acceptance in primates utilizinganti-CD154 monoclonal antibodies [51]. This holdsmuch promise in the context of CTA, as skin gener-ally has been the most difficult component to man-age with respect to rejection. Anti-CD154 has notyet been experimented in a CTA model, and its po-tential toxicity of inducing hypercoagulability [52]remains to be clarified.

Donor-specific tolerance remains the Holy Grailin transplantology. In the laboratory, stable chimerashave been created in rodents, large animals, and pri-mates [53–55]. These protocols require a course of re-cipient preconditioning followed by immune recon-stitution using T-cell-depleted bone-marrow grafts.Once a stable chimera has been created, limb andorgan transplantations were possible without pro-longed immunosuppression. However, these con-ditioning regimens are not clinically practical dueto possible host toxicity of ablative conditioning,graft failure, GVHD, and the requirement of a wait-ing period for chimerism to develop prior to trans-plantation. Active research is ongoing in these ar-eas to bring tolerance induction closer to clinicalimplementation.

OTHER APPLICATIONS OF CTA

The successful human hand transplants irrevoca-bly marked the clinical reality of CTA. However,hand and limb transplants represent only a fractionof the clinical potential of CTA. In 1995, Anthonyet al. first successfully studied heterotopic laryngealtransplants in dogs [56]. The carotid artery and exter-nal jugular veins served as the unilateral blood sup-ply to the transplanted larynx, and the superior andrecurrent laryngeal nerves supplied the innervationvia microsurgical anastomoses. The animals receivedCsA, methylprednisolone, and mycophenolic acid.Laryngeal function and nerve conduction were eval-uated by fiberoptic laryngoscopy and electromyo-graphic studies. These animals were shown to remainrejection free for over 100 days postoperatively andnone of the animals needed a tracheostomy [56]. In1998, Birchall reported the first successful laryngealtransplant in a patient who suffered irreversible dam-age to his larynx in a motorcycle accident [45]. Therevascularized allograft consisted of the larynx, thy-roid, parathyroids, three tracheal rings, and 70% ofthe pharynx, and allowed the patient to speak for thefirst time in 19 years.

Many potential applications of CTA lie in the fieldof reconstructive and plastic surgery. Current meth-ods of microvascular reconstruction for large tis-sue defects fall short in recreating normal sensation,function, and appearance. For example, mandibu-lar reconstruction, performed using a variety of os-teocutaneous flaps, such as radial forearm, fibula,and scapula, provides immediate coverage of theanatomic defect [57–59]. However, they may re-quire prosthetic implants, fail to replace the mus-cles necessary for mastication, and often are insen-sate. Though an aesthetic improvement, these recon-structions are not ideal, lacking the specialized motorand sensory functions of the face. These cases maybe better served by CTA. Successful surgical modelshave already been developed, including CTA of themandible in rabbits and monkeys [8, 9], and a hemi-maxillary nose module and ear-calvarium units in therabbit [60, 61]. In orthopedics, whole joint allograftsare technically feasible and have been performedclinically in humans [62], though the problem of

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lifelong immunosuppression and its associated risksremain.

THE FUTURE OF CTA AND THERECONSTRUCTIVE TRANSPLANT

SURGEON

As with any developing field, new technology re-quires new expertise and organization to move theadvancements forward. Multidisciplinary collabora-tion is essential to successful application of CTA, andthe components include the proper facility, an in-tegrated preoperative and postoperative patient careteam, and physicians trained in performing and man-aging CTAs.

At this early period of development, it is essen-tial to direct potential CTA patients to specializedcenters, which benefits the patient with the mostexperienced care and facilitates data collection forscientific analyses. In order to accommodate recon-structive challenges of the head and neck, face, upperand lower extremities, the future reconstructive trans-plant surgery is likely to evolve into its own specialty,possibly with training from dedicated fellowships.

Because the CTA center may not be near the pa-tient’s home, follow up of the graft by a physician isan issue. CTA surveillance requires familiarity withthe neurologic, dermatologic, vascular, and systemicmanifestations of rejection and immunosuppression.Currently, the operating surgeon oversees the man-agement of a CTA with consultants from multipledisciplines. However, this situation is evolving froma research environment and does not address theultimate needs in the discipline when the patientbase expands and CTA becomes common clinicalpractice.

