Ulnar shortening: results for treatment of distal radioulnar joint pathology and conversion to DRUJ replacement arthroplasty.

BACKGROUND: Ulnar shortening (US) is used for treatment of ulnar abutment, early osteoarthrosis (OA) and distal radioulnar joint (DRUJ) instability. However, it has never been strongly advocated as a mid-stage procedure to slow OA progression and reduce requirement of secondary DRUJ procedures. The study aim was to determine if a specific sigmoid notch type is likely to lead to DRUJ replacement after US. METHODS: A retrospective study of 119 patients (124 wrists) with DRUJ painful early osteoarthritis, ulnar abutment and DRUJ instability that underwent US was performed. The goals of osteotomy were to decrease pain and slow the initiation or progression of OA. Sigmoid notch type, previous trauma, bone healing time, pain relief, ulnar variance and conversion to DRUJ arthroplasty were analyzed. RESULTS: Of the 124 wrists studied, bone healing took 3.33 months of average (union rate 98.3%). Sigmoid notch type distribution was 55.6% for type 1, 25.8% for type 2, and 18.5% for type 3. Of the patients with pain after US, 37 had hardware removal and 13 required a DRUJ semi-constrained arthroplasty. Even though analysis did not show any statistically significant correlation, a slight trend towards association of sigmoid notch type 3 with conversion to DRUJ arthroplasty was found. CONCLUSION: US has a role in treatment of DRUJ pathology, and its use may delay the need for DRUJ secondary procedures, protecting the native joint. A specific sigmoid notch type does not present risk for OA and does not appear to be related to conversion to DRUJ arthroplasty. Type of study: Therapeutic.

ANTECEDENTES: El acortamiento cubital es utilizado para el tratamiento del síndrome de impactación, osteoartrosis (OA) temprana y la inestabilidad de la articulación radiocubital distal (ARCD). Sin embargo, no se ha recomendado como procedimiento intermedio para detener la progresión de la OA y reducir la necesidad de procedimientos secundarios. El objetivo es determinar si un tipo específico de la escotadura sigmoidea predispone a una artroplastia de la ARCD después del acortamiento cubital. MÉTODOS: Estudio retrospectivo de 119 pacientes (124 muñecas) a las que se les realizó acortamiento cubital. El objetivo de la osteotomía fue disminuir el dolor y retardar el progreso de la OA. Se analizó el tipo de escotadura sigmoidea, trauma previo, tiempo de consolidación ósea, alivio del dolor, varianza cubital y conversión a artroplastia. RESULTADOS: De las 124 muñecas estudiadas, la consolidación ocurrió en 3.33 meses en promedio (98.3% de consolidación). El tipo de escotadura sigmoidea fue 55.6% tipo 1; 25.8% tipo 2 y 18.5% tipo 3, 37 pacientes ameritaron retiro de material y 13 una artroplastia de la ARCD semiconstriñida. Aunque el análisis no mostró ninguna correlación estadísticamente significativa, una tendencia leve hacia la Asociación del tipo 3 de la escotadura sigmoidea con la conversión a la artroplastia de ARCD fue encontrada. CONCLUSIONES: El acortamiento cubital juega un papel en el tratamiento de la patología de la ARCD, su uso puede retrasar la necesidad de procedimientos secundarios. Un tipo de escotadura sigmoidea específica no presenta riesgo para la OA y no parece estar relacionado con la conversión a la artroplastia de la ARCD.

Graft vasculopathy in clinical hand transplantation.

Allogeneic hand transplantation is now a clinical reality. While results have been encouraging, acute rejection rates are higher than in their solid-organ counterparts. In contrast, chronic rejections, as defined by vasculopathy and/or fibrosis and atrophy of skin and other tissues, as well as antibody mediated rejection, have not been reported in a compliant hand transplant recipient. Monitoring vascularized composite allograft (VCA) hand recipients for rejection has routinely involved punch skin biopsies, vascular imaging and graft appearance. Our program, which has transplanted a total of 6 hand recipients, has experience which challenges these precepts. We present evidence that the vessels, both arteries and veins may also be a primary target of rejection in the hand. Two of our recipients developed severe intimal hyperplasia and vasculopathy early post-transplant. An analysis of events and our four other patients has shown that the standard techniques used for surveillance of rejection (i.e. punch skin biopsies, DSA and conventional vascular imaging studies) are inadequate for detecting the early stages of vasculopathy. In response, we have initiated studies using ultrasound biomicroscopy (UBM) to evaluate the vessel wall thickness. These findings suggest that vasculopathy should be a focus of frequent monitoring in VCA of the hand.

