Effect of sarpogrelate hydrochloride,a 5-hydroxytryptamine2 receptor antagonist,on allograft arteriosclerosis after aortic transplantation in rats

BackgroundSarpogrelate hydrochloride, a 5-hydroxytryptamine₂ receptor antagonist, is known to prevent serotonin-induced neointimal hyperplasia. We examined the effect of this agent on allograft arteriosclerosis in a rat model of aortic transplantation.MethodsRats were given an aortic isograft or allograft and oral administration of either saline vehicle alone or 20 mg/kg daily of sarpogrelate for 8 weeks. The grafts were then harvested, and the lumen diameter and the thickness of the intima and media were measured. Comparisons were made between measurement results in isografts and allografts from rats treated and not treated with sarpogrelate. Immunohistochemistry assessments were used to detect expression of serotonin in graft specimens.ResultsFor both allografts and isografts, significantly less intimal thickening was observed in specimens from rats given sarpogrelate compared with rats given saline. Sarpogrelate had no effect on medial thickening in either graft type. Serotonin was detected in allografts from rats given saline alone but not in allografts from rats given sarpogrelate or in isografts.ConclusionsSarpogrelate hydrochloride may mitigate arteriosclerosis in allografts. Platelet aggregation and serotonin may be correlated with intimal thickening associated with chronic rejection.     

Donor IL-4-treatment induces alternatively activated liver macrophages and IDO-expressing NK cells and promotes rat liver allograft acceptance

Most approaches to transplant tolerance involve treatment of the recipient to prevent rejection. This study investigates donor treatment with IL-4 for its effect on subsequent rat liver allograft survival. Rat orthotopic liver transplants were performed in rejecting (PVG donor to Lewis recipient) or spontaneously tolerant (PVG to DA) strain combinations. Donors were untreated or injected intraperitoneally with IL-4 (30,000 U/day) for 5 days. Tissue infiltrates and gene expression were examined by immunohistochemistry and real-time quantitative PCR. IL-4 induced a marked leukocyte infiltrate in donor livers prior to transplant. Macrophages comprised the major population, although B cells, T cells and natural killer (NK) cells also increased. IL-4-induced liver macrophages had an alternatively activated phenotype with increased expression of mannose receptor but not inducible nitric oxide synthase (NOS2). IL-4 also induced IDO and IFN-gamma expression by NK cells. Donor IL-4-treatment converted rejection to acceptance in the majority of Lewis recipients (median survival time > 96 days) and did not prevent acceptance in DA recipients. Acceptance in Lewis recipients was associated with increased donor cell migration to recipient spleens and increased splenic IL-2, IFN-gamma and IDO expression 24 h after transplantation. Donor IL-4-treatment increased leukocytes in the donor liver including potentially immunosuppressive populations of alternatively activated macrophages and IDO-expressing NK cells. Donor treatment led to long-term acceptance of most livers in association with early immune activation in recipient lymphoid tissues.     

Effects of B cell depletion on T cell allogeneic Immune responses: A strategy to reduce allogeneic sensitization

BackgroundB cell depletion has been employed to treat antibody-mediated organ transplantation rejection, although the effects on cellular immune responses have not been extensively investigated.MethodsA model of B cell depletion used SCID/beige mice reconstituted with BALB/c splenocytes either depleted of B cells (BD) or not (BN). BD and B/N mice received C57BL/6 skin grafts and were sacrificed after 6 weeks (BD-S6 and BN-S6).ResultsRecall proliferative responses of BD-S6 splenocytes to C57BL/6 were significantly reduced compared to BN-S6, and central memory T cells' proportions (CD4⁺CD44⁺CD62L⁺ or CD8⁺CD44⁺CD62L⁺) were significantly decreased in BD-S6 spleens. Recall IFN-γ production by BD-S6 splenocytes was significantly reduced compared to BN-S6 splenocytes (p = 0.0028). Survival times of C57BL/6 heart grafts were significantly longer in SCID/beige mice reconstituted with BD-S6 splenocytes (8.5 ± 1.1 days) than for SCID/beige reconstituted with BN-S6 splenocytes (6.0 ± 1.1 days; p = 0.0006). Under cyclosporine therapy, C57BL/6 heart survival was significantly longer for SCID/beige reconstituted with BD-S6 splenocytes (17.5 ± 6.4 days) than those reconstituted with BN-S6 splenocytes (6.2 ± 1.5 days; p < 0.0001).ConclusionB cell depletion during allogeneic sensitization decreased memory T cells and recalls IFN-γ production and reduced second-set allograft rejection.     

