The effect of tolerance to noninherited maternal HLA antigens on the survival of renal transplants from sibling donors

BACKGROUND: During pregnancy and nursing, a baby's developing immune system is intimately exposed to the mother's antigens. To determine whether this exposure is of clinical benefit to patients who later receive an allograft as an adult, we analyzed the outcome of primary renal transplantations from sibling donors. METHODS: We retrospectively studied graft survival and rejection episodes in 205 patients who had received renal transplants at nine centers between 1966 and 1996 from sibling donors bearing maternal or paternal HLA antigens not inherited by the recipient. The sibling donors were categorized by analysis of family HLA-typing data. RESULTS: In the multicenter analysis, graft survival was higher at 5 years and at 10 years after transplantation in recipients of kidneys from siblings expressing maternal HLA antigens not inherited by the recipient than in recipients of kidneys from siblings expressing paternal HLA antigens not inherited by the recipient (86 percent vs. 67 percent at 5 years and 77 percent vs. 49 percent at 10 years, P=0.006 for both). Paradoxically, there was a higher incidence of early rejection in the former group, suggesting that fetal and neonatal exposure to maternal antigens results in immunologic priming. Pretransplantation transfusions of donor blood reduced the incidence of acute rejection while preserving the beneficial effect of tolerance to noninherited maternal antigens on graft survival. Since 1986, new immunosuppressive drugs have lessened the short-term, but not the long-term, survival advantage of grafts expressing maternal HLA antigens not inherited by the recipient. CONCLUSIONS: In the transplantation of a kidney from a sibling donor who is mismatched with the recipient for one HLA haplotype, graft survival is higher when the donor has maternal HLA antigens not inherited by the recipient than when the donor has paternal HLA antigens not inherited by the recipient.     

Steroid withdrawal from long-term immunosuppression in liver allograft recipients

Corticosteroids were withdrawn from the immunosuppressive regimen of 168/197 (85%) of liver transplant patients who survived for more than three months. In 14, steroids were restarted for reasons other than rejection. The remaining 154 patients were evaluated for the occurrence of rejection and graft loss. Risk factors for the development of rejection after steroid withdrawal were assessed. There were 13 episodes of rejection in 12 (7.8%) grafts; 7 (4.5%) experienced acute cellular rejection, and 6 (3.9%) developed chronic ductopenic rejection. All cases of acute rejection resolved with high-dose steroids. Graft and patient loss due to chronic rejection was 3 (1.9%) and 2 (1.3%), respectively. Chronic rejection resolved in 1 patient, 1 was successfully retransplanted, and in the other 2 the principal cause of death was recurrent tumor. None of the risk factors examined (primary indication for transplant, severity of previous acute rejection, use of OKT3, retransplantation, ABO blood group donor/recipient match, CMV infection, and CsA mono versus CsA and AZA double therapy) were associated with the development of chronic rejection poststeroid withdrawal. The prevalence of side effects, after steroid withdrawal, was low; 66% of patients never required antihypertensive medication; 14% experienced a significant septic episode, and only 4 died with sepsis as the major factor. There were no fungal sepsis and no new cases of diabetes. Withdrawal of corticosteroids after 3 months can be successfully achieved in the majority of liver allograft recipients and is associated with a low rate of rejection, graft loss, and complications attributable to immunosuppressive medication.     

Determinants of graft survival after renal transplantation

We studied multiple determinants of graft survival at a single center and the effects of nonimmunologic graft loss on transplant survival. This retrospective study examined the results of 589 cadaver donor transplants performed between 1986 and 1992. Graft survival rates were calculated using Kaplan-Meier estimates for both overall graft survival (all causes of graft loss) and immunologic graft survival (function lost due to acute or chronic rejection and noncompliance). Cadaver graft survival was significantly poorer with an increasing degree of DR mismatch (P=0.02). An analysis of pretransplant variables showed graft loss risk was highest with greater DR mismatches, two B-antigen mismatch, higher donor serum creatinine, and younger recipient age. After transplantation, acute rejection was the most significant factor associated with long-term graft survival. Our data demonstrate a significant advantage for zero DR and one DR mismatch cadaver donor transplants, with excellent immunologic graft survival. This study suggests that a combination of immediate graft function, prevention of acute rejection by appropriate early immunosuppressive therapy, and acceptable DR match enhances cadaveric graft survival.     