Atypical acute rejection after hand transplantation.

Skin rejection after hand transplantation is characterized by a maculopapular erythematous rash that may be diffuse, patchy or focal, and distributed over forearms and dorsum of the hands. This 'classical' pattern of rejection usually spares the skin of the palm and does not affect the nails. Herein, we report the experience on four cases presenting with an 'atypical' pattern of rejection that is novel in involving the palmar skin and the nails. All patients were young and exposed to repetitive and persistent mechanical stress of the palm. Characteristic features of rejection included a desquamative rash associated with dry skin, red papules, scaling and lichenification localized to the palm. Skin lesions were associated with nail dystrophy, degeneration, deformation or loss. Histology of the skin and nail bed revealed a lymphocytic infiltrate with predominance of T cells (CD3+, CD4+ and CD8+), with small numbers of B cells (CD20+ and CD79a+) and a low number of Forkhead transcription factor 3 (FOXP3)-positive cells in one patient. The lesions persisted over weeks to months, responded poorly to steroid treatment and were managed with antithymocyte globulin (ATG; Thymoglobulin, Genzyme, Cambridge, MA), alemtuzumab and/or intensified maintenance immunosuppression.

Leukodystrophy and bone marrow transplantation: role of mixed hematopoietic chimerism.

Bone Marrow Transplantation (BMT) is currently the most physiologic treatment for some types of leukodystrophies. In enzyme deficiency states, replacement of defective genes with cells carrying "normal" copies of these genes offers a natural form of gene therapy. This review will cover the various disease states which may be treated using bone marrow transplantation as well as the obstacles and advantages offered by this treatment modality. The potential for mixed hematopoietic chimerism, with reference to the advantages and disadvantages of treating various leukodystrophies, is reviewed. Finally, certain approaches which would reduce the morbidity and mortality associated with conventional BMT are discussed. If these obstacles can be overcome, BMT may offer the hope of cure to a number, but certainly not all, leukodystrophies.

Patterns of hemopoietic reconstitution in nonobese diabetic mice: dichotomy of allogeneic resistance versus competitive advantage of disease-resistant marrow.

Complete replacement of the immune system via allogeneic bone marrow transplantation is sufficient to prevent diabetes in the nonobese diabetic (NOD) mouse model. In the present study we examined whether mixed allogeneic reconstitution would be sufficient to interrupt the autoimmune process with respect to occurrence of overt diabetes, as well as preexisting autoimmune insulitis. NOD mice were lethally irradiated and reconstituted with a mixture of NOD and B10.BR marrow. A relative resistance to allogeneic bone marrow engraftment was noted in NOD recipients of the mixed bone marrow inoculum, compared with disease-resistant controls. Moreover, unlike disease-resistant controls, all animals that initially repopulated as mixed donor/host chimeras became predominantly allogeneic by 4 mo, suggesting a competitive advantage for long term engraftment for disease-resistant marrow. All but one mouse in the group that engrafted with allogeneic marrow remained free of diabetes for the entire follow-up period (n = 22). Moreover, in all animals examined, virtually all islets were free of insulitis. In contrast, 74% of NOD mice that received similar conditioning and failed to engraft with donor marrow developed acute diabetes and intra-islet insulitis was present in all animals examined. These data suggest that NOD mice exhibit a relative resistance to engraftment compared with disease-resistant recipients. Conversely, animals that initially repopulated as a mixture of syngeneic and donor marrow become converted to virtually all donor by 4 mo. These data provide additional support that a defective stem cell is responsible for autoimmune diabetes in this experimental model.

Facilitating cells enable engraftment of purified fetal liver stem cells in allogeneic recipients.