Cytokines affecting CD4+ T regulatory cells in transplant tolerance. II. Interferon gamma (IFN-γ) promotes survival of alloantigen-specific CD4+ T regulatory cells

CD4⁺ T cells that transfer alloantigen-specific transplant tolerance are short lived in culture unless stimulated with specific-donor alloantigen and lymphocyte derived cytokines. Here, we examined if IFN-γ maintained survival of tolerance transferring CD4⁺ T cells.Alloantigen-specific transplant tolerance was induced in DA rats with heterotopic adult PVG heart allografts by a short course of immunosuppression and these grafts functioned for > 100 days with no further immunosuppression. In previous studies, we found the CD4⁺ T cells from tolerant rats that transfer tolerance to an irradiated DA host grafted with a PVG heart, lose their tolerance transferring ability after 3 days of culture, either with or without donor alloantigen, and effect rejection of specific-donor grafts. If cultures with specific-donor alloantigen are supplemented by supernatant from ConA activated lymphocytes the tolerance transferring cells survive, suggesting these cells depend on cytokines for their survival. In this study, we found addition of rIFN-γ to MLC with specific-donor alloantigen maintained the capacity of tolerant CD4⁺ T cells to transfer alloantigen-specific tolerance and their ability to suppress PVG allograft rejection mediated by co-administered naïve CD4⁺ T cells. IFN-γ suppressed the in vitro proliferation of tolerant CD4⁺ T cells. Tolerant CD4⁺ CD25⁺ T cells did not proliferate in MLC to PVG stimulator cells with no cytokine added, but did when IFN-γ was present. IFN-γ did not alter proliferation of tolerant CD4⁺ CD25⁺ T cells to third-party Lewis. Tolerant CD4⁺ CD25⁺ T cells' expression of IFN-γ receptor (IFNGR) was maintained in culture when IFN-γ was present. This study suggested that IFN-γ maintained tolerance mediating alloantigen-specific CD4⁺ CD25⁺ T cells.     

Cytokines affecting CD4+ T regulatory cells in transplant tolerance. III. Interleukin-5 (IL-5) promotes survival of alloantigen-specific CD4+ T regulatory cells

CD4⁺ T cells mediate antigen-specific allograft tolerance, but die in culture without activated lymphocyte derived cytokines. Supplementation of the media with cytokine rich supernatant, from ConA activated spleen cells, preserves the capacity of tolerant cells to transfer tolerance and suppress rejection. rIL-2 or rIL-4 alone are insufficient to maintain these cells, however. We observed that activation of naïve CD4⁺ CD25⁺ FOXP3⁺ Treg with alloantigen and the Th2 cytokine rIL-4 induces them to express interleukin-5 specific receptor alpha (IL-5Rα) suggesting that IL-5, a Th2 cytokine that is produced later in the immune response may promote tolerance mediating Treg.This study examined if recombinant IL-5(rIL-5) promoted survival of tolerant CD4⁺, especially CD4⁺ CD25⁺ T cells. CD4⁺ T cells, from DA rats tolerant to fully allogeneic PVG heart allografts surviving over 100 days without on-going immunosuppression, were cultured with PVG alloantigen and rIL-5. The ability of these cells to adoptively transfer tolerance to specific-donor allograft and suppress normal CD4⁺ T cell mediated rejection in adoptive DA hosts was examined. Tolerant CD4⁺ CD25⁺ T cells' response to rIL-5 and expression of IL-5Rα was also assessed.rIL-5 was sufficient to promote transplant tolerance mediating CD4⁺ T cells' survival in culture with specific-donor alloantigen. Tolerant CD4⁺ T cells cultured with rIL-5 retained the capacity to transfer alloantigen-specific tolerance and inhibited naïve CD4⁺ T cells' capacity to effect specific-donor graft rejection. rIL-5 promoted tolerant CD4⁺ CD25⁺ T cells' proliferation in vitro when stimulated with specific-donor but not third-party stimulator cells. Tolerant CD4⁺ CD25⁺ T cells expressed IL-5Rα.This study demonstrated that IL-5 promoted the survival of alloantigen-specific CD4⁺ CD25⁺ T cells that mediate transplant tolerance.     