Acute intracranial complications of temporal bone trauma

BACKGROUND: A total of 110 patients, in whom kidneys from 95 living related and 15 cadaver donor, had experienced renal transplantation between February 1985 and October 1996 in our clinic. This study was conducted to evaluate the influence of the various pre-operative factors to the graft survivals and clinical course of patients in living related renal transplantation. METHODS: In 95 recipients, 17 adult patients had long term graft survivals over 5 years including 6 recurrent or denovo nephritis without chronic allografts nephropathy. Eight failed to graft loss attributed to chronic allografts nephropathy diagnosed within 5 years. Retrospective analysis were performed to elucidate the differences of these recipients. RESULTS: Donors of long graft survival recipients were younger (49.1 +/- 12.1 v.s. 58.9 +/- 10. 2) and had a better renal function evaluated by preoperative creatinine clearance in living related donors (115.5 +/- 37.0 v.s. 79.7 +/- 22.0 1/day). Graft long survival recipients had experienced less frequencies of acute rejection within 6 months (0.53 +/- 0.62: 8 patients, 9 times) compared with chronic allografts nephropathy recipients (1.00 +/- 0.53: 7 patients, 8 times). Long graft survival recipients had better responses to the antirejection therapy. Additionally acute rejection over 6 months were experienced only in chronic allografts nephropathy recipients. Higher serum creatinine level was revealed in recipients with chronic allografts nephropathy at 1 year after transplantation (1.27 +/- 0.27 v.s. 1.88 +/- 0.42 mg/dl). CONCLUSIONS: We concluded that donor age and renal function are related to the graft long survival as background factors. Long graft survival recipients had less frequency of acute rejection and good response to the antirejection therapy. In recipients with of acute rejection and good response to the antirejection therapy. In recipients with chronic allografts nephropathy, serum cretine level had already increased gradually within 1 year.     

Apoptosis within spontaneously accepted mouse liver allografts: evidence for deletion of cytotoxic T cells and implications for tolerance induction

MHC-mismatched liver grafts are accepted spontaneously between many mouse strains. The underlying mechanism(s) is unclear. In the B10 (H2(b)) to C3H (H2(k)) strain combination used in this study, donor T cells within the liver were rapidly replaced within 2 to 4 days of transplantation with those of the recipient. Freshly isolated liver graft-infiltrating cells harvested on days 4 and 7 exhibited strong CTL responses against donor alloantigens. CTL activity was reduced substantially, however, by day 14, although levels of CTL precursors in the spleen and liver remained high. Examination of the liver allografts by in situ terminal deoxynucleotidyltransferase-catalyzed dUTP-digoxigenin nick end labeling on days 4, 7, and 14 after transplantation revealed prominent apoptotic cells dispersed throughout the nonparenchymal cell population. When acute liver allograft rejection was induced by administration of IL-2 from days 0 to 4 post-transplant (median survival time, 5 days), apoptotic activity (day 4) was reduced substantially, whereas CTL activity was enhanced. Nonparenchymal cells isolated from allografts of unmodified recipients 4, 7, and 14 days after transplantation exhibited significantly higher DNA fragmentation after 18-h culture than cells from liver isografts. Moreover, the level was 4 to 5 times higher than that of cells from IL-2-treated mice (on day 4). These observations suggest that T cell deletion, not regulation, may be responsible for spontaneous liver allograft acceptance. The molecular recognition events that cause apoptosis of infiltrating T cells and why this occurs within liver grafts, but not heart or skin grafts, remain to be elucidated.     