It has been reported that while stem cells purified from adult bone marrow engraft in syngeneic recipients, they fail to engraft in allogeneic recipients. We have recently shown that the addition of as few as 30,000 facilitating cells (CD8+/CD3+/CD45R+/Thy 1.2+/TCR-), a unique bone marrow-derived population that does not possess stem cell properties, results in the permanent engraftment of stem cells in a major histocompatibility complex (MHC)-disparate allogeneic host. It has been suggested that fetal hematopoietic tissue may be a source of stem cells with enhanced proliferative and self-renewal properties compared with adult bone marrow. We were interested, therefore, in whether fetal stem cells demonstrated a superior capacity to engraft in allogeneic recipients. In this study, we have examined the engraftment properties of mouse fetal liver cells in syngeneic and allogeneic recipients. Transplantation of unmodified fetal liver cells into allogeneic recipients results in stable multilineage chimerism with donor-specific tolerance, indicating that the pluripotent hematopoietic stem cell is present in fetal liver and is capable of engraftment in allogeneic adult recipients. Similarly, 2000 to 3000 sorted fetal liver stem cells (Sca+/c-kit+/Lin-) successfully reconstituted lethally irradiated syngeneic adults and adults differing only in minor histocompatibility antigens. Two thousand to 10,000 fetal stem cells failed to rescue lethally irradiated allogeneic recipients, but the addition of 30,000 MHC-matched purified facilitating cells to the fetal stem cell inoculum resulted in sustained engraftment with multilineage production. These results, which parallel our earlier work with stem cells derived from adult bone marrow, indicate that the pluripotent fetal stem cell behaves in a fashion similar to that of adult stem cells with regard to allogeneic transplantation.

Mixed allogeneic chimerism induced by a sublethal approach prevents autoimmune diabetes and reverses insulitis in nonobese diabetic (NOD) mice.

Evidence in experimental models suggests that many autoimmune diseases can be prevented by transplantation of bone marrow from disease-resistant donors. For potential clinical application, it would be important to avoid the morbidity and mortality associated with lethal conditioning and achieve mixed chimerism using less than complete recipient ablation. We report here for the first time that stable chimerism achieved in NOD mice using a sublethal radiation-based conditioning approach is sufficient to prevent beta-cell destruction and abrogate insulitis in prediabetic NOD mice. The percentage of NOD mouse recipients (8 wk of age) that engrafted with donor bone marrow correlated with the dose of irradiation and number of bone marrow cells transplanted. Engraftment of B10.BR bone marrow occurred in > or = 94% of animals receiving > or = 750 cGy of total body irradiation before bone marrow transplantation and > or = 30 x 10(6) bone marrow cells, while reproducible engraftment did not occur at radiation doses of less than 700 cGy and cellular doses of less than 30 x 10(6) bone marrow cells. All chimeric animals remained free of diabetes (n = 38) for 10 mo following bone marrow transplantation. Moreover, in all animals examined, no insulitis was present from 12 to 36 wk following reconstitution. In striking contrast, 61% (22 of 36) of NOD recipients that were conditioned but did not receive bone marrow developed acute diabetes by 12 mo. Insulitis was present in all remaining animals. These results suggest that allogeneic chimerism achieved using a sublethal conditioning approach can prevent the onset of diabetes and even reverse preexisting insulitis in NOD mice.

Allogeneic chimerism induces donor-specific tolerance to simultaneous islet allografts in nonobese diabetic mice.