Chelerythrine ameliorates acute cardiac allograft rejection in mice

The improvement in graft survival over the past decade has been mainly due to calcineurin inhibitors, which interfere with the calcium-mediated pathway. Recently, other pathways such as those mediated by protein kinase C (PKC) are coming into view. The purpose of this study was to assess the immunosuppressive properties of chelerythrine, a specific PKC inhibitor, in preventing acute rejection in murine heterotopic heart transplantation. Mice were randomly divided into control and chelerythrine treated group. The control group received PBS while the chelerythrine treated group was given intraperitoneal injection doses (1, 5, 10 mg/kg) of chelerythrine from day 0 to day 14 after heart transplantation. Six days after transplantation, cardiac allografts were harvested for further tests. The mean survival time (MST) of the cardiac allograft in untreated animals was 8 days while graft MSTs observed in chelerythrine treated group was 13 and 23 days at 5 and 10 mg/kg treatment doses, respectively (P < 0.05). Histologic assessment of the allograft in chelerythrine group showed a significant decline in histologic rejection score, as well as CD4 + and CD8 + T cell infiltration and ICAM-1 + endothelial cell activation. Down-regulation of Th1/Th2 cytokine expression was observed in chelerythrine treatment group. Meanwhile, chelerythrine was also found to inhibit the dephosphorylation of phosphorylated nuclear factor of activated T cells (NFAT) protein 1 and 4.     

Detection of plasma cells,C4d deposits and donor-specific antibodies on sequential graft biopsies of renal transplant recipients with chronic dysfunction

BackgroundIn order to look for a relationship between humoral mechanisms of rejection and chronic allograft dysfunction, plasma cells, C4d deposits and donor-specific antibodies (DSA) were simultaneously sought on serial biopsies of kidney allograft recipients.Patients and methodsTen recipients with chronic dysfunction (G1) and 8 recipients with long-term normal graft function (G2) were included. Biopsies and serums were sampled at early graft dysfunction (T1), between 8 months and 2 years (T2) and after the third year following transplantation (T3).ResultsIn G1, plasma cells represented 12.3% (T1), 8.2% (T2) and 14.1% (T3) of mononuclear cells. The mean percentage of plasma cells was 11.6% in G1 versus 0.4% in G2 (p < 0.05). A progressive rise in C4d deposits was seen in G1, from 25% at T1 to 80% at T3. Donor-specific antibodies were identified in at least one serum sample of 60% of the patients in G1 and 12.5% of the patients in G2 (p = 0.012), whereas donor-specific antibodies were eluted from at least one biopsy of 50% of the patients in G1 and 12.5% of the patients in G2 (p = 0.03). In G1, C4d deposits were significantly associated with plasma cells (p = 0.0012) and anti-HLA Abs in serum samples and/or eluates (p = 0.026).ConclusionThis study shows that plasma cells, DSA and C4d are associated in renal transplants developing chronic rejection.     

Pretransplant serum BAFF levels are associated with pretransplant HLA immunization and renal allograft survival

BackgroundThe essential function of B cell–activating factor (BAFF) is regulating the survival and differentiation of B cells. The link between pretransplant BAFF levels and pretransplant alloimmunization and its value to predict subsequent acute antibody-mediated rejection (AMR) and outcome after renal transplantation is not fully understood.MethodsObjective of our retrospective single-center study was to determine, by ELISA analysis of pretransplant serum BAFF levels in 249 patients undergoing renal transplantation, association between preformed anti-human leukocyte antigen (HLA) antibodies, occurrence of acute antibody mediated rejection (AMR) and renal allograft survival.ResultsPretransplant serum BAFF levels were significantly higher in presensitized recipients with anti-HLA antibodies (3262 ± 2796 pg/ml) than in recipients without occurrence of anti-HLA antibodies (2252 ± 1425 pg/ml; p < 0.0001). In addition, pretransplant BAFF levels correlated with cumulative MFI values of anti-HLA antibodies (r = 0.2966, p = 0.0025). Patients with high pretransplant BAFF levels (≥ 2137 pg/ml) experienced significantly lower allograft survival rates compared to low pretransplant BAFF levels (80% vs. 91%; p = 0.01). Coexistence of high pretransplant BAFF levels and posttransplant AMR was associated with the worst allograft survival rates (56%). Relative risk (RR) for allograft loss was associated with high serum BAFF levels (RR 2.3; p = 0.02), presence of anti-HLA antibodies (RR 2.5; p = 0.007) or anti-HLA -donor-specific antibodies (DSAs) (RR 2.6; p = 0.003) before transplant and AMR post transplant (RR 2.5; p = 0.007). AMR was the strongest independent risk factor for allograft failure (RR 2.6; p = 0.03).ConclusionElevated pretransplant serum BAFF levels negatively affect renal allograft survival and represent a risk factor for allosensitization and subsequent AMR.     