Low level of interleukin 10 synthesis during liver allograft rejection

Interleukin 10 (IL-10) is a macrophage and T-cell-derived cytokine with potent immunosuppressive properties. To assess its role in liver allograft rejection, we evaluated the plasma level and in situ production of IL-10 after liver transplantation and designed in vitro studies to asses the effects of IL-10 on the allogeneic response. Normal controls and liver transplant recipients with acute rejection, chronic rejection, other complications (recurrent hepatitis C, biliary complications), or no complications were evaluated. The plasma IL-10 level was measured by an immunoenzymatic technique. IL-10 expression in the liver was detected on frozen liver biopsies by in situ hybridization and immunohistochemistry. Plasma IL-10 levels were not elevated during acute or chronic rejection, when compared with liver recipients with uncomplicated transplants. IL-10 mRNA and protein expressions in the liver graft were restricted to rare scattered sinusoidal cells of transplant recipients with acute or chronic rejection, as well as in those with no complications. In mixed lymphocyte cultures performed with peripheral blood mononuclear cells (PBMC) from normal subjects, IL-10 decreased the cell proliferation in a dose-dependent manner, and this immunosuppression was synergistic with that of cyclosporine or FK506. These findings indicate that IL-10 production is low during allograft rejection. Thus, IL-10 therapy in association with cyclosporine or FK506 might be proposed after liver transplantation.     

Transplantation of pediatric en bloc cadaver kidneys into adult recipients

BACKGROUND: To maximize the renal donor pool, cadaveric pediatric en bloc kidneys have been transplanted as a dual unit by some transplant centers. We compared the short- and long-term outcomes of adult recipients of cadaveric pediatric en bloc renal transplants versus those of matched recipients of cadaveric adult kidneys. METHODS: Thirty-three adults who received pediatric en bloc kidney transplants between April 1990 and September 1997 were retrospectively identified and were compared with 33 matched adults who received adult cadaveric kidney transplants. The groups were identical for transplantation era, immunosuppression, recipient sex, race, cause of renal failure, mean weight, and follow-up duration (37.8 vs. 37.5 months). The mean recipient age study versus control was lower (36.3 vs. 48.9 years, P=0.0003). Results. There was no difference between the en bloc and adult donor groups in the 3-year patient survival rates (95% vs. 87%, P=0.16) or the 3-year graft survival rates (87.3% vs. 84.2%, P=0.35). Further, there was no difference in en bloc patient or en bloc graft survival time stratified by recipient age (14-44 vs. >45 years, P=0.11), en bloc donor age (<24 vs. >24 months, P=0.39), or recipient weight (<60, 61-75, >75 kg; P=0.60). Differences in serum creatinine (mg/dl) for the en bloc versus the control group at the time of discharge (3.0 vs. 7.8 mg/dl, P=0.06), at 1 year (1.4 vs. 2.0 mg/dl, P=0.06), and at 2 years (1.1 vs. 1.6 mg/dl, P=0.14) had dissipated by the time of the 5-year follow-up examination (1.1 vs. 1.6 mg/dl, P=0.14). Vascular complications were more prevalent in the en bloc group: renal vein thrombosis (one case), thrombosis of donor aorta (two cases), arterial thrombosis of one renal moiety (two cases), and renal artery stenosis (two cases). There were no differences between groups in delayed graft function, acute or chronic rejection, posttransplant hypertension, posttransplant protein-uria, or long-term graft function. CONCLUSIONS: Collectively, these data indicate that transplanting pediatric en bloc kidneys into adult recipients results in equivalent patient and graft survival compared with adult cadaveric kidneys. Further, the data also suggest that pediatric en bloc kidneys need not be strictly allocated based on recipient weight or age criteria.     