BACKGROUND: Nonobese diabetic (NOD) mice develop a systemic autoimmune disease that resembles type I diabetes in human beings. Previous studies in NOD mice have shown that transplantation of bone marrow from normal donors to lethally conditioned recipients prevented the development of diabetes (B10.BR-->NOD, BALB/c-->NOD). The focus of the present study was to examine whether donor-specific transplantation tolerance for islet allografts could be achieved if islet transplantations were performed coincident with the time of bone marrow infusion in diabetic NOD mice. Moreover, the transplanted islets were evaluated for evidence of recurrent autoimmunity. METHODS: Female NOD mice were followed until autoimmune diabetes occurred (urine glucose, to +; blood glucose level, 300 mg/dl or greater). Diabetic NOD mice were irradiated with 950 cGy total body irradiation and received 30 x 10(6) untreated B10.BR bone marrow cells (B10.BR-->NOD). A simultaneous islet allograft was placed under the renal capsule within 24 hours after infusion of the bone marrow cells. Mice were monitored by means of blood glucose levels, and histologic analyses were performed on the transplanted islet. RESULTS: Islet allografts genetically matched to the bone marrow donor were significantly prolonged (n = 5; mean survival time, 206 days or more) and showed no evidence for chronic rejection or recurrent insulitis, whereas major histocompatibility complex-disparate third-party allografts were rejected (n = 3; mean survival time, 37 days) and exhibited lymphocytic infiltration compatible with rejection on histologic evaluation. CONCLUSIONS: These data suggest that permanent donor-specific tolerance to islet allografts placed simultaneously with bone marrow transplantation can be achieved in diabetic NOD mice. Moreover, recurrent autoimmune destruction of the pancreatic tissue is prevented by the bone marrow chimerism.

A minimal conditioning approach to achieve stable multilineage mouse plus rat chimerism.

Transplantation of untreated rat bone marrow into lethally irradiated (950 cGy) mouse recipients results in durable xenogeneic (rat-->mouse) chimerism and confers donor-specific transplantation tolerance for subsequent xenografts. The purpose of the present study was to characterize the minimal dose of total body irradiation (TBI) which would allow engraftment of rat bone marrow in mouse recipients. We report here that durable and stable lymphohaematopoietic cross-species chimerism can be achieved using a less than totally ablative radiation-based conditioning approach. The percentage of B10 mouse recipients which engrafted with rat bone marrow cells correlated with the dose of TBI. Engraftment of rat bone marrow stem cells occurred in all animals receiving 750 cGy prior to bone marrow transplantation, while no engraftment was detected at doses less than 650 cGy. Although most of the recipients were repopulated with mixed mouse and rat multilineage chimerism, some exhibited a predominance of rat cells. Although mixed xenogeneic rat/mouse chimeras prepared by lethal TBI produced only mouse derived RBC (red blood cells), chimeras prepared by sublethal conditioning produced both rat and mouse RBC. Only animals with detectable chimerism exhibited specific functional transplantation tolerance to donor xenoantigens, as assessed in vitro by mixed lymphocyte reaction assay. This model may offer an in vivo approach to study the role of species-specific growth factors in stem cell biology as well as the mechanisms for the induction of tolerance across species barriers.

Xenotransplantation.

Transplantation of organs across a species barrier has long been a dream of the transplantation community. Renewed interest in xenotransplantation has emerged due to the short supply of organs available for clinical transplantation. However, transplantation of solid organs across a species barrier has not matched the success of allogeneic combinations, even for closely related species. The rejection response to xenografts is vigorous and not adequately controlled by conventional immunosuppressive agents that control alloreactivity. This may suggest a different mechanism for xenoreactivity, or stronger histocompatibility antigen disparities. This article reviews the current clinical experience with xenografts, mechanisms of xenoreactivity, the induction of tolerance across species disparities, and recent models in which human tissue has been transplanted into other species as an in vivo model of the human immune system.

Characterization and comparison of the lytic function of NKR-P1+ and NKR-P1-rat natural killer cell clones established from NKR-P1bright/TCR alpha beta-cell lines.

From sorted rat NKR-P1bright/T cell receptor (TCR) alpha beta-cells, we established interleukin (IL)-2-dependent cell lines with the morphology, phenotype and function of natural killer (NK) cells. The cell lines NKbr11.3 and NKbr1.28 had large-granular-lymphocyte morphology, were capable of lysing NK-and lymphokine-activated-killer-susceptible target cells, and had the phenotype NKR-P1bright/CD3-/CD4-/CD5-/CD25-/gp42+/TCR alpha beta-. Both cell lines mediated reverse antibody-dependent cellular cytotoxicity via NKR-P1. NKR-P1-subpopulations, identical in all other aspects of phenotype, spontaneously developed in both cell lines. Cloning of NKbr11.3 and NKbr1.28 by limiting dilution resulted in two NKR-P1+ clones, 11.3(6B) and 1.28(3D), and three NKR-P1- clones, 11.3(8A), 11.3(10B), and 1.28(9F). The NKR-P1- clones were lytic and their target preference resembled that of the parental lines, except that C1498 and P815 appeared to be poor targets for 11.3(8A) and 11.3(10B). These cells represent the first reported rat IL-2-dependent NK cell lines and clones. They will be useful for the study of NK cell function as well as the function and expression of NKR-P1.