CONCLUSION

Advances in research and successful clinical ap-plications of CTA made great strides to ensure itsplace in the future of transplant surgery. Unlike SOT,which in most cases is lifesaving, CTA provides thepossibility to improve the quality of life. These po-tential benefits need to be balanced with potentiallytoxic immunosuppression. Another concern is the

ability to regain satisfactory function; otherwise, itmay cause additional morbidities to the recipient asa useless limb. Thus far, both French and Americanteams have demonstrated successful functional re-covery while maintaining well-tolerated immunosup-pressive protocols. CTA will be a valuable addition tothe armamentarium of reconstructive surgeons to po-tentially and dramatically improve the lives of peoplewho are otherwise disfigured and/or crippled. Addi-tional work is ongoing to improve immunosuppres-sion, induce tolerance, and develop long-term pa-tient care management. In the near future, CTA mayultimately become as commonly practiced as solidorgan transplantation.

REFERENCES1. Reverdin JL. De la greffe epidmerque. Arch Gen Med.

1872;19:276.2. Masson JC. Skin grafting. JAMA. 1918;70:1581–1584.3. Gibson T, Medawar PB. Fate of skin homografts in man.

J Anat. 1943;77:299–310.4. Medawar PB. The behavior and fate of skin autografts

and skin homografts in rabbits. J Anat. 1944;78:176–199.

5. Murray JE. Organ transplantation (skin, kidney, heart) andthe plastic surgeon. Plast Reconstr Surg. 1971;47:425–431.

6. Schwind JF. Successful transplantation of a leg in albinorats with reestablishment of muscular control. Science.1936;84:355–358.

7. Lapchinsky AG, Eingorn AG, Uratkov EF. Homotransplan-tation of extremities in tolerant dogs observed up to sevenyears. Transplant Proc. 1973;5:773–779.

8. Randzio J, Kniha H, Gold ME, et al. Growth of vascularizedcomposite mandibular allografts in young rabbits. AnnPlast Surg. 1991;26(2):140–148.

9. Gold ME, Randzio J, Kniha H, et al. Transplantation ofvascularized composite mandibular allografts in youngcynomolgus monkeys. Ann Plast Surg. 1991;26(2):125–132.

10. Strome S, Sloman-Moll E, Samonte B, Wu J, Strome M. Arat model for a vascularized laryngeal allograft. Ann OtolRhinol Laryngol. 1992;101:950–953.

11. Lee WP, Rubin JP, Cober S, Ierino F, Randolph MA, SachsDH. Use of swine model in transplantation of vascularizedskeletal tissue allografts. Transplant Proc. 1998;30:2743–2745.

12. Egerszegi EP, Samulack DD, Daniel RK. Experimental mod-els in primates for reconstructive surgery utilizing tissuetransplants. Ann Plast Surg. 1984;13:423–430.

13. Poole M, Bowen JE, Batchelor JR. Prolong survival of ratleg allografts due to immunological enhancement. Trans-plantation. 1976;22:108–111.

COMPOSITE TISSUE ALLOTRANSPLANTATION 199

J J y

Invited Review

14. Black KS, Hewitt CW, Woodard TL, et al. Efforts to en-hance survival of limb allografts by prior administrationof whole blood in rats using a new survival end-point. JMicrosurg. 1982;3:162–167.

15. Lee WP, Randolph MA, Weiland AJ, Yaremchuk MJ. Pro-longed survival of vascularized limb tissue allografts bydonor irradiation. J Surg Res. 1995;59:578–588.

16. Lee WP, Yaremchuk MJ, Pan YC, Randolph MA, TanCM, Weiland AJ. Relative antigenicity of componentsof a vascularized limb allograft. Plast Reconstr Surg.1991;87:401–411.

17. Doi K. Homotransplantation of limbs in rats. A pre-liminary report on an experimental study with non-specific immunosuppressive drugs. Plast Reconstr Surg.1979;64:613–621.

18. Borel JF, Fleurer C, Gubler HU, Stahelin H. Biological effectsof cyclosporin A: A new antilymphocytic agent. AgentActions. 1976;6:468–475.

19. Ho S, Clipstone N, Timmermann L, et al. The mecha-nism of action of cyclosporin A and FK506. Clin Immunol.1996;80(3 Pt 2):S40–45.

20. Black KS, Hewitt CW, Fraser LA, et al. Cosmas and Damianin the Laboratory. N Engl J Med. 1982;306(6):368–369.

21. Hewitt CW, Black KS, Fraser LA, et al. Cyclosporine-A(CsA) is superior to prior donor-specific blood (DSB) trans-fusion for the extensive prolongation of rat limb allograftsurvival. Transplant Proc. 1983;15:514–517.

