Conversion to tacrolimus after liver transplantation

We have reviewed our experience with conversion to tacrolimus after 435 liver transplantations. Tacrolimus was administered as a rescue agent in 33 patients until October 1993. Indications for rescue therapy were: cholestatic forms of severe, steroid-resistant cellular rejection (n=8), OKT3-resistant cellular rejections (n=6), cellular rejections in patients suffering from cyclosporin malabsorption (n=4), late onset cellular rejections (n=4), early chronic rejections (n=3), and chronic vascular or ductopenic rejections (n=8). Response was evident in 29 of the 33 patients (88%), whereas 4 patients (12%) were nonresponsive. Patient and graft survival were 76% and 70%, respecitively. Graft loss with or without patient death occurred in three of eight patients suffering from severe, steroid-resistant cellular rejection, in two of six patients with OKT3-resistant cellular rejections, and in five of eight patients undergoing chronic rejection. In severe steroid-resistant cellular rejection, successful tacrolimus rescue therapy corresponded to a significantly lower total serum bilirubin than unsuccessful therapy (12.0±5.6 mg% vs 29.7±5.9 mg%, P(0.05). We conclude that tacrolimus rescue therapy is a safe and efficient alternative for high-risk cases that do not respond to conservative treatment. In severe, steroid-resistant cellular rejection and in chronic ductopenic rejection, conversion to tacrolimus is beneficial only in a limited number of cases. A predictive parameter, which total serum bilirubin may prove to be in severe, steroid-resistant cellular rejection, is needed to select those cases that might benefit more from retransplantation than from conversion to tacrolimus.     

Chronic rejection in renal transplantation

With renal transplantation, chronic rejection is currently the most prevalent cause of late transplant failure. Clinically, chronic rejection presents as chronic transplant dysfunction, characterized by a slow loss of function, often in combination with hypertension and proteinuria. Transplant glomerulopathy and multilayering of the peritubular capillaries are highly characteristic for chronic rejection. Risk factors have been identified and include young recipient age, black race, presensitization, histoincompatibility, and acute rejection episodes, especially vascular rejection episodes and rejections that occur late after transplantation. Chronic rejection develops in grafts that undergo intermittent or persistent damage from cellular and humoral immune responses resulting from indirect recognition of alloantigens. Progression factors such as advanced donor age, renal dysfunction, hypertension, proteinuria, hyperlipidemia, and smoking play an important role. At the tissue level, senescence conditioned by ischemia/reperfusion may contribute to the development of chronic rejection. The most effective option to prevent renal failure from chronic rejection is to avoid graft injury from both immune and nonimmune mechanism together with nonnephrotoxic maintenance immunosuppression.     

The influence of late acute rejection episodes on long-term graft outcome after liver transplantation

Acute cellular rejection represents the most important single risk factor for the occurrence of chronic rejection after organ transplantation. We correlated late acute rejections with the occurrence of chronic graft failure after liver transplantation. We followed 1426 liver transplants for late acute rejection episodes defined as occurring >3 months after OLT. The overall incidence of chronic rejection in our patient population was 3.7%. In summary, we observed a predictive increase of transaminase levels prior to routine biopsies among patients with histologic evidence of late acute rejections. In contrast to other organ systems, late acute rejection episodes were not associated with the occurrence of chronic graft deterioration in liver grafts.     

Changes in liver graft rejections over time

Incidence and possible risk factors of acute rejection, time to acute rejection, graft rejection within 3 months, multiple rejections within 1 year, steroid-resistant rejection, and graft lost to chronic rejection or to chronic dysfunction were evaluated in 388 liver transplantations. HLA matches, anti-HLA class I antibodies, positive crossmatch test, or positive cytomegalovirus serology did not have an effect on the occurrence of acute or chronic rejection. Increased total bleeding diminished occurrence of acute rejection, lengthened the time to acute rejection, and reduced the risk of steroid-resistant rejection. Immunological pretransplant factors did not have a major effect on the occurrence of rejection after liver transplantation. Different types of rejections diminished over time and the time period to the first acute rejection increased, although the basic immunosuppression stayed mainly the same over 20 years in our center.     

