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Graft Acceptance (graft + acceptance)
Selected AbstractsThe Effect of Lyophilization on Graft Acceptance in Experimental Xenotransplantation Using Porcine CorneaARTIFICIAL ORGANS, Issue 1 2010Jeong-Kyu Lee Abstract The immunogenicity of lyophilized porcine cornea is unknown. The purpose of this study was to examine the possibility of using lyophilized porcine cornea as a substrate for ocular surface reconstruction. A porcine cornea stromal button was freeze-dried and vacuum-packed. Lyophilized and fresh porcine corneas were examined histologically, and then implanted into intrastromal pockets in live rat corneas. Cytokine concentrations in plasma and protein extracts from the corneal buttons of rats were measured using the fluorokine multianalyte profiling assay, and histologic examination was performed. Immunoreactivity to the ,-gal epitope was not found in lyophilized porcine corneas, whereas it was found in several keratocytes in fresh porcine corneas. The median survival time of rat corneas receiving lyophilized porcine transplants was 28.0 days, significantly longer than the 14.0-day survival of rat corneas that received fresh porcine transplants (P < 0.05). CD45RO+ and CD68+ cells were observed in rejected corneas, and interleukin-2 and interferon-, were elevated in rat plasma and corneal tissue. The lyophilized porcine corneal stroma, which is devoid of ,-gal epitope, is less antigenic, and may be a useful biomaterial for ocular surface reconstruction and corneal collagen supplementation. [source] Initial steroid bolus injection promotes vigorous CD8+ alloreactive responses toward early graft acceptance immediately after liver transplantation in humansLIVER TRANSPLANTATION, Issue 9 2007Hiroto Egawa We have found that steroid bolus withdrawal prior to graft reperfusion increased the incidence of acute cellular rejection (ACR). This study aims to clarify how initial steroid bolus (ISB) injection at reperfusion influences the kinetics of CD8+ alloreactive immune responses immediately after living donor liver transplantation (LDLT). A total of 49 hepatitis C virus (HCV)-infected recipients were classified into 3 groups according to hierarchical clustering by preoperative CD8+CD45 isoforms. The naive T cell proportion was considerably higher in Group I than in Groups II and III, whereas Group II recipients had the highest effector memory (EM) T cells and Group III the highest effector T cells. The frequency of ACR was significantly higher in recipients without ISB than in those with ISB. In particular, the ACR rates were the highest in Group II without ISB. Following ISB, the proportion of effector T cells was promptly upregulated within 6 hours after graft reperfusion, simultaneously with the upregulation of CD27,CD28, subsets, interferon-gamma (IFN-,), tumor necrosis factor-alpha and perforin expression, which significantly correlated with increasing interleukin (IL)-12 receptor beta 1 cells. These were then downregulated to below preoperative levels by tacrolimus (Tac) administered at 24 hours. These changes did not occur in the absence of ISB. In Group II without ISB, the downregulation of IL-12R,1+ cells was the greatest, consistent with the highest rates of ACR and mortality (60%). In conclusion, ISB must be done in place, especially in Group II with preexisting high EM T cells, to enable the development of early allograft acceptance. Liver Transpl 13:1262,1271, 2007, © 2007 AASLD. [source] Early immunological monitoring after pediatric liver transplantation: Cytokine immune deviation and graft acceptance in 40 recipientsLIVER TRANSPLANTATION, Issue 3 2007Jérémie Gras Cytokine deviation may be a factor contributing to graft acceptance. We analyze, in the context of liver transplantation, circulating cytokine levels and their mRNA precursors in liver biopsy samples to study a putative correlation with early immunologic outcome. Forty primary pediatric liver recipients were submitted to a prospective immune monitoring protocol, including 8 of 40 patients with an early, biopsy-proven acute rejection episode. The 32 patients with graft acceptance showed markedly increased interleukin (IL)-10 blood levels at 2 hours after reperfusion on days 1 and 4 after transplantation as compared with baseline, whereas patients with graft rejection only exhibited increased IL-10 levels at 2 hours. A good correlation was observed between IL-10 peripheral levels and levels ascertained by IL-10 reverse transcriptase,polymerase chain reaction at 2 hours and on day 7. Patients with graft acceptance also showed a decrease in interferon gamma (IFN-,) at 1 and 2 hours after reperfusion on days 1, 4, 7, 14, and 28 after transplantation. One patient with graft tolerance who had subsequent immunosuppression withdrawal after posttransplantation lymphoproliferative disease showed a similar intraoperative IL-10 pattern, whereas posttransplantation tumor necrosis factor alpha and IFN-, levels greatly decreased. The occurrence of cytokine immune deviation may therefore be related to early graft acceptance in children who receive liver transplants. Liver Transpl 13:426,433, 2007. © 2007 AASLD. [source] Increased expression of cytotoxic effector molecules: Different interpretations for steroid-based and steroid-free immunosuppressionPEDIATRIC TRANSPLANTATION, Issue 1 2003Thomas Satterwhite Abstract: Cytotoxic T lymphocyte (CTL) effector molecules have been studied as markers of acute rejection in renal allograft recipients on steroid-based immunosuppression. We hypothesized that basal CTL gene expression may vary with time post-transplantation as well as with