Transplant long-surviving induced by CD40-CD40 ligand costimulation blockade is dependent on IFN-γ through its effect on CD4(+)CD25(+) regulatory T cells

BackgroundIFN-γ was documented to be commonly associated with acute rejection. In the present study, we investigated the role of IFN-γ in the transplant long-surviving induced by blocking CD40–CD40 ligand (CD40–CD40L) costimulation and its mechanisms.MethodsIFN-γ expression in cardiac allografts and spleens from syngeneic and allogeneic recipients with or without anti-CD40L monoclonal antibody (MR-1) treatment was examined by real-time RT-PCR. The grafts survival time in Wild type (IFN-γ^+/+) and IFN-γ deficient (IFN-γ^?/?) recipients was investigated. Mixed lymphocyte reaction (MLR) of CD4⁺ T cells and cytotoxic T lymphocyte (CTL) assay of CD8⁺ T cells were also studied. FoxP3 expression in allografts and spleens from IFN-γ^+/+ or IFN-γ^?/? recipients with MR-1 treatment was examined. Furthermore, FoxP3, IL-10 and CTLA-4 expressions and the suppressive capability of CD4⁺CD25⁺ regulatory T cells were examined.ResultsRejected allografts showed significantly higher IFN-γ expression than long-surviving allografts. Allograft survival was not prolonged in nonimmunosuppressed IFN-γ^?/? mice. Administration of MR-1 induced long-term survival in 90.1% of IFN-γ^+/+ recipients (98 ± 6.6 days) but failed to do so in IFN-γ^?/? group (16.2 ± 4.0 days). IFN-γ^?/? recipients facilitated the proliferation and CTL generation of T cells. The allografts and spleens from IFN-γ^+/+ recipients contained higher FoxP3 expression than IFN-γ^?/? recipients. Moreover, CD4⁺CD25⁺ T cells from IFN-γ^+/+ recipients displayed a higher FoxP3 and IL-10 expression and suppressive capability.ConclusionIFN-γ plays an important role in the long-surviving induced by blocking CD40–CD40L through inhibiting the function of activated T cells and increasing suppressive capability of CD4⁺CD25⁺ regulatory T cells.     

Absence of CD4CD25 regulatory T cell expansion in renal transplanted patients treated in vivo with Belatacept mediated CD28–CD80/86 blockade

AimsBelatacept is a new recombinant molecule (CTLA4-Ig) that interferes with the second activation signal of T lymphocytes. CTLA4-Ig induced T cell allograft tolerance in rodents but not in primates. We examined the changes in peripheral lymphocyte subsets, including regulatory T cells, in renal transplant patients treated with Belatacept.MethodsA cross-sectional immunological study was carried out 6 months after transplantation in 28 patients enrolled in the Belatacept phase II study. Eighteen patients received Belatacept, mycophenolate mofetil and steroids (Belatacept group), while the control group of 10 patients received cyclosporine, mycophenolate mofetil and steroids (CsA group). Lymphocyte subsets were examined by flow cytometry. Foxp3 mRNA expression was measured by quantitative PCR.ResultsThe number of T lymphocytes and the percentage of CD3+ T cells were similar in both groups. However, the percentage of CD3+ CD4+ T cells was lower in the Belatacept group than in the control CsA group (B = 42.5% ± 13.7 vs CsA = 52.9% ± 9, p < 0.005), and the percentage of CD3+ CD8+ cells was higher in the Belatacept group than in the control (B = 32.9% ± 6.7 vs CsA = 19.5% ± 8.2, p < 0.0002). The percentage of CD19+ cells was similar in both groups. Among CD56+cells, only the percentage of CD16+ cells was significantly higher in the Belatacept group than in the control (B = 82% ± 12 vs CsA = 59.7% ± 25, p = 0.01). Among CD4 and CD8 T cells the percentage of activated lymphocytes expressing CTLA4, HLA-DR or CD40L was similar in both groups. The percentage of CD4+CD25+ T cells was higher in the CsA group. The percentage of regulatory CD4+CD25+ cells with bright CD25 staining was similar in both groups (B = 3.6 ± 2.3% vs CsA = 4.7 ± 1.9%, ns) as was the expression of FoxP3.ConclusionOur results indicated that Belatacept did not induce regulatory T cell expansion in vivo. We suggest that Belatacept treatment should be maintained after transplantation to allow graft acceptance.     

