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T R Spitzer

Publications and source records attributed to T R Spitzer.

At least 19 recordsLinked to original sources
PubMed2006

Myeloma responses and tolerance following combined kidney and nonmyeloablative marrow transplantation: in vivo and in vitro analyses.

Six patients with renal failure due to multiple myeloma (MM) received simultaneous kidney and bone marrow transplantation (BMT) from HLA-identical sibling donors following nonmyeloablative conditioning, including cyclophosphamide (CP), peritransplant antithymocyte globulin and thymic irradiation. Cyclosporine (CyA) was given for approximately 2 months posttransplant, followed by donor leukocyte infusions. All six patients accepted their kidney grafts long-term. Three patients lost detectable chimerism but accepted their kidney grafts off immunosuppression for 1.3 to >7 years. One such patient had strong antidonor cytotoxic T lymphocyte (CTL) responses in association with marrow rejection. Two patients achieved full donor chimerism, but resumed immunosuppression to treat graft-versus-host disease. Only one patient experienced rejection following CyA withdrawal. He responded to immunosuppression, which was later successfully withdrawn. The rejection episode was associated with antidonor Th reactivity. Patients showed CTL unresponsiveness to cultured donor renal tubular epithelial cells. Initially recovering T cells were memory cells and were enriched for CD4+CD25+ cells. Three patients are in sustained complete remissions of MM, despite loss of chimerism in two. Combined kidney/BMT with nonmyeloablative conditioning can achieve renal allograft tolerance and excellent myeloma responses, even in the presence of donor marrow rejection and antidonor alloresponses in vitro.

Adult↗
PubMed2002

High-dose carboplatin and regimen-related toxicity following autologous bone marrow transplant.

Pharmacokinetic analysis of carboplatin dosing suggests a more accurate prediction of toxicity when the dose is based on the area under the plasma concentration vs time curve (AUC) instead of body surface area (BSA). We retrospectively calculated the carboplatin AUC of 117 patients who received an autologous stem cell transplant following a conditioning regimen consisting of carboplatin 1800 mg/m(2) and cyclophosphamide 6000 mg/m(2) to identify whether higher carboplatin exposure resulted in an increase in regimen-related non-hematologic toxicities. The most common non-hematologic toxicities were gastrointestinal and hepatic. Twenty (17%) patients experienced additional > or =grade 2 toxicity, specifically, renal toxicity significantly associated with a higher median AUC of 10.2 mg/ml(-1) min (P = 0.001). Prior platinum therapy was also significantly associated with toxicity (P = 0.052). While carboplatin dose based on BSA varied minimally (median 990 (range 450-1340) mg, the calculated AUC showed a near four-fold range of exposure (median 7.8 (range 3.6 to 13.8) mg/ml(-1) min). These data suggest a relationship between non-hematologic adverse events and the estimated AUC. Prospective trials will be necessary to identify the target carboplatin AUC which optimizes outcome and minimizes toxicity in the autologous transplant setting.

Adolescent↗
PubMed2001

Successful pregnancy after high-dose cyclophosphamide, carboplatinum, and taxol with peripheral blood stem cell transplant in a young woman with ovarian carcinoma.

BACKGROUND: Both ovarian carcinoma and high-dose chemotherapy tend to preclude future pregnancies. CASE: We report a case of a young woman with borderline ovarian carcinoma and invasive tumor implants who underwent surgical debulking with preservation of future fertility followed by carboplatinum, paclitaxel (Taxol), and subsequent high-dose chemotherapy with subsequent peripheral blood stem cell rescue as part of a phase I clinical trial. After a brief period of amenorrhea, the patient had a successful pregnancy that was complicated by a spontaneous abortion in the first trimester. Several months later she conceived and delivered a healthy baby at term. CONCLUSIONS: To our knowledge this is the first reported case of pregnancy after high-dose chemotherapy with stem cell transplant in a woman with ovarian carcinoma.

Adult↗
PubMed2001

Engraftment syndrome following hematopoietic stem cell transplantation.