22. Furnas DW, Black KS, Hewitt CW, et al. Cyclosporin andlong-term survival of composite tissue allografts (limbtransplants) in rats with historical notes on the role ofplastic surgeons in allotransplantation. Transplant Proc.1983;15(4S1):3063–3068.

23. Hewitt CW, Black KS, Fraser LA, et al. Composite tis-sue (limb) allografts in rats I. Dose-dependent increase insurvival with cyclosporine. Transplantation. 1985;39:360–364.

24. Black KS, Hewitt CW, Fraser LA, et al. Composite tissue(limb) allografts in rats: II Indefinite survival using low dosecyclosporine. Transplantation. 1985;39:365–368.

25. Hovius SE, Stevens HP, van Nierop PW, Rating W, van StrikR, van der Meulen JC. Allogeneic transplantation of theradial side of the hand in the rhesus monkey: I. Technicalaspects. Plast Reconstr Surg. 1992;89(4):700–709.

26. Benhaim P, Anthony JP, Lin LY, McCalmont TH, MathesSJ. A long-term study of allogeneic rat hindlimb trans-plants immunosuppressed with RS-61443. Transplanta-tion. 1993;56:911–917.

27. Benhaim P, Anthony JP, Ferreira L, Borsanyi JP, MathesSJ. Use of combination of low-dose cyclosporin and RS-61443 in a rat hindlimb model of composite tissue allo-transplantation. Transplantation. 1996;61:527–532.

28. Liu J, Farmer JJ, Lane WS, Friedman J, WeissmanI, Schreiber SL. Calcineurin is a common target ofcyclophylin-cyclosporin A and FKBP-FK506 complexes.Cell. 1994;5:807–815.

29. Buttemeyer R, Jones NF, Min Z, Rao U. Rejection of thecomponent tissues of limb allografts in rats immunosup-pressed with FK506 and cyclosporin. Plast Reconstr Surg.1996;97(1):139–148.

30. Kahan BD, Podbielski J, Napoli KL, Katz SM, Meier-Kriesche HU, Van Buren CT. Immunosuppressive ef-fects and safety of a sirolimus/cyclosporine combina-tion regimen for renal transplantation. Transplantation.1998;66(8):1040–1046.

31. Nowygrod R, Appel G, Hardy MA. Use of ATG forreversal of acute allograft rejection. Transplant Proc.1981;13(1):469–472.

32. Ustuner ET, Majzoub RK, Ren X, et al. Swine compositetissue allotransplant model for preclinical hand transplantstudies. Microsurgery. 2000;20(8):400–406.

33. Jones JW, Gruber SA, Barker JH, Breidenbach WC. Suc-cessful hand transplantation—One-year follow-up. N EnglJ Med. 2000;343(7):468–473.

34. Francois CG, Breidenbach WC, Maldonado C, et al.First four human hand transplants. Microsurgery.2000;20(8):360–371.

35. Mackinnon SE, Hudson AR, Bain JR, Falk RE, Hunter DA.The peripheral nerve allograft: An assessment of regener-ation in the immunosuppressed host. Plast Reconstr Surg.1987;79(3):436–446.

36. Mackinnon SE, Hudson AR. Clinical application ofperipheral nerve transplantation. Plast Reconstr Surg.1992;90(4):695–699.

37. Yazdi B, Patel MP, Ramsamooj R, et al. Vascularized bonemarrow transplantation (VBMT): Induction of stable T cellchimerism and transplantation tolerance in unmodifiedrecipients. Transplant Proc. 1991;23(1):739–740.

38. Suzuki H, Patel N, Matthews M, DelRossi AJ, Doolin EJ,Hewitt CW. Vascularized bone marrow transplantation: Anew surgical approach using isolated bone/bone marrow.J Surg Res. 2000;89:176–183.

39. Janczewska S, Ziolkowska A, Durlik M, Olszewski WL,Lukomska B. Fast lymphoid reconstitution after vascular-ized bone marrow transplantation in lethally irradiatedrats. Transplantation. 1999;68(2):201–209.

40. Hewitt CW, Ramsamooj R, Patel MP, Yazdi B, Achauer BM,Black KS. Development of stable mixed T cell chimerismand transplantation tolerance without immune modula-tion in recipients of vascularized bone marrow allografts.Transplantation. 1990;50(5):766–772.