Prevention of GVHD and graft rejection by a new S1P receptor agonist, W-061, in rat small bowel transplantation

BackgroundIn small bowel transplantation (SBTx), inhibition of both graft-versus-host disease (GVHD) and allograft rejection is necessary.MethodsWe investigated the potency of a new sphingosine-1-phosphate receptor agonist, W-061, for these two immune responses in SBTx. W-061 has a completely different molecular structure from FTY720. Heterotopic SBTx was performed from Wistar-Furth (WF) into (WF × ACI) F1 rats as a GVHD model or F1 to WF rats as a rejection model. Recipients were orally given 3 mg/kg/day W-061 for 14 days after SBTx. Recipient survival, body weight, histopathology, lymphocyte subpopulations, and the cytokine profile were evaluated.ResultsW-061 treatment significantly prolonged graft survival over 100 days in four out of six recipients in the GVHD group and over 60 days in three out of six recipients in the rejection group. W-061 strongly inhibited GVHD and rejection as seen histopathologically in comparison with untreated control rats. W-061 caused a significant reduction in donor-derived T cells in target organs and infiltrating T cells in allografts by promoting these cells to home into the secondary lymphoid tissues and sequestrating those cells there. W-061 significantly decreased production of interferon-γ in target organs and allografts.ConclusionTherefore, these data suggest that W-061 has considerable potential as a new therapeutic immunosuppressant in patients with SBTx.     

Bipolar fresh total osteochondral allograft in the ankle: Is it a successful long-term solution?

IntroductionSevere post-traumatic ankle arthritis poses a reconstructive challenge in young and active patients. Although technically demanding and despite unsolved immunological issues, bipolar fresh total osteochondral allograft (BFTOA) represent an intriguing option to arthrodesis and prosthetic replacement. The purpose of this paper is to evaluate the outcomes of a series of 48 ankle BFTOA at 10 years follow up and to investigate the rate of survival long term.Methods58 patients underwent BFTOA, of these 48 were available for follow up. The allograft was prepared with the help of specifically designed jigs and the surgery was performed using either a lateral or a direct anterior approach. Patients were evaluated clinically and radiographically preoperatively, and at a mean 121 ± 18 months of follow-up.ResultsThe AOFAS score improved from 31 ± 11 pre operatively, to 65 ± 25 at the last (p < 0.0005). Fourteen failures occurred, with 70.8% allograft rate of survival. All the surviving allografts showed a reduction of the ankle joint movement, still associated with a satisfactory clinical result.ConclusionThe use of BFTOA represents an intriguing option to arthrodesis or arthroplasty. A satisfactory clinical result associated to a good movement of the transplanted joint is to be expected up to short-mid-term, overtime. Long term, the range of motion (ROM) is progressively decreased up to spontaneous arthrodesis in some cases, still the joint results pain free and patient’s perception is of a well functioning ankle. A deeper knowledge of the immunological behavior of transplanted cartilage is needed in order to improve the durability of this fascinating technique.     

Macrophage-derived interleukin-18 in experimental renal allograft rejection.