During neutrophil recovery following hematopoietic stem cell transplantation, a constellation of symptoms and signs including fever, erythrodermatous skin rash, and noncardiogenic pulmonary edema often occur. These clinical findings have usually been referred to as engraftment syndrome, or, reflecting the manifestations of increased capillary permeability, capillary leak syndrome. While described most often following autologous stem cell transplantation, a similar clinical syndrome has been observed followed allogeneic stem cell transplantation. Distinction from graft-versus-host disease in the allogeneic setting however, has been difficult. Recent experience with non-myeloablative conditioning for stem cell transplantation, however, reveals that an engraftment syndrome independent of GVHD may occur. In some cases, this engraftment syndrome may be a manifestation of a host-versus-graft reaction (graft rejection). While cellular and cytokine interactions are believed to be responsible for these clinical findings, a distinct effector cell population and cytokine profile have not been defined. Engraftment syndromes are likely associated with an increased transplant-related mortality, mostly from pulmonary and associated multi-organ failure. Corticosteroid therapy is often dramatically effective for engraftment syndrome, particularly for the treatment of the pulmonary manifestations. A proposal for a more uniform definition of engraftment syndrome has been developed in order to allow for a reproducible method of reporting of this complication and for evaluating prophylactic and therapeutic strategies.

Capillary Leak Syndrome↗
PubMed2001

Successful allogeneic stem cell transplantation with nonmyeloablative conditioning in patients with relapsed hematologic malignancy following autologous stem cell transplantation.

The use of myeloablative preparative therapy and allogeneic stem cell transplantation (alloSCT) as salvage therapy for adult patients with relapsed hematologic malignancy after autologous stem cell transplantation (autoSCT) is generally unsuccessful due to very high treatment-related mortality rates. We evaluated the outcome of HLA-matched related donor alloSCT following nonmyeloablative preparative therapy in 13 patients (median age, 38 years) with relapsed hematologic malignancies (Hodgkin's disease, n = 4; Hodgkin's disease and advanced myelodysplastic syndrome, n = 1; non-Hodgkin's lymphoma, n = 6; multiple myeloma, n = 2) after initial autoSCT. Median time from autoSCT to alloSCT was 12 months (range, 3-24 months); 6 patients had chemotherapy-refractory disease following autoSCT, 6 were in untreated relapse, and 1 had a partial response from salvage chemotherapy. Preparative therapy consisted of cyclophosphamide, 150-200 mg/kg; peritransplantation anti-thymocyte globulin; thymic irradiation (in patients who had not received previous mediastinal irradiation); and a very short course of cyclosporine as GVHD prophylaxis. All patients achieved initial mixed chimerism as defined by greater than 1% donor peripheral white blood cells. Seven patients, who had no evidence of GVHD, received prophylactic DLI beginning 5 to 6 weeks after transplantation for conversion of mixed chimerism to full donor hematopoiesis and to optimize a graft-versus-tumor effect. Six patients showed conversion to full donor chimerism and 1 lost the graft. Grade II or greater acute GVHD occurred in 9 patients. Seven patients achieved a complete response; 6 had no response. The median survival time of the 13 patients is currently 10 months (range, 3-39 months), with an overall survival probability at 2 years of 45% (95% confidence interval [CI], 19%-73%) and a disease-free survival probability at 2 years of 37.5% (95% CI, 12%-65%). Thus, this novel nonmyeloablative alloSCT strategy followed by prophylactic DLI was well tolerated and can result in durable disease-free survival among patients with advanced hematologic malignancies after a failed autoSCT. Further follow-up and evaluation of additional patients are required to conclusively establish the role of this strategy in the treatment of hematologic malignancies after an autologous transplantation.

Adult↗
PubMed2000

Cytokine-mobilized peripheral blood progenitor cells for allogeneic reconstitution of miniature swine.