Acute graft rejection in the late survivors of renal transplantation. Clinical and histological observations in the second decade

The clinical and histological spectrum of renal allograft rejection occurring in the early posttransplant period is well described, but there is not much information with regard to the nature of graft rejection occurring in the long-term survivors of renal transplantation. In this study, we analyzed the incidence, clinical and histological data, and outcome of graft rejection in 69 patients who survived with a functioning kidney for 10 years or longer. In this second decade, during a mean follow-up of 3 years (0.1-9.7 years), 15 patients (22%) developed 20 late rejections. Two of them received living-donor transplants and 13 received cadaver kidneys. Only 8 of these rejections (40%) were associated with abnormal clinical findings; the other 12 (60%) were asymptomatic and were detected on the basis of an unexplained deterioration in graft function. The diagnosis was made on clinical grounds in 10 cases and the other 10 were confirmed by renal histology: acute cellular rejection 1, acute cellular rejection superimposed on chronic rejection 4, and chronic rejection only 5. Thirteen acute rejections in 8 patients were treated with high-dose steroids. Of these, 6 (46%) responded fully, 4 (31%) responded partially, and 3 (23%) did not respond. Seven patients with chronic rejection were not treated. Of these, 5 have returned to dialysis within a mean period of 8 months and one patient died of hepatic failure. Our data suggest that acute reversible graft rejections can occur even after 10 years following renal transplantation. It is therefore essential to continue the maintenance immunosuppressive therapy and monitor the clinical and renal functional data at regular intervals in long-term survivors of renal transplantation.     

The yin and yang of B cells in graft rejection and tolerance

Various lineages of B cells are being increasingly recognized as important players in the etiology and prognosis of both acute and chronic graft rejection. The role of immature, chronically activated B cells, as efficient antigen-presenting cells, supporting recalcitrant cell-mediated graft rejection and late lineage B cells driving humoral rejections, is being increasingly recognized. This review captures the recent literature on this subject and discusses the various roles of the B cell in renal graft rejection and conversely, also in graft tolerance, both in animal and human studies. In addition, novel therapies targeting specific B-cell lineages in graft rejection are also discussed, with a view to developing more targeted therapies for graft rejection.     

Safe transplantation of blood type A2 livers to blood type O recipients

BACKGROUND: Transplantation of blood type A subgroup 2 (A2) livers into non-A recipients has not been reported previously. A2 to O renal transplantation has been reported, with early results including some accelerated rejections and graft losses. This has led some to selectively offer A2 renal transplantation only for patients with low anti-A titers. Given the different clinical behavior of liver allografts to preformed antibody, we felt that such restriction was unnecessary. METHODS: We performed six cases of A2 to O liver transplantation with no augmented immunomodulation or restriction with regard to antibody titers. Clinical courses, anti-A titers, rejection rates, and graft and patient survival were evaluated. RESULTS: All six patients had high pretransplant anti-A titers (>1:8), and all six grafts functioned normally. There were nine rejections in the six patients, of which three were severe (steroid-resistant) and five were late (>90 days). No rejection was vascular, and no grafts were lost, with mean follow-up of 665 days. In one patient who had anti-A antibody measured at the time of rejection IGM titers increased from baseline. Currently all patients are home with normal function. CONCLUSIONS: We found that transplantation of blood group A2 livers into blood group O recipients is safe and can be performed without graft loss and without regard to anti-A titer level. The rate of acute cellular rejection is high in this small series, and a significant proportion of these events were late or required OKT-3. We did not rely on plasmapheresis or anti-A titer determinations. However, the potential for late rejection prompts us to consider the addition of a third immunosuppressive agent. The transplantation of A2 livers into O recipients can partially compensate for the more frequent use of O livers in recipients from other blood groups.     

Reduction in acute rejections decreases chronic rejection graft failure in children: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS).