BACKGROUND: Interleukin 18 (IL-18) is primarily a macrophage-derived, pro-inflammatory cytokine. As macrophages can act as effector cells in acute rejection, we examined the role of IL-18 in a rat model of acute renal allograft rejection. METHODS: Life-sustaining orthotopic DA to Lewis allograft and Lewis-Lewis isograft kidney transplants were performed. In the same model, macrophage-depleted animals, achieved with liposomal-clodronate therapy, were also studied. Macrophage (ED1+) accumulation and IL-18 expression was assessed by immunohistochemistry. CD11b+ cells (macrophages) were isolated from kidney and spleen by micro beads. Real-time PCR was used to assess IL-18 and INF-gamma mRNA expression in tissue and cell isolates. RESULTS: Allografts, but not isografts, developed severe tubulo-interstitial damage and increased serum creatinine by day 5 (P<0.001). Immunohistochemistry revealed a greater ED1+ cell accumulation in day 5 allografts compared with isografts (P<0.001). IL-18 mRNA expression was increased 3-fold in allografts compared to isografts (P<0.001). Accordingly, IL-18 protein was increased in allografts (P<0.001), and was predominantly expressed by ED1+ macrophages. CD11b+ macrophages isolated from allografts had a 6-fold upregulation of IL-18 mRNA expression compared to isograft macrophages (P<0.001). Macrophage depletion resulted in a marked attenuation of allograft rejection, ED1+ and IL-18+ cells were significantly reduced (P<0.05) as was IL-18 mRNA expression (29.28+/-2.85 vs 62.48+/-3.05, P<0.001). INF-gamma mRNA expression (P<0.01) and iNOS (P<0.001) production were also significantly reduced in the macrophage-depleted animals. CONCLUSION: This study demonstrates that IL-18 is significantly increased during acute rejection and is principally produced by intra-graft macrophages. We hypothesize that IL-18 upregulation may be an important macrophage effector mechanism during the acute rejection process.     

Electroporation-mediated transfer of plasmid DNA encoding IL-10 attenuates orthotopic tracheal allograft stenosis in rats

BackgroundElectroporation has been shown to increase the efficacy of intramuscular injection of plasmid DNA, resulting in a higher level of foreign gene expression. Using this technique, we examined the effect of viral IL-10 gene transfer on the prevention of tracheal allograft stenosis in an animal model.MethodsOn the day of tracheal transplantation, recipient Lewis rats were intramuscularly injected with either plasmid pCAGGS-LacZ or plasmid pCAGGS-viral IL-10, followed immediately by electroporation. Tracheas from Brown Norway donors were transplanted into the backs of Lewis recipients, and the histology of the grafts were assessed 2 and 4 weeks after transplantation.ResultsThe serum level of IL-10 peaked at 2000 pg/ml one day after injection; the level then slowly decreased, but was maintained above 1000 pg/ml until 8 days after injection. At Day 28, the airway lumina of the tracheal allografts were almost completely obliterated by fibroproliferative tissue in the control pCAGGS-LacZ-treated rats. In rats injected once with pCAGGS-viral IL-10, luminal obliteration was significantly decreased compared with the control pCAGGS-LacZ-treated rats (mean luminal opening 46.8% vs 0% p < 0.05). The loss of epithelial cells lining the airway was also decreased in the IL-10-treated group (mean epithelial coverage 42% vs 5% p < 0.05). Multiple injections with pCAGGS-viral IL-10 did not further improve the histological changes.ConclusionIL-10 gene transfer by intramuscular injection using electroporation attenuated tracheal allograft stenosis associated with mild epithelial injury.     

Innate immunity alone is not sufficient for chronic rejection but predisposes healed allografts to T cell-mediated pathology

BackgroundAcute allograft rejection is dependent on adaptive immunity, but it is unclear whether the same is true for chronic rejection. Here we asked whether innate immunity alone is sufficient for causing chronic rejection of mouse cardiac allografts.MethodsWe transplanted primarily vascularized cardiac grafts to recombinase activating gene-knockout (RAG^?/?) mice that lack T and B cells but have an intact innate immune system. Recipients were left unmanipulated, received adjuvants that stimulate innate immunity, or were reconstituted with B-1 lymphocytes to generate natural IgM antibodies. In a second model, we transplanted cardiac allografts to mice that lack secondary lymphoid tissues (splenectomized aly/aly recipients) and studied the effect of NK cell inactivation on T cell-mediated chronic rejection.ResultsAcute cardiac allograft rejection was not observed in any of the recipients. Histological analysis of allografts harvested 50 to 90 days after transplantation to RAG^?/? mice failed to identify chronic vascular or parenchymal changes beyond those observed in control syngeneic grafts. Chronic rejection of cardiac allografts parked in splenectomized aly/aly mice was observed only after the transfer of exogenously activated T cells. NK inactivation throughout the experiment, or during the parking period alone, reduced the severity of T cell-dependent chronic rejection.ConclusionsThe innate immune system alone is not sufficient for causing chronic rejection. NK cells predispose healed allografts to T cell-dependent chronic rejection and may contribute to chronic allograft pathology.     