BACKGROUND: Because of the relative ease of acquisition, increased yield, and improved engraftment characteristics, mobilized peripheral blood progenitor (stem) cells (PBSCs) have recently become the preferred source for hematopoietic stem cell transplantation. In our laboratory, procurement of a megadose of PBSCs is necessary for on-going studies evaluating non-myelosuppressive transplant regimens for the induction of mixed chimerism and allograft tolerance. To exploit hematopoietic growth factor synergy, we have sought to combine growth factors with proven utility to improve PBSC mobilization and maximize our PBSC procurement through an automated collection procedure. METHODS: Mobilization characteristics of PBSCs were determined in 2-5-month-old miniature swine. Animals received either swine recombinant stem cell factor (pSCF, 100 microg/kg) and swine recombinant interleukin 3 (pIL-3, 100 microg/kg), administered intramuscularly for 8 days, or pSCF, pIL-3, and human recombinant granulocyte-colony stimulating factor (hG-CSF), at 10 microg/kg. Leukapheresis was performed beginning on day 5 of cytokine treatment and continued daily for 3 days. RESULTS: Collection of PBSCs from cytokine-mobilized animals via an automated leukapheresis procedure demonstrated a 10-fold increase in the number of total nucleated cells (TNC) (20-30 x 10(10) TNC) compared to bone marrow harvesting (2-3 x 10(10) total TNC). A more rapid rise in white blood cells (WBCs) was seen after administration of all three cytokines compared to pSCF and pIL-3 alone. An increase in colony-forming unit granulocyte-macrophage frequency measured daily from peripheral blood during cytokine treatment, was seen with the addition of hG-CSF to pSCF/pIL-3 correlating well with the rise in WBCs. Similarly, the addition of hG-CSF demonstrated a notable increase in the median progenitor cell yield from the 3-day leukapheresis procedure. Cytokine-mobilized PBSCs were capable of hematopoietic reconstitution. PBSCs mobilized with pSCF/pIL-3 were infused into an SLA-matched recipient conditioned with cyclophosphamide (50 mg/kg) and total body irradiation 1150 cGy. Neutrophil and platelet engraftment occurred on days 5 and 7, respectively, with minimal evidence of graft-versus-host disease. Complete donor chimerism has been demonstrated 331 days after transplant. CONCLUSIONS: Our preliminary results show that in this well-defined miniature swine model, recombinant swine cytokine combinations (pSCF, pIL-3 with or without hG-CSF) successfully mobilize a high yield of progenitor cells for allogeneic transplantation. Furthermore, these cytokine-mobilized PBSCs demonstrate the potential to reconstitute hematopoiesis and provide long-term engraftment in miniature swine.

Animals↗
PubMed2000

Intentional induction of mixed chimerism and achievement of antitumor responses after nonmyeloablative conditioning therapy and HLA-matched donor bone marrow transplantation for refractory hematologic malignancies.

Mixed lymphohematopoietic chimerism can be induced in mice with bone marrow transplantation (BMT) after a nonmyeloablative preparative regimen that includes cyclophosphamide, anti-T-cell antibody therapy, and thymic irradiation. These mixed chimeras are resistant to the induction of graft-versus-host disease (GVHD) after delayed donor leukocyte infusions (DLIs), despite a potent lymphohematopoietic graft-versus-host reaction that converts the mixed chimeric state to a full donor one. Based on this animal model, we initiated a trial of nonmyeloablative therapy with HLA-matched or -mismatched donor BMT and DLI for refractory hematologic malignancies. Twenty-one of 36 patients enrolled in this trial received a genotypically (n = 20) or phenotypically (n = 1) HLA-matched donor transplant; results reported here are for those patients only. Preparative therapy consisted of cyclophosphamide in doses of 150 to 200 mg/kg; peritransplant antithymocyte globulin; thymic irradiation (in patients who had not received previous mediastinal radiation therapy); and cyclosporine. Eighteen of 20 evaluable patients developed persistent mixed lymphohematopoietic chimerism as defined by >1% donor peripheral white blood cells until at least day 35 posttransplantation. Ten patients received prophylactic DLI beginning 5 to 6 weeks after BMT for conversion of mixed chimerism to full donor hematopoiesis and to optimize a graft-versus-leukemia effect. Fourteen of 20 evaluable patients (70%) achieved an antitumor response; 8 of these responses were complete, and 6 were partial. Of the 8 evaluable patients who received prophylactic DLI, 6 showed conversion to full donor chimerism. Five of the 9 evaluable patients (56%) who received prophylactic DLI achieved a complete response, compared with 3 of 11 patients (27%) who did not receive prophylactic DLI. Currently 11 patients are alive, and 7 of these are free of disease progression at a median follow-up time of 445 days (range, 105-548 days) posttransplantation. Transplantation-related complications included cyclophosphamide-induced cardiac toxicity in 3 of 21 patients (14%) and grade II or greater GVHD in 6 patients (29%). One patient (5%) died from a complication of BMT, and 1 patient (5%) died from GVHD after 2 prophylactic DLIs were given for conversion of chimerism. In summary, mixed lymphohematopoietic chimerism was reproducibly induced after a novel nonmyeloablative preparative regimen incorporating chemotherapy, peritransplant antithymocyte globulin, and thymic irradiation, allowing for early administration of DLI in 10 of 21 patients. After treatment, striking antitumor responses were observed in the majority of patients with chemotherapy-refractory hematologic malignancies.