Phenotypic characterization of a novel bone marrow-derived cell that facilitates engraftment of allogeneic bone marrow stem cells.

Bone marrow transplantation is an accepted therapy for hematologic malignancies, aplastic anemia, metabolic disorders, and solid tumors. However, graft-versus-host disease (GVHD) and failure of engraftment have limited the widespread application of this technology to nonmalignant disease states. The use of purified bone marrow stem cells has been suggested as an approach to promote engraftment yet avoid GVHD. Although bone marrow stem cells, purified by cell sorting, engraft and repopulate lethally irradiated genetically identical recipients, they do not engraft in major histocompatibility complex (MHC)-disparate allogeneic recipients. We report for the first time the characterization of a novel cell population of donor bone marrow origin, separate from the hematopoietic stem cell, that facilitates engraftment of purified allogeneic bone marrow stem cells in an MHC-specific fashion without causing GVHD. Although 1,000 purified stem cells (c-kit+/Sca-1+/lineage-) reliably repopulate syngeneic mouse recipients, 10 times that number do not engraft in MHC-disparate allogeneic recipients. The addition of as few as 30,000 facilitating cells (CD8+/CD45R+/TCR-) is sufficient to permit engraftment of purified stem cells in MHC-disparate recipients. The cell surface phenotype of this purified cellular population differs significantly from other characterized lineages of lymphoid or myeloid origin. Based on multiparameter rare-events cell sorting, the facilitating fraction is CD8+, CD3+, CD45R+, Thy 1+, class IIdim/intermediate but alpha beta-TCR- and gamma delta-TCR-. This cellular population comprises approximately 0.4% of the total bone marrow and is separate from the hematopoietic stem cell. The coadministration of purified facilitating cells plus stem cells to optimize engraftment yet avoid GVHD may expand the potential application of bone marrow transplantation to disease states in which the morbidity and mortality associated with conventional BMT cannot be justified.

Mixed xenogeneic chimerism (mouse+rat-->mouse) to induce donor-specific tolerance to sequential or simultaneous islet xenografts.

We previously reported that donor-specific rat islet xenografts were accepted by fully xenogeneic (rat-->mouse) chimeras when the islets were transplanted at least six weeks following reconstitution. The purpose of the present study was to examine whether a similar outcome would occur for mixed xenogeneic (mouse+rat-->mouse) chimeras if the islets were placed coincident with the time of bone marrow infusion. As with fully xenogeneic chimeras (rat-->mouse), synchronous donor-specific F344 rat (Rt1A1) islet xenografts were significantly prolonged (MST > 139 days) in mixed xenogeneic (mouse+rat-->mouse) chimeras, while MHC-disparate third-party WF rat (Rt1Au) grafts were rejected (MST = 21.2 days). The transplanted donor-specific islets were functional to maintain euglycemia and they were regulated in function to respond to a glucose challenge. For potential clinical application, it would be of obvious benefit if the islet xenografts could be placed at the time of bone marrow transplantation. We therefore performed similar studies using donor islets administered simultaneously with bone marrow. Donor-specific islet xenografts were permanently accepted by all mouse recipients (n = 5). When MHC-disparate third-party rat islets were transplanted, only 3 of 8 islet xenografts were rejected; the other 5 remained functional from 77 to 90 days posttransplantation. Although prolonged and functional, the MHC-disparate islets that were accepted exhibited histologic evidence of fibrosis and rejection, while those matched to the donor did not. These data therefore suggest that donor-specific islet xenografts are permanently accepted if placed simultaneously or sequentially following mixed xenogeneic bone marrow reconstitution.