Histological and clinical outcome after liver transplantation for hepatitis C

Hepatitis frequently recurs after liver transplantation for hepatitis C. However, the histological progression of disease, predictors of recurrence and disease severity, and patient survival remain uncertain. Fifty-five patients with cirrhosis caused by chronic hepatitis C underwent liver transplantation between January 1990 and December 1993. Hepatitis C genotype was determined, and liver biopsies were performed at frequent intervals posttransplantation. The median follow-up time was 40.4 months. The cumulative rate of survival was no different in liver transplant recipients for hepatitis C than in liver transplant recipients for other chronic liver diseases (P = .62). Histological recurrent hepatitis C developed in 33 of 50 patients assessable for disease recurrence; the median recurrence-free survival time was 13.4 months. Histological activity and stage were mild in most cases. Only 2 patients developed cirrhosis, and no patient required a second transplantation for recurrent disease. Patients with acute cellular rejection had a shorter recurrence-free survival (P = .0141). In patients with recurrent hepatitis, rejection also was correlated with increased histological grade 2 years after transplantation (P = .0061). Recurrence-free survival was decreased in patients infected with genotype 1 (1a and 1b combined) compared with genotypes 2 and 3 combined (P = .02), whereas there was no difference between genotypes 1a and 1b (P > .80). Only patients infected with genotype 1a or 1b developed bridging fibrosis or cirrhosis. In addition, patients who had an early recurrence had a greater risk of progressing to bridging fibrosis or cirrhosis (hazard ratio, 5.1; P = .0473). In our experience, recurrent hepatitiS C after liver transplantation in most cases is mild and survival is unaffected. Both acute cellular rejection and infection with genotype 1 are independent risk factors for reduced recurrence-free survival, and early recurrence is associated with a higher risk of disease progression.     

Antibody- and cell-mediated immune responses of Actinobacillus pleuropneumoniae-infected and bacterin-vaccinated pigs

The number involved in and the rate of migration of donor leucocytes into the following recipient organs (spleen, thymus, bone marrow, lung and mesenteric lymph nodes) were measured in two rat models of orthotopic liver transplantation (OLT) using donor-specific MHC class I antibodies. The first OLT model is one that does not require immunosuppression in order to achieve tolerance and involved the transplantation of DA (MHC haplotype, RT1a) livers into PVG (RT1c) recipients. The second model was one that required a 7-day (10 mg/kg) treatment with cyclosporin A (CsA) to achieve tolerance and used DA donors into Lewis (RT1(1)) recipients. Recipient organs were biopsied on days 3, 20 and 87 following OLT and donor leucocyte migration was quantified by immunohistochemistry and computer densitometry of immunoblots of detergent-solublized tissues in order to resolve both membrane-bound and soluble donor MHC class I antigen. In a separate experiment, spleen biopsies were taken following OLT on days 3 and 15 from the naturally tolerizing OLT model (DA into PVG), treated with and without CsA for 7 days and compared with the (DA into Lewis) model. The initial rate of leucocyte migration between days 3 and 21 following OLT was found to be the most rapid into the spleen, followed by the bone marrow and mesenteric lymph nodes in the naturally tolerant (DA into PVG) model when compared with the (DA into Lewis) model. The number of donor leucocytes in the spleen and mesenteric lymph nodes in both models was, however, approximately the same by 87 days. No real difference in the rate of leucocyte migration was seen in the thymus or the lung for both transplant models over the time course assayed. CsA was found to lower the rate of donor leucocyte migration only over the period it was administered. The rate of donor leucocyte migration into the spleen was still much lower 15 days after OLT in the (DA into Lewis) model compared with the (DA into PVG) model treated with and without CsA. Thus the differences in the rate of donor leucocyte migration into the spleen, bone marrow and mesenteric lymph nodes immediately following OLT may offer an explanation as to why the (DA into PVG) combination is able to accept a transplanted liver without immunosuppressive therapy.     

Renal function improves in liver transplant recipients when switched from a calcineurin inhibitor to sirolimus