Adult↗
PubMed2000

Decreased graft-versus-host disease after haplotype mismatched bone marrow allografts in miniature swine following interleukin-2 treatment.

Graft-versus-host disease (GVHD) is an important complication of bone marrow transplantation after transplants between HLA-mismatched donor/recipient pairs. In mice, giving IL-2 post transplant decreases GVHD in this setting. We studied high-dose IL-2 therapy in pigs. Transplants were carried out after conditioning with fractionated total body radiation and cyclophosphamide. Fourteen pigs received a fully mismatched bone marrow transplant (six with IL-2; eight without IL-2), and six received a single haplotype class II mismatched transplant (three with IL-2; three without IL-2). GVHD was evaluated by skin histology. All fully mismatched recipients had severe GVHD (grade 2-3) and died within 13 to 51 days whether or not they received IL-2. Pigs receiving a one haplotype class II mismatched transplant without IL-2 developed severe skin GVHD lasting for 8-45 days; all died within 57 days. Similar pigs receiving IL-2 post transplant had no or only mild skin GVHD for less than 15 days; two are long-term survivors. Bone Marrow Transplantation (2000) 25, 47-52.

Animals↗
PubMed2000

High-dose cyclophosphamide + carboplatin and interleukin-2 (IL-2) activated autologous stem cell transplantation followed by maintenance IL-2 therapy in metastatic breast carcinoma - a phase II study.

While high-dose chemotherapy and stem cell transplantation is associated with higher complete response rates than conventional chemotherapy in patients with metastatic breast cancer (MBC), its role in conferring a survival advantage is unproven. We report the results of a prospective phase II trial of 33 patients accrued between 1996 to 1998 with chemosensitive MBC, who received cyclophosphamide (Cy) 2000 mg/m2/day and carboplatin (Cb) 600 mg/m2/day for 3 consecutive days, followed by infusion of peripheral blood stem cells cultured in IL-2 for 24 h on day 0 as adoptive immunotherapy. Low-dose interleukin-2 (IL-2) was administered from day 0 to +4 and/or +7 to +11, +14 to +18, +21 to +25, then 5 days per month for 11 months to augment a graft-versus-tumor effect. The results of this study were compared to those of a historical control group treated with an identical high-dose Cb + Cy regimen with SCT but without IL-2 treatment. Only gastrointestinal (GI) toxicity was more frequent in the IL-2 cohort (P = 0.0031). At a median follow-up of 18.6 months, the median progression-free survival (PFS) is 9 months (2.4-40) and the median OS has not been reached yet. The Kaplan-Meier estimated 2 year PFS is 35%, compared with 17% in the control arm (P = 0.73), and the estimated 2 year OS is 78%, compared with 61% in the control arm (P = 0.22). Multivariate analysis showed that ER status was an independent predictor for OS and PFS, and less chemotherapy prior to HDCSCT predicted for a better PFS. These results show that augmenting HDC with IL-2 activated SCT is well-tolerated. Whether a therapeutic advantage is achievable in patients with MBC remains to be determined. Bone Marrow Transplantation (2000) 25, 19-24.

Adolescent↗
PubMed2000

Double-blind, randomized, parallel-group study on the efficacy and safety of oral granisetron and oral ondansetron in the prophylaxis of nausea and vomiting in patients receiving hyperfractionated total body irradiation.