Blockade of CD27/CD70 pathway to reduce the generation of memory T cells and markedly prolong the survival of heart allografts in presensitized mice

BackgroundAlloreactive memory T cells are a major obstacle to transplantation acceptance due to their capacity for accelerated rejection.MethodsC57BL/6 mice that had rejected BALB/c skin grafts 4 weeks earlier were used as recipients. The recipient mice were treated with anti-CD154/LFA-1 with or without anti-CD70 during the primary skin transplantation and anti-CD154/LFA-1 or not during the secondary transplantation of BALB/c heart. We evaluated the impact of combinations of antibody-mediated blockade on the generation of memory T cells and graft survival after fully MHC-mismatched transplantations.ResultsOne month after the primary skin transplantation, the proportions of CD4⁺ memory T cells/CD4⁺ T cells and CD8⁺memory T cells/CD8⁺ T cells in the anti-CD154/LFA-1 combination group were 47.32 ± 4.28% and 23.18 ± 2.77%, respectively. In the group that included anti-CD70 treatment, the proportions were reduced to 34.10 ± 2.71% and 12.19 ± 3.52% (P < 0.05 when comparing the proportion of memory T cells between the two groups). The addition of anti-CD70 to the treatment regimen prolonged the mean survival time following secondary heart transplantation from 10 days to more than 90 days (P < 0.001). Furthermore, allogenic proliferation of recipient splenic T cells and graft-infiltrating lymphocytes were significantly decreased. Meanwhile, the proportion of regulatory T cells was increased to 9.46 ± 1.48% on day 100 post-transplantation (P < 0.05).ConclusionsThe addition of anti-CD70 to the anti-CD154/LFA-1 combination given during the primary transplantation reduced the generation of memory T cells. This therapy regimen provided a potential means to alleviate the accelerated rejection mediated by memory T cells during secondary heart transplantation and markedly prolong the survival of heart allografts.     

Evolution of secondary hyperparathyroidism in patients following return to hemodialysis after kidney transplant failure

IntroductionSevere uncontrolled secondary hyperparathyroidism and kidney transplantation history are both risk factors for fractures in hemodialyzed patients. Moreover, patients who return to dialysis after transplant failure have more severe infections/anemia and higher mortality risk than transplant-naive patients starting dialysis with native kidneys. In this context, our aim was to test the hypothesis that transplant failure patients have more secondary hyperparathyroidism than transplant-naive patients.MethodsWe retrospectively compared 29 transplant failure patients to 58 transplant-naive patients matched for age, sex, chronic kidney disease duration and diabetes condition (1 transplant failure/2 transplant-naive ratio), who started dialysis between 2010 and 2014. Clinical and biological data were collected at baseline, 6 and 12 months.FindingsAt baseline, neither serum parathyroid hormone (transplant-naive: 386 ± 286 pg/mL; transplant failure: 547 ± 652 pg/mL) nor serum 25-hydroxyvitamin D (transplant-naive: 27.8 ± 17.0 μg/L, transplant failure: 31.1 ± 14.9 μg/L) differed between groups. However, serum parathyroid hormone at 12 months and the proportion of patients with uncontrolled secondary hyperparathyroidism (parathyroid hormone > 540 pg/mL, KDIGO criteria) were significantly higher in transplant failure than in transplant-naive (parathyroid hormone: 286 ± 205 vs. 462 ± 449, P < 0.01; uncontrolled secondary hyperparathyroidism: 30% vs. 13%, P < 0.01, respectively). Within the transplant failure group, patients with uncontrolled secondary hyperparathyroidism at 12 months were younger than patients with normal or low parathyroid hormone.DiscussionThis retrospective and monocentric study suggests that transplant failure patients are more likely to develop secondary hyperparathyroidism. Thus, finding high serum parathyroid hormone in young transplant failure patients, who are expected to undergo further transplantations, should incite physicians to treat early and more aggressively this complication.