Sirolimus (Rapamune; Wyeth-Ayerst, Philadelphia, PA) is a newer immunosuppressive drug with no known acute or chronic nephrotoxic effects; however, limited data are available in liver transplant recipients. We prospectively evaluated changes in renal function in liver transplant recipients after conversion from a calcineurin inhibitor to sirolimus monotherapy. We measured serial serum creatinine levels in liver transplant recipients with chronic nephrotoxicity caused by calcineurin inhibitors before and after conversion to sirolimus therapy. Estimated glomerular filtration rate (eGFR) was calculated from the Modification of Diet in Renal Disease formula. Change in eGFR over time, incidence of acute hepatocellular rejection, and adverse events while being administered sirolimus monotherapy were recorded. Mean interval between liver transplantation and initiation of sirolimus therapy was 310 weeks (range, 9 to 780 weeks). Of 21 patients included in our study, 18 patients were converted to sirolimus monotherapy and 3 patients were switched to sirolimus and low-dose steroid therapy. Patients were followed up for a mean of 66.8 +/- 38.9 (SD) weeks after conversion. Renal function improved in 71% of patients (15 of 21 patients). Median eGFR improved significantly from 34 mL/min/1.73 m2 at the time of conversion to 43 mL/min/1.73 m2 at the last follow-up (27% increase in eGFR; P = 001). Median monthly change in eGFR was from -0.25 mL/min/1.73 m2 pre-sirolimus therapy to +1.28 mL/min/1.73 m2 post-sirolimus therapy (P =.09). Adverse events were mostly mild and self-limited. Only 1 patient developed biopsy-proven acute cellular rejection, which was treated with sirolimus and mycophenolate mofetil. Two patients discontinued sirolimus therapy because of toxicity (oral ulceration, 1 patient; interstitial pneumonitis, 1 patient). Renal function improved significantly in the majority of liver transplant recipients with renal insufficiency caused by calcineurin inhibitors when converted to sirolimus therapy. Sirolimus monotherapy provided adequate immunosuppression with a low incidence of acute cellular rejection and minimal adverse events.     

Influence of advanced recipient and donor age on the outcome of corneal transplantation. Australian Corneal Graft Registry

AIMS: The aims of this study were to examine the influence of advanced recipient and donor age on the long term outcome of corneal transplantation. METHODS: Records of 1036 penetrating corneal grafts in recipients aged > or = 80 years at surgery (defined as the elderly subset) and 8092 donor corneas used for transplantation were obtained from the Australian Corneal Graft Register database, Kaplan-Meier graft survival plots were compared using log rank statistics. RESULTS: Elderly recipients constituted 15% of the recipient pool. The major indication for corneal transplantation in the elderly was bullous keratopathy. Graft survival fell with increasing recipient age (p < 0.00001); the major cause of graft failure was rejection (33%). The desired outcome in 51% of cases was to improve vision and in 42% of cases to relieve pain; 23% of elderly recipients achieved a Snellen acuity of 6/18 or better in the grafted eye and 66% recorded improved acuity after transplantation. Elderly recipients suffered more complications and comorbidities in the grafted eye than did younger recipients. Donor age (stratified in 10 year intervals) did not influence corneal graft survival significantly (p = 0.10). CONCLUSIONS: Elderly graft recipients fared less well after corneal transplantation than did younger recipients, but outcomes in terms of long term graft survival and visual rehabilitation were still good. Donor age did not affect graft survival.     

Prevention of marrow graft rejection without induction of graft-versus-host disease by a cytotoxic T-cell clone that recognizes recipient alloantigens

In allogeneic marrow transplantation, donor T cells that recognize recipient alloantigens prevent rejection but also cause graft-versus-host disease (GVHD). To evaluate whether the ability to prevent marrow graft rejection could be dissociated from the ability to cause GVHD, we generated a panel of four different CD8 cytotoxic T-lymphocyte clones specific for H2(d) alloantigens. Three of the clones caused no overt toxicity when as many as 20 x 10(6) cells were infused intravenously into irradiated H2(d)-positive recipients, and one clone caused acute lethal toxicity within 1 to 3 days after transferring 10 x 10(6) cells into H2(d)-positive recipients. One clone that did not cause toxicity was able to prevent rejection of (C57BL/6J x C3H/HeJ)F1 marrow in 800 cGy-irradiated (BALB/cJ x C57BL/6J)F1 recipients without causing GVHD. Large numbers of cells and exogenously administered interleukin-2 were required to prevent rejection. These results with different CD8 clones suggest that GVHD and prevention of rejection could be separable effects mediated by distinct populations of donor T cells that recognize recipient alloantigens.     