Characterization and function of the NKR-P1dim/T cell receptor-alpha beta+ subset of rat T cells.

MHC-unrestricted cytotoxicity is mediated primarily by NK cells. However, some subsets of TCR-alpha beta+ and TCR-gamma delta+ T cells also have the capacity to mediate MHC-unrestricted cytotoxicity, particularly after incubation in high concentrations of IL-2. Currently, it is not known what receptors on T cells are responsible for this activity, nor whether such receptors are the same as those on NK cells. We have recently described a type II integral membrane protein, termed NKR-P1, that is expressed at high levels on rat NK cells (NKR-P1bright). NKR-P1 contains a carbohydrate recognition domain characteristic of C-type (Ca(2+)-dependent) animal lectins and is a representative member of a distinct group of this superfamily. By a variety of criteria, NKR-P1 is linked to a signaling pathway that activates NK cell lytic function. Based on its structure and function, NKR-P1 has been implicated as a candidate molecule involved in or contributing to MHC-unrestricted cytotoxicity. We describe herein the expression of NKR-P1 at low levels on a small subset of rat T cells with an NKR-P1dim/TCR-alpha beta+ phenotype and on a small subset of cells with an NKR-P1dim/TCR-alpha beta- phenotype (presumably containing gamma delta+ T cells). Before incubation with IL-2, the NKR-P1dim subsets of cells lack MHC-unrestricted cytolytic capacity and lack the capacity for reverse antibody-dependent cellular cytotoxicity (rADCC) mediated via NKR-P1. However, culture of NKR-P1dim/TCR-alpha beta+ T cells in IL-2 led to the acquisition of both MHC-unrestricted cytotoxicity and the capacity for rADCC via NKR-P1. NK-like cytolytic function was not found among IL-2-activated NKR-P1-/TCR-alpha beta+ T cells. These data suggest that expression of functional NKR-P1 (i.e., ability to signal rADCC) correlates with and potentially contributes to MHC-unrestricted cytotoxicity.

Coexpression of NKR-P1 and alpha beta-TCR on lymphoid cells in fully xenogeneic (rat-->mouse) chimeras and syngeneically reconstituted (A-->A) rats.

We have identified three populations of cells among rat splenocytes expressing NKR-P1, including cells of NKR-P1bright/alpha beta-TCR-, NKR-P1dim/alpha beta-TCR+, and NKR-P1dim/alpha beta-TCR- phenotypes. To study the phenotypic characteristics and development of these various cell populations, we have made use of transplanting untreated rat bone marrow into recipient rats (syngeneic) or mice (fully xenogeneic) conditioned with total body irradiation. Rat NK cells exhibit normal phenotypic markers (NKR-P1+, CD8+) and are normally functional by 28 days after reconstitution. We have found that the various populations of NKR-P1+ cells are enriched significantly in the spleen and follow a characteristic pattern of development in the first mo after reconstitution. After syngeneic bone marrow reconstitution (rat-->rat), NKR-P1dim and NKR-P1bright cells (3-15%) can be demonstrated among splenocytes as early as day 3 after bone marrow transplantation. By day 7, the NKR-P1+ cells reach peak levels and comprise as much as 80% of splenic lymphoid cells, with 35% being NKR-P1bright and 45% being NKR-P1dim. The percentage of NKR-P1+ cells decreases over the next several wk until they constitute "normal rat" levels with 8 to 20% being NKR-P1bright and only 1 to 5% being NKR-P1dim. These same populations are also present in fully xenogeneic chimeras. In both models, approximately 80 to 90% of the NKR-P1dim cells were found to coexpress alpha beta-TCR at all time points. These NKR-P1dim/alpha beta-TCR+ cells are not large granular lymphocytes and lack NK cell lytic activity against YAC-1 target cells. Additional analyses of cells derived from spleen, bone marrow, and thymus indicated that NKR-P1+ cells develop, for the most part, in a thymic-independent manner in our fully xenogeneic chimeras and syngeneically reconstituted rats. At present the developmental pathway of these NKR-P1dim cells remains speculative.