different immunosuppression protocols (steroid-based or steroid-free). Variations in CTL gene expression may thus impact on the ability to predict acute allograft rejection. We used the non-invasive method of quantitative competitive-reverse transcription-polymerase chain reaction (QC-RT-PCR) to quantify the amounts of CTL effector molecules (granulysin, GL; perforin, P; granzyme B, GB) in serial peripheral blood lymphocyte (PBL) samples from steroid-free and steroid-based adult and pediatric renal allograft recipients. Patients on both protocols were clinically monitored by protocol biopsies at 1, 3, 6, and 12 months post-transplantation and for graft function at 1 yr post-transplantation in a separate clinical study. Steroid-free patients with stable graft function showed an increase in GL, P, and GB gene expression over time post-transplantation with the increase being seen largely by the first post-transplant month. A further increase in GL expression was noted at the end of the first post-transplant year in the absence of acute rejection, whereas GB and P levels were unchanged. At comparative time-points post-transplantation, CTL genes were found to be higher in steroid-free patients with stable graft function, compared to steroid-based recipients with either clinically stable graft function or acute rejection. This study suggests that levels of CTL gene expression, although important in a steroid-based regimen to monitor the risk of acute rejection, may not be similarly applied in patients on steroid-free immunosuppression. The early increase in levels seen in steroid-free patients appears to correlate with the total absence of steroids. As steroid-free patients seem to have a lower incidence of acute rejection and better long-term graft function at 1 yr, the early increase in CTL genes in the absence of acute rejection may suggest an early adaptive immune activation response, promoting early graft acceptance in this protocol. [source] Immunimodulation of corneal epithelial cells following electroporation with mRNA encoding IL-10 and FasLACTA OPHTHALMOLOGICA, Issue 2009N ZAKARIA Purpose The aim of this project is to transfect corneal epithelial cells with mRNA encoding IL-10 and FasL in order to evoke down modulation of allogenic T cell responses in an ex vivo model. Methods The corneal epithelial cells (CECs) will be electroporated initially using a reporter gene, EGFP, in order to optimize the transfection efficiency of the cells which will be detected using flow cytometry. Following this, we intend to transfect the cells with mRNA encoding IL-10 and FasL. The cells will then be labeled with antibodies against IL-10 and FasL and checked for expression of these molecules using flow cytometry. Cytokine secretion will also be detected using ELISA. IL-10 and FasL transfected cells will be co cultured with allogenic T cells and compared with control co cultures of allo-T cells with mock-electroporated CECs. After 5 days of culture, T cells will be analyzed for allogenic reactivity by ELISA for IFN-, production in the culture supernatant. Results We intend to show that it is possible to electroporate corneal epithelial cells effectively ex vivo with a reporter gene as well as with IL-10 and FasL. We hypothesize that this may induce tolerance in allogenic T cells and we intend to illustrate this in an ex vivo model using an epithelial-allo T cell co-culture. Conclusion This project aims to illustrate, in an ex vivo model, how gene insertion into corneal epithelial cells could possibly lead to improved cultivated limbal stem cell graft acceptance in patients with vascularized corneas. [source] In vivo IL-10 and TGF-, production by PBMC from long-term kidney transplant recipients with excellent graft function: a possible feedback mechanism participating in immunological stabilityCLINICAL TRANSPLANTATION, Issue 2 2004Josefina Alberú Abstract:, Background:, Interleukin-10 (IL-10) and transforming growth factor-, (TGF-,) are Th2-derived multifunctional cytokines that exhibit potent immunoregulatory and anti-inflammatory properties which might prolong graft survival. The aim of this study was to explore whether spontaneous production of IL-10 and TGF-, by blood mononuclear cells correlates with excellent long-term graft function. Methods:, A cross-sectional study was carried out in 32 kidney transplant recipients, without albuminuria, treated with azathioprine and prednisone. Spontaneous IL-10 and TGF-, were measured by enzyme-linked immunosorbent assay in supernatants from 24 h cultured unstimulated peripheral blood mononuclear cells. Both cytokines were also determined in 10 healthy kidney donors. Results:, There was no correlation between IL-10 or TGF-, with any variable tested, namely age, SCr, histocompatibility, and post-transplant follow-up. In vivo IL-10 production displayed a statistical trend to be higher in transplant recipients than in controls (362.3 ± 465, range 12.5,1929.3 pg/ml, and 189 ± 170, range 4.17,485.7 pg/ml, respectively; p = 0.08), whereas no difference was observed in TGF-, among the same groups (134.7 ± 79.2, range 68,421 pg/ml, and 121.4 ± 25.8, range 75,151 pg/ml, respectively). Interestingly, a statistically significant inverse correlation was observed between IL-10 and TGF-, in kidney transplant recipients (p = 0.03). Conclusions:, The higher IL-10 production observed in long-term kidney transplant recipients supports the notion that this cytokine contributes in decreasing allogenic immune responses and allows prolongation of allograft survival. The balance between TGF-, and IL-10 may be of paramount importance in graft acceptance. [source] | ||||||||||