Immunization of pigs against Streptococcus suis serotype 2 infection using a live avirulent strain

BACKGROUND: To reduce the mortality rate associated with liver transplantation, it is important to identify the risk factors for increased mortality among liver transplant recipients. It has been suggested that cytomegalovirus (CMV) infection is one such risk factor, but no studies have examined mortality rates associated with the CMV serologic status of the donor and recipient by using multivariate techniques. OBJECTIVE: To study the effect of CMV on 1-year mortality rates in orthotopic liver transplant recipients. DESIGN: Intention-to-treat analysis of a cohort. PATIENTS: 146 liver transplant recipients who were enrolled in a multicenter, randomized, placebo-controlled intervention trial. SETTING: Four university-affiliated transplantation centers. RESULTS: 1-year mortality rates for the four strata of donor and recipient CMV serologic status before transplantation were as follows: seronegative donor and recipient, 11%; seronegative donor and seropositive recipient, 22%; seropositive donor and recipient, 30%; and seropositive donor and seronegative recipient, 44% (P = 0.0091). Multivariate analysis using a time-dependent Cox proportional hazards model showed that retransplantation (relative risk, 4.6 [95% CI, 1.9 to 10.7]; P < 0.001); total number of units of blood products administered during transplantation (relative risk, 1.006 per unit [CI, 1.003 to 1.010]; P < 0.001); and presence of CMV disease (relative risk, 3.9 [CI, 1.8 to 8.5]; P < 0.001), invasive fungal disease (relative risk, 3.3 [CI, 1.5 to 7.1]; P = 0.0020), and bacteremia (relative risk, 2.5 [CI, 1.2 to 5.2]; P = 0.0136) were independently associated with higher mortality rates. If post-transplantation variables that were highly correlated with donor and recipient CMV serologic status were restricted from the model, donor and recipient CMV serologic status was the only pretransplantation variable independently associated with higher mortality rates (P = 0.002). CONCLUSION: Donor and recipient CMV serologic status is a significant pretransplantation determinant for death in liver transplant recipients.     

Can the liver with Gilbert's syndrome be used as graft of living-related liver transplantation?

Gilbert's syndrome is the common cause of non hemolytic unconjugated hyperbilirubinemia with a prevalance of 3-7%. Gilbert's syndrome may introduce a selection of potential liver donors from brain death patients. We present a case of living-related liver transplantation (LRLT) from a donor with Gilbert's syndrome. A 22-year-old woman had been diagnosed as having liver cirrhosis at the age of 5. She underwent liver transplantation with the donor's left lobe as the graft. The donor, who was the father of the patient, had been diagnosed with Gilbert's syndrome. Although the recipient was well until 11 months after surgery, she died of subacute fulminant hepatitis 16 months after surgery. However, it was clear that the liver with Gilbert's syndrome could be used as a graft of living-related liver transplantation for adult recipients.     

Increase in Ca(2+)-permeability of the plasma membrane during radiation-induced apoptosis of thymocytes]

BACKGROUND: We previously reported excellent outcome at 6 months after transplantation in recipients of expanded criteria donor kidneys that other local centers had declined, kidneys that nobody wanted (KNW), versus controls. We now report follow-up after 23 months. METHODS: We retrospectively reviewed 27 donor and 24 recipient characteristics in 126 adult recipients of transplants from January 1, 1995, to November 25, 1996. RESULTS: Donors of control kidneys versus KNW were younger and had significantly higher minimum 4-hr urine output. Recipients of control kidneys versus KNW had significantly more HLA matches and lower 3-month posttransplant serum creatinine levels. Patient and graft survival rates were similar between the control kidneys versus the KNW. We also compared the control kidneys and KNW with regard to prompt function or delayed graft function and satisfactory versus unsatisfactory function (unsatisfactory: serum creatinine > or =2.5 ml/dl or graft loss at 6 months) to identify donor and recipient characteristics associated with delayed graft function and unsatisfactory outcome. The incidence of rejection was significantly lower in control kidneys and KNW with satisfactory function versus control kidneys and KNW with unsatisfactory function. CONCLUSIONS: These data demonstrate: (1) similar graft survival at 12 months, (2) lower donor age, (3) higher minimum 4-hr urine output, and (4) more HLA matches in recipients of control kidneys versus KNW. Optimal outcome was achieved in recipients of control kidneys and KNW with prompt function and satisfactory function based upon serum creatinine in the first 6 months and in recipients with lower rates of rejection. Although outcome is dependent upon many donor and recipient variables, we believe that with careful donor and recipient selection, excellent outcome can be achieved using expanded criteria donor kidneys.     