The efficacy and safety of granisetron and ondansetron for the prophylaxis of nausea and vomiting resulting from hyperfractionated total body irradiation (TBI) were assessed. Thirty-four patients randomly received double-blind, oral granisetron (2 mg, 1 h before first daily fraction of radiation) or ondansetron (8 mg, 1.5 h prior to each fraction of TBI). Ninety patients who received the same TBI regimen prior to bone marrow transplantation (BMT), but no 5-HT3-receptor antagonist, were identified and comprised the historical control group. By design, this study was only powered to show a difference between each of the active treatment groups and the historical control group. Significantly more patients given granisetron (33.3%) or ondansetron (26.7%) had zero emetic episodes over 4 days, the primary efficacy end point, than those in the historical control group (0%) (P < 0.01; intent-to-treat). Secondary efficacy end points were also evaluated. During the first 24 h, significantly more patients taking granisetron (61.1%) or ondansetron (46.7%) had zero emetic episodes than patients in the historical control group (6.7%) (P < 0.01). Complete emetic control (no emesis or rescue antiemetic) over 4 days was more frequent in patients taking granisetron (27.8%) or ondansetron (26.7%) compared with the historical control group (0%) (P < 0.01). Significantly fewer patients taking granisetron (18/18), but not those taking ondansetron (12/15), experienced more than five emetic episodes during the 4 days of the study compared with the historical control group (40/90; P < 0.01). Oral granisetron and ondansetron are safe and effective for the prevention of nausea and vomiting resulting from TBI.

Adult↗
PubMed2000

Panel reactive antibodies in women with ovarian cancer undergoing high-dose chemotherapy with peripheral stem cell rescue: a case control study.

High-dose chemotherapy with stem cell support is associated with a period of profound thrombocytopenia. During periods of thrombocytopenia, alloreactive antibodies can limit the effectiveness of platelet transfusion. In this institution, women undergoing high-dose chemotherapy with stem cell support for treatment of their ovarian cancer seemed to have a high incidence of panel reactive antibodies (PRA). To evaluate this further, a case-control study was performed comparing pretransplant PRA values in 22 consecutive women undergoing high-dose chemotherapy as intensification therapy for their ovarian cancer and a control group of 51 women receiving similar or identical therapy for their breast cancer. Parity was similar in both groups. Nonparametric t-test comparison of the two groups demonstrated a significantly higher PRA value in women with ovarian cancer compared to those with breast cancer (p = 0.032). Platelet transfusions were more common in women with ovarian cancer as compared to those with breast cancer (5.45/pt and 4.79/pt), although this difference did not reach statistical significance. This finding suggests that alloimmunization may be a more frequent problem in patients with ovarian cancer than in women with breast cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Nonmyeloablative allogeneic stem cell transplant strategies and the role of mixed chimerism.

Experimental and clinical experiences have demonstrated successsful donor engraftment following nonmyeloablative preparative regimens. These less toxic conditioning strategies may be better tolerated with diminished transplant-related morbidity and mortality. Importantly, the intentional induction of mixed chimerism can be established following nonmyeloablative conditioning. This approach has the potential advantages of inhibiting graft-versus-host disease, presumably secondary to the persistence of host immunoregulatory cells, and providing a platform for the delivery of adoptive cellular immunotherapy with donor leukocyte infusions for patients with an underlying malignancy. This review will describe the preclinical evolution of nonmyeloablative transplant strategies, the rationale for considering these approaches, and the preliminary clinical experience with this novel allogeneic stem cell therapy.

Graft vs Host Disease↗
PubMed1999

Combined histocompatibility leukocyte antigen-matched donor bone marrow and renal transplantation for multiple myeloma with end stage renal disease: the induction of allograft tolerance through mixed lymphohematopoietic chimerism.

BACKGROUND: Experimental and clinical evidence has demonstrated that the establishment of allogeneic chimerism after bone marrow transplantation may provide donor-specific tolerance for solid organ allografts. METHODS: Based on the preliminary results of a clinical trial using nonmyeloablative preparative therapy for the induction of mixed lymphohematopoietic chimerism, we treated a 55-year-old woman with end stage renal disease secondary to multiple myeloma with a combined histocompatibility leukocyte antigen-matched bone marrow and renal transplant after conditioning with cyclophosphamide, antithymocyte globulin, and thymic irradiation. RESULTS: The posttransplant course was notable for early normalization of renal function, the absence of acute graft-versus-host disease, and the establishment of mixed lymphohematopoietic chimerism. Cyclosporine, which was the only posttransplant immunosuppressive therapy, was tapered and discontinued on day +73 posttransplant. No rejection episodes occurred, and renal function remains normal on day + 170 posttransplant (14 weeks after discontinuing cyclosporine). Although there is presently no evidence of donor hematopoiesis, there is evidence of an ongoing antitumor response with a recent staging evaluation showing no measurable urine kappa light chains. The patient remains clinically well and is off all immunosuppressive therapy. CONCLUSION: This is the first report of the deliberate induction of mixed lymphohematopoietic chimerism after a nonmyeloablative preparative regimen to treat a hematological malignancy and to provide allotolerance for a solid organ transplant.