Chronic rejection accounted for 32% of all graft losses in 7123 pediatric transplants. In a previous study acute, multiple acute and late acute rejections were risk factors for the development of chronic rejection. We postulated that the recent decrease in acute rejections would translate into a lower risk for chronic rejection among patients with recent transplants. We reviewed our data on patients transplanted from 1995 to 2000, and using multivariate analysis and a proportional hazards model developed risk factors for patients whose grafts had failed due to chronic rejection. A late initial rejection increased the risk of chronic rejection graft failure 3.6-fold (p < 0.001), while a second rejection resulted in further increase of 4.2-fold (p < 0.001). Recipients who received less than 5 mg/kg of cyclosporine at 30 days post-transplant had a relative risk (RR) of 1.9 (p = 0.02). Patients transplanted from 1995 to 2000 had a significantly lower risk (RR = 0.54, p < 0.001) of graft failure from chronic rejection than those who received their transplants earlier (1987-94). Since we were able to demonstrate that there is a decreased risk of chronic rejection graft failure in our study cohort, we would conclude that the goal of future transplants should be to minimize acute rejections.     

Corneal transplantation]

In contrast to organ transplantations corneal grafts are tissue transplantations with the advantage of a minority of immune stimulating cells. The incidence of allograft rejections is greater in penetrating grafts than in lamellar grafts because of endothelial immune reactions. The decompensation of the graft is caused by the damage of the endothelial layer. The influence of HLA-A, -B and -DR matching is proven in case of vascularised cornea or of repeated perforating keratoplasty. The introduction of the immunosuppressive therapy with Ciclosporin A was successful in maintaining a clear graft.     

Acute renal allograft rejections with major interstitial oedema and plasma cell-rich infiltrates: high gamma-interferon expression and poor clinical outcome.

BACKGROUND: Acute rejections are scored according to three main criteria: vasculitis, tubulitis and interstitial infiltration as defined in the Banff classification. Typically, B cells account for <8% of the infiltrates and oedema is limited. The clinical significance of severe interstitial oedema and plasma cell-rich infiltrates (OPcR) are still a matter of debate. METHODS: Kidney graft biopsies performed between 1991 and 1998 were retrospectively evaluated for these two criteria. RESULTS: Among the 826 biopsies performed during the study period, 14 samples in 12 patients met these criteria; 11 were of Banff type I acute rejection and three were borderline. Based on clinical data, all were treated as acute rejections. OPcR occurred at a median of 187 days post-transplantation. All episodes were steroid resistant. Graft survival was 40% at 1 year following the rejection. Circulating antibodies reactive either to donor HLA or to endothelial cells were present in eight of 12 patients and widespread C4d deposit in peritubular capillary were present in three out of five patients studied. Level of gamma-interferon mRNA within the graft was significantly higher than in standard acute cellular rejection (ACR). CONCLUSION: This study showed that OPcR rejections portend a poor outcome irrespective of the Banff score. Our data strongly support the hypothesis that a humoral component participated in the graft injuries. Altogether, the data suggest that OPcR rejection might represent a late and attenuated variant of acute humoral rejection that should be classified separately from ACR.     

Pediatric renal transplantation without steroids

Pediatric renal transplant patients present a number of challenges and problems, especially the inhibited post-transplant growth seen in children receiving standard immunosuppressive triple therapy that includes steroids. We report the successful use of steroid-free immunosuppression since 1990 in 14 pediatric renal allograft recipients who received a 10-day initial course of antilymphocyte globulin and surface area-adjusted doses of cyclosporine, 7 of whom also received mycophenolate mofetil (MMF) as maintenance immunosuppression. Only 1 patient died (3 months after transplantation as a result of a primary Epstein-Barr virus infection-induced lymphoproliferative disorder), 1 patient’s graft never functioned, and another patient lost his graft after 3 years because of chronic rejection. Three patients experienced early acute cellular rejection, which resolved in 2 cases with OKT3, and in the 3rd with MMF. There were no late acute rejections. All patients evidenced growth and a growth spurt under this regimen. We conclude that all the pediatric patients benefited from our steroid-free protocol and that this protocol is superior to conventional triple therapies, which entail the eventual reduction and discontinuation of steroids, a procedure that not only inhibits growth but also carries an additional risk of acute rejection due to a steroid-adapted immune response. Received April 16, 1997; received in revised form September 8, 1997; accepted September 10, 1997     