Comparison of the growth and fate of fetal spinal iso- and allografts in the adult rat injured spinal cord

Most studies investigating early fetal CNS graft-host interactions and host immune responses have been performed using intracerebral transplantation paradigms. The purpose of this study was to establish the early developmental dynamics of fetal graft integration with the injured host spinal cord and to determine whether fetal allografts in this environment are subject to rejection. ACI rat fetal spinal cord (FSC) tissue was grafted into acute lesion cavities of adult WF rat spinal cords. Graft development and/or rejection was followed from 1 to 45 days posttransplantation with morphometric, histological, and immunocytochemical methods. We determined that all FSC grafts in acute resection lesions of the adult rat spinal cord undergo an early substantial cellular attrition, but following favorable attachment to healthy host tissue margins, they rebound and grow to fill the lesion cavity by approximately 45 days. We also determined that FSC allografts into nonimmunosuppressed adult recipients are consistently rejected, but only after an early period of growth and maturation. The onset of rejection is characterized by extensive cellular infiltration coincidental with graft and host MHC antigen expression. The implications of delayed graft development and graft-host integration are discussed relative to interconnectivity and long-term potential for graft-derived benefits. The observed rejection response was characteristic of first-order allograft rejection and underscores a lack of immunological privilege in the microenvironment of the injured spinal cord.     

Donor cardiac troponin T: a marker to predict heart transplant rejection

BACKGROUND: Noninvasive methodologies have shown poor sensitivity in predicting rejection when compared to serial endomyocardial biopsies. We studied the potential role of donor blood troponin T (Tn-T) as a marker for predicting heart transplant rejection. METHODS: Blood cardiac Tn-T was measured from 16 heart donors. Transplant rejection and cardiac function in the recipients were monitored for 1 year. RESULTS: When data were analyzed based on donor blood Tn-T levels, 6 patients who received hearts from donors with low Tn-T (<0.45+/-0.1 ng/mL) showed no rejection, and patients whose hearts came from donors with higher Tn-T (6.01+/-0.81 ng/mL) developed episodes of high-grade rejection (3A) within 38.5+/-2.1 days after transplantation. Eight patients who received hearts from donors with intermediate levels of Tn-T (3.57+/-0.55 ng/mL) showed mild rejection (grade 1). All recipients had qualitatively normal left ventricular systolic function by serial echocardiography. The mean donor ischemic time was 169+/-47 minutes. CONCLUSIONS: The quality of the donor heart is an important prognostic factor in heart transplantation. It may be possible to identify severely damaged donor organs before transplantation and avoid their use or to develop more aggressive strategies for reducing recurrent acute rejection episodes in high-risk patients.     

Delayed function reduces renal allograft survival independent of acute rejection

BACKGROUND: Mechanisms by which delayed allograft function reduces renal allograft survival are poorly understood. This study evaluated the relationship of delayed allograft function to acute rejection and long-term survival of cadaveric allografts. METHODS: 338 recipients of cadaveric allografts were followed until death, resumption of dialysis, retransplantation, loss to follow-up, or the study's end, which ever came first. Delayed allograft function was defined by dialysis during the first week following transplantation. Multivariate Cox proportional hazards survival analysis was used to assess the relationship of delayed allograft function to rejection and allograft survival. RESULTS: Delayed allograft function, recipient age, preformed reactive antibody levels, prior kidney transplantation, recipient race, rejection during the first 30 days and rejection subsequent to 30 days following transplantation were predictive of allograft survival in multivariate survival models. Delayed allograft function was associated with shorter allograft survival after adjustment for acute rejection and other covariates (relative rate of failure [RR]+1.72 [95% CI, 1.07, 2.76]). The adjusted RR of allograft failure associated with any rejection during the first 30 days was 1.99 (1.23, 3.21), and for rejection subsequent to the first 30 days was 3.53 (2.9 08, 6.00). The impact of delayed allograft function did not change substantially (RR=1.84 [1.15, 2.95]) in models not controlling for acute rejection. These results were stable among several subgroups of patients and using alternative definitions of allograft survival and delayed allograft function. CONCLUSIONS: This study demonstrates that delayed allograft function and acute allograft rejection have important independent and deleterious effects on cadaveric allograft survival. These results suggest that the effect of delayed allograft function is mediated, in part, through mechanisms not involving acute clinical rejection.     