Bone Marrow Transplantation↗
PubMed1999

Mixed lymphohaemopoietic chimerism and graft-versus-lymphoma effects after non-myeloablative therapy and HLA-mismatched bone-marrow transplantation.

BACKGROUND: HLA-mismatched donor bone-marrow transplantation after standard myeloablative conditioning therapy for haematological malignant disorders has been limited by severe graft-versus-host disease (GVHD) and graft failure. We tested a new approach to find out whether lymphohaemopoietic graft-versus-host reactions could occur without excessive GVHD in mixed haemopoietic chimeras produced across HLA barriers with non-myeloablative conditioning. METHODS: Five patients with refractory non-Hodgkin lymphoma underwent bone-marrow transplantation from haploidentical related donors sharing at least one HLA A, B, or DR allele on the mismatched haplotype. Conditioning included cyclophosphamide and thymic irradiation before transplantation, and antithymocyte globulin before and after transplantation. The only other GVHD prophylaxis was cyclosporin. FINDINGS: Four of five patients were evaluable and showed engraftment. Mixed haemopoietic chimerism was established, with a predominance of donor lymphoid tissue and varying degrees of myeloid chimerism. Two patients were in GVHD-free states of complete and partial clinical remission at 460 and 103 days after bone-marrow transplantation. INTERPRETATION: Mixed chimerism can be induced in adult recipients of HLA-mismatched bone-marrow transplantation by a non-myeloablative conditioning regimen. The antilymphoma responses seen in two patients suggest that allogeneic bone-marrow transplantation without myeloablative conditioning might have potent immunotherapeutic benefits.

Adult↗
PubMed1999

Transfer of swine major histocompatibility complex class II genes into autologous bone marrow cells of baboons for the induction of tolerance across xenogeneic barriers.

BACKGROUND: The present study examined the potential role of gene therapy in the induction of tolerance to anti-porcine major histocompatibility complex (SLA) class II-mediated responses after porcine renal or skin xenografts. METHODS: Baboons were treated with a non-myeloablative or a myeloablative preparative regimen before bone marrow transplantation with autologous bone marrow cells retrovirally transduced to express both SLA class II DR and neomycin phosphotransferase (NeoR) genes, or the NeoR gene alone. Four months or more after bone marrow transplantation, the immunological response to a porcine kidney or skin xenograft was examined. Both the renal and skin xenografts were SLA DR-matched to the transgene, and recipients were conditioned by combinations of complement inhibitors, adsorption of natural antibodies, immunosuppressive therapy, and splenectomy. RESULTS: Although the long-term presence of the SLA transgene was detected in the peripheral blood and/or bone marrow cells of all baboons, the transcription of the transgene was transient. Autopsy tissues were available from one animal and demonstrated expression of the SLA DR transgene in lymphohematopoietic tissues. After kidney and skin transplantation, xenografts were rejected after 8-22 days. Long-term follow-up of control animals demonstrated that high levels of induced IgG antibodies to new non-alphaGal epitopes developed after organ rejection. In contrast, induced non-alphaGal IgG antibody responses were minimal in the SLA DR-transduced baboons. CONCLUSIONS: Transfer and expression of xenogeneic class II DR transgenes can be achieved in baboons. This therapy may prevent late T cell-dependent responses to porcine xenografts, which include induced non-alphaGal IgG antibody responses.

Animals↗
PubMed1999

Porcine kidney and heart transplantation in baboons undergoing a tolerance induction regimen and antibody adsorption.