41. Durlik M, Lukomska B, Religa R, et al. Tolerance in-duction following allogeneic vascularized bone marrowtransplantation—The possible role of microchimerism.Transpl Int. 1998;11(S1):S299–302.

42. Barker JH, Jones JW, Breidenback WC. Closing remarks.International symposium on composite tissue transplan-tation. Transplant Proc. 1998;30:2787.

43. Dubernard J, Owen E, Herzberg G, et al. Human hand allo-graft: Report on first 6 months. Lancet. 1999;353:1315–1320.

44. Jones JW, Gruber SA, Barker JH, Breidenbach WC. Suc-cessful hand transplantation: Year follow-up. N Engl JMed. 2000;343:468–473.

45. Birchall M. Human laryngeal allograft: Shift of emphasisin transplantation. Lancet. 1998;351(9102):539–540.

46. Hofmann GO, Kirschner MH, Wagner FD, Brauns L,Gonschorek O, Buhren V. Allogeneic vascularized trans-plantation of human femoral diaphyses and total

200 C. TAI ET AL.

J J y

Invited Review

knee joints—First clinical experiences. Transplant Proc.1998;30(6):2754–2561.

47. Hofmann GO, Kirschner MH, Wagner FD, Land W,Buhren V. Allogeneic vascularized grafting of human kneejoints with postoperative immunosuppression. Arch OrthoTrauma Surg. 1997;116(3):125–128.

48. Lee WP, Rubin JP, Bourget JL, et al. Tolerance to limbtissue allografts between swine matched for major his-tocompatibility complex antigens. Plast Reconstr Surg.2001;107(6):1482–1490.

49. June CH, Bluestone JA, Nadler LM, Thompson CB.The B7 and CD28 receptor families. Immunol Today.1994;15:321–331.

50. Grewal IS, Flavell RA. CD40 and CD154 in cell-mediatedimmunity. Annu Rev Immunol. 1998;15:111–135.

51. Elster EA, Xu H, Burkly LC, et al. Primary skin graft accep-tance with anti-CD154 in a non-human primate skin graftmodel (abstract). Transplantation. 2000;69:S239.

52. Kawai T, Andrews D, Covin RB, Sachs DH, Cosimi AB. In-creased incidence of thromboembolic complications fol-lowing anti-CD40L monoclonal antibody treatment incynomolgus monkeys (letter to the editor). Nature Med.2000;6:114.

53. Foster RD, Fan L, Niepp M, et al. Donor-specific toler-ance induction in composite tissue allografts. Am J Surg.1998;176:418–421.

54. Fuchimoto Y, Huang CA, Yamada K, et al. Mixedchimerism and tolerance without whole body irradiationin a large animal model. J Clin Invest. 2000;105:1779–1789.

55. Kawai T, Cosimi AB, Colvin RB, et al. Mixed allogeneicchimersim and renal allograft tolerance in cynomolgusmonkeys. Transplantation. 1995;59:256–262.

56. Anthony JP, Allen DB, Trabulsy PP, Mahdavian M, MathesSJ. Canine laryngeal transplantation: Preliminary studiesand a new heterotopic allotransplantation model. EurArch Otorhinolaryngol. 1995;252(4):197–205.

57. Soutar DS, Widdowson WP. Immediate reconstruction ofthe mandible using a vascularized segment of radius.Head Neck. 1986;8:232–246.

58. Swartz WM, Banis JC, Newton ED, Ramasastry SS, JonesNF, Acland R. The osteocutaneous scapular flap formandibular and maxillary reconstruction. Plast ReconstrSurg. 1986;77:530–545.

59. Hidalgo DA. Fibular free flap: A new method of mandiblereconstruction. Plast Reconstr Surg. 1989;84(1):71–79.

60. Kniha H, Randzio J, Furnas DW. Results after allo-genic grafting of hemimaxillary nose modules in animalexperiments under cyclosporin A immunosuppression.Deutsche Z Mund- Kiefer- Gesichts-Chir. 1989;13(5):386–390.

61. Kniha H, Randzio J, Permanetter W, Furnas DW. Allo-geneic transplantation of ear-calvarium units in the rabbitanimal experiment with immunosuppressive protection bycyclosporin A. Fortschr Kiefer- Gesichts-Chir. 1990;35:28–30.

62. Hofmann GO, Kirschner MH. Clinical experience in allo-geneic vascularized bone and joint allografting. Micro-surgery. 2000;20(8):375–383.

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