Induction of allograft nonresponsiveness after intrathymic inoculation with donor class I allopeptides. I. Correlation of graft survival with antidonor IgG antibody subclasses

We have recently demonstrated that cardiac allograft rejection in the PVG.R8-to-PVG.1U rat strain combination involves the recognition of a isolated class I (RT1.Aa) molecules as peptides in the context of the recipient MHC molecules. Three synthetic peptides (P1, P2, and P3) corresponding to the alpha-helices of the RT1.Aa molecule served as T-cell epitopes for graft rejection. In this study, we demonstrate that two of these peptides (P2 and P3) are sufficient to induce immune nonresponsiveness (median survival time >237 days) to cardiac allografts when presented to the recipient immune system in the thymus 7 days before transplantation. This effect was time dependent, as intrathymic inoculation 60 days before transplantation did not prolong graft survival (median survival time=12 days). Previous studies have demonstrated a critical role for alloantibody responses in mediating graft rejection in this rat strain combination. We, therefore, studied the role alloantibody responses may play in the observed immune nonresponsiveness. The titers of alloantibody in serum samples harvested from graft recipients at different times after transplantation were measured. We used recipient primary aortic endothelial cells genetically manipulated to express the donor RT1.Aa molecule as targets in an enzyme-linked immunosorbent assay. High titers of anti-RT1.Aa IgM antibody were detected in unmanipulated controls at the time of graft rejection. The IgM antibody switched to high IgG titers in intrathymically inoculated rats with accelerated or delayed rejection. Graft rejection in intrathymically manipulated recipients that had achieved a transient state of immunological nonresponsiveness correlated with higher titers of the IgG2b alloantibody. In marked contrast, the long-term graft survivors expressed undetectable or low levels of the IgG2b antibody and moderate to high levels of the IgG1 and IgG2a subclasses. These data suggest that the IgG2b alloantibody may contribute to the rejection reaction, whereas IgG1 and IgG2a may be involved in active enhancement of graft survival.     

Structure of CheA, a signal-transducing histidine kinase

BACKGROUND/AIMS: After liver transplantation for autoimmune hepatitis, the long-term results and the incidence of recurrence of primary disease are unknown. METHODS: In this retrospective study we reviewed the clinical course of 25 patients transplanted for autoimmune hepatitis and followed for a mean of 5.3 years (2-8.5 years). RESULTS: The actuarial 5-year patient and graft survival rates were 91% (+/-6%) and 83% (+/-8%). The actuarial 1-year rate of acute rejection was 50% (+/-10.2%), which was comparable to that of patients transplanted for primary biliary cirrhosis and primary sclerosing cholangitis. Autoantibodies persisted in 77% of patients, at a lower titer than before liver transplantation. Ten patients were excluded from the study of autoimmune hepatitis recurrence, one because of an early postoperative death and nine because of hepatitis C virus infection acquired before or after liver transplantation. In the remaining 15 patients, who were free of hepatitis C virus infection, 5-year patient and graft survivals were 100% and 87%, respectively. Despite triple immunosuppressive therapy, three patients (20%) developed chronic hepatitis with histological and serological features of autoimmune hepatitis in the absence of any other identifiable cause. The disease was severe in two patients, leading to graft failure and asymptomatic in another, despite marked histological abnormalities. In one of these three patients, autoimmune hepatitis recurred on the second liver graft as well. CONCLUSIONS: Patients undergoing liver transplantation for autoimmune hepatitis have an excellent survival rate although severe primary disease may recur, suggesting the need for stronger post-operative immunosuppressive therapy.