BACKGROUND: Xenotransplantation would provide a solution to the current shortage of organs for transplantation. Our group has been successful in inducing tolerance in mice and monkey models of allogeneic transplantation. The present study attempts to extend the same tolerance-inducing regimen to a pig-to-baboon organ transplantation model. METHODS: Nine baboons underwent a conditioning regimen (consisting of nonmyeloablative or myeloablative whole body and thymic irradiation, splenectomy, antithymocyte globulin, pharmacologic immunosuppression and porcine bone marrow transplantation [BMTx]), which has previously been demonstrated to induce donor-specific allograft tolerance in monkeys. In addition, immunoadsorption of anti-alphaGal antibody (Ab) was performed. Four of the nine baboons received pig kidney transplants (KTx), and one also underwent repeat transplantation with an SLA-matched kidney. Two received heterotopic pig heart transplants (HTx). Three baboons underwent conditioning without organ transplantation for long-term studies of natural Ab kinetics. RESULTS: In the three baboons that received the conditioning regimen without an organ transplant, immunoadsorption reduced Ab by approximately 90%, but recovery of Ab to pretreatment level or higher occurred within 7 days. In contrast, the level of Ab remained low after organ transplant. No Ab to pig antigens other than alphaGal was detected in any baboon before or after BMTx, KTx, or HTx. No graft succumbed to hyperacute rejection. KTx function began to deteriorate within 3-6 days, with oliguria and hematuria progressing to anuria, and the kidneys were excised after 3, 6, 9, 11, and 14 days, respectively. One HTx ceased functioning at 8 days; the second baboon died with a contracting HTx at 15 days. Features of coagulopathy and thrombocytopenia developed in all six transplanted baboons (high D-dimer, prolonged prothrombin time and partial thromboplastin time, and falling fibrinogen) resulting in serious bleeding complications in two baboons, one of which died on day 9. Donor organs showed progressive acute humoral rejection with deposits of IgM, IgG, and complement; a focal mononuclear cellular infiltrate was also observed. The ureter was the earliest structure of the KTx affected by rejection, with progression to necrosis. CONCLUSIONS: This conditioning regimen prevented hyperacute rejection but was ineffective in preventing the return of Ab, which was associated with the development of acute humoral rejection with features of coagulopathy. No baboon developed anti-pig Ab other than alphaGal Ab. Further modifications of the protocol directed toward suppression of production of Ab are required to successfully induce tolerance to pig organs in baboons.

Animals↗
PubMed1999

Effect of pig-specific cytokines on mobilization of hematopoietic progenitor cells in pigs and on pig bone marrow engraftment in baboons.

Mixed hematopoietic chimerism has been found to be a requirement for achieving specific immunologic hyporesponsiveness. Some of the requirements for in vitro and in vivo coexistence of discordant hematopoietic systems in the pig-to-baboon (or human) model have been investigated. We have tested the efficacy of pig-specific cytokines (PSC) (IL3, SCF, GM-CSF) in the mobilization of porcine bone marrow (BM) progenitors in vivo (i) in the pig and (ii) in baboons that underwent a conditioning regimen and porcine BM transplantation. In a preliminary in vitro study, porcine BM cells were incubated in various media to assess the effect of human plasma on pig progenitors in a colony-forming unit (CFU) assay. In in vivo studies, four pigs received PSC and one control pig did not. Six baboons underwent natural antibody removal, with subsequent pig BM transplantation. Four of these six underwent nonmyeloablative (n=2) or myeloablative (n=2) conditioning and all received PSC treatment. Two baboons did not receive PSC, one of which underwent a nonmyeloablative regimen. Sequential blood samples and BM biopsies in pigs and baboons were analyzed by CFU assay for the detection of porcine cells. Baboon samples were analyzed by polymerase chain reaction (PCR) to detect porcine DNA. In the case of the in vitro tests, colony forming by porcine progenitors was not inhibited by media containing human plasma and for the in vivo tests, PSC increased the number of progenitors in pig BM; mobilization of progenitors into the peripheral blood was observed. PSC-treated baboons which experienced transient depletion of leukocytes < 1,000/ml (as an effect of the conditioning regimen) had porcine BM cells detectable by PCR for as long as day 316 after BM transplantation. In conclusion we found that: (i) under the conditions of these studies, in vitro porcine progenitor cell growth was not inhibited by human plasma containing natural antibody and complement; (ii) PSC treatment led to an increased number of progenitors in pig BM and peripheral blood; (iii) the combination of an effective conditioning regimen and treatment with PSC was capable of inducing long-term survival of pig progenitors in baboons, although only a low level of engraftment was achieved.

Animals↗