Tacrolimus combined with mycophenolate mofetil can effectively reverse C4d-positive steroid-resistant acute rejection in Chinese renal allograft recipients.

BACKGROUND: Tacrolimus (TAC) combined with mycophenolate mofetil (MMF) has been suggested to play a critical role in the reversal of C4d-positive acute humoral rejection (AHR) in renal transplantation, but the efficacy of using only TAC-MMF without immunoadsorption or plasmapheresis has not been investigated. On the other hand, Chinese recipients of renal grafts usually need lower doses of immunosuppressants, and their optimal treatment for acute humoral rejection has not been established. METHODS: Since 1999, we have used TAC-MMF to treat steroid-resistant acute rejection (AR). C4d staining was retrospectively performed in 32 patients with steroid-resistant AR, and the treatments of 19 patients with C4d-positive steroid-resistant AR were investigated. RESULTS: Thirteen of 19 patients received TAC-MMF treatment only; 11 episodes of rejection in them were reversed (7 completely, 4 partially) and only 2 recipients lost their graft. Another 6 patients received immunoadsorption also. One of them failed to respond and lost her graft. Four of 5 patients treated with immunoadsorption and TAC-MMF recovered (3 completely, 1 partially), but 3 of them had severe pneumonia, a complication rate statistically higher than in patients treated with only TAC-MMF (P<0.05). AR occurring during the first two weeks after transplantation had a statistically better outcome than that occurring later (P = 0.003). CONCLUSION: Our study suggests that the combination of TAC and MMF is a potentially safe and economic treatment for most Chinese renal allograft recipients with C4d-positive steroid-resistant AR, especially for rejections developing within the first two weeks after transplantation.     

Natural killer cells and lung transplantation, roles in rejection, infection, and tolerance

Despite improvements in surgical technique, organ preservation, immunosuppression, and management of infection, the long term survival following lung transplantation remains low, mainly due to immune mediated complications such as acute and chronic rejection. Almost all immunosuppressive agents used in the prophylaxis and treatment of rejection following lung transplantation are targets of T cell maturation, function or proliferation, which in theory should cause sufficient disruption of the adaptive immune system to prevent graft rejection. However the five year survival rate of only 50% suggests this is not the case. More recent evidence suggests that NK cells may play a significant role in immune processes following lung transplantation. This article reviews the literature on the potential function of NK cells in rejection, infection, malignancy and tolerance following lung transplantation.     

Mycophenolatemofetil for immunosuppression after liver transplantation: a follow-up study of 191 patients

BACKGROUND: Mycophenolatemofetil (MMF) combined with calcineurin inhibitors (CNIs) as immunosuppression after orthotopic liver transplantation (OLT) is still under discussion. We retrospectively investigated the immunosuppressive potency of MMF for treatment of steroid-resistant acute rejection (AR) or chronic rejection (CR), chronic graft dysfunction, and CNI-induced toxicity in patients after OLT. METHODS: Between 1988 and 2001 we performed 1386 OLTs in 1258 patients. Since 1995, 191 patients have received MMF after OLT for steroid-resistant AR or CR, chronic graft dysfunction (115 patients), and CNI-induced toxicity (76 patients). The mean follow-up time was 56 months. RESULTS: Of 47 patients with steroid-resistant AR, 12 had been treated with OKT3, without resolving the rejection. Overall, bilirubin and transaminases decreased significantly within 2 weeks after the addition of MMF, and liver function normalized in 38 patients. Five of eight patients with CR demonstrated stable liver function after a follow-up of 55+/-8 months; 52 of 60 patients with chronic graft dysfunction improved within 3 months; and 46 of 59 patients with CNI-induced nephrotoxicity improved after MMF treatment and a reduction of CNIs (with a significant decrease in serum creatinine within 2 weeks and an increase of creatinine clearance within 3 months). Clinical symptoms improved in 10 of 12 patients with neurotoxicity and four of five patients with hepatotoxicity. Side effects of MMF, such as gastrointestinal disorders or bone marrow toxicity, occurred in 60 patients (31.4%). The incidence of infections did not increase. Patient survival was 93%, and graft survival was 88.2%. CONCLUSIONS: MMF is a potent and safe immunosuppressive agent in OLT recipients for rescue therapy in AR, CR, or chronic graft dysfunction and helps to reduce the serious toxic side effects of CNIs.     

Studies on the mechanism of chronic graft rejection in mice

Acute and chronic types of rejection after transplantation are distinguished. The exact mechanism, however, by which the different types of rejections have been brought about are not clarified. In this study, experimental data are presented on some characteristics of the chronic type of graft rejection. Allografting was performed between isogeneic mouse strains differing at their strong histocompatibility antigens. Recipients were treated with antithymocyte serum (ATS). Those recipients which showed a chronic type of graft rejection were selected and regrafted with a second-set or a third party allograft. It was found that, in most cases, the chronic rejection of first-set allografts did not results in a sensitization (= accelerated rejection), but rather in a partial specific tolerance (= prolonged graft survival) to a second-set allograft. Furthermore, transfer of spleen cells from mice of chronic rejection into normal, adult, ATS-treated, allografted mice did not result in any significant change of the mean graft survival as compared to mice not receiving spleen cell transfer. On the other hand, transfer of spleen cells from mice with acutely rejected grafts resulted in a shortened graft survival. It is supposed that the partial specific tolerance observed after chronic graft rejection may be maintained rather by a specific suppressor mechanism than clonal deletion.     

Midterm results of a prospective randomized comparison of two different rabbit-antithymocyte globulin induction therapies after heart transplantation

This prospective randomized study compared the effects in heart transplant recipients of thymoglobulin and ATG, two rabbit polyclonal antithymocyte antibodies available for induction therapy. Among 40 patients (29 men and 11 women, mean age: 40.7 +/- 14 years) undergoing orthotopic heart transplantation, 20 were randomly allocated to receive induction with thymoglobulin (group A) and 20 to ATG-fresenius (group B). Comparisons between the two groups included early posttransplant (6 months) incidence of acute rejection episodes (grade >/= 1B), bouts of steroid-resistant rejection, time to first rejection, survival, graft atherosclerosis, infections, and malignancies. The study groups displayed similar preoperative and demographic variables. No significant difference was found with regard to actuarial survival (P =.98), freedom from rejection (P =.68), number of early rejections > 1B (P =.67), mean time to first early cardiac rejection (P =.13), number of steroid-resistant rejections (P =.69). Cytomegalovirus reactivations were more frequent among group A (65%) than group B (30%; P =.028). New infections due to cytomegalovirus occurred only in group A (four patients; 20%; P =.05). No cases of malignancies were observed at a mean follow-up of 32.8 +/- 8.9 months. Although thymoglobulin and ATG showed equivalent efficacy for rejection prevention, they have different immunological properties. In particular, thymoglobulin seems to be associated with a significantly higher incidence of cytomegalovirus disease/reactivation.     

Kidney transplantation in Macedonia

During the last 10 years we performed 92 renal transplantations in our Skopje hospital (Macedonia), using 22 cadaver donors and 70 living donors. We also performed 15 explanations from cadavers and seven kidneys were allocated to former Yugoslavia. Standard surgical procedures were used for both living and cadaver donor explantations and transplantations. For living explantations, donors were matching in 66 cases (94.28%) and in four cases (5.7%) non-matching donors who however were relatives of the patient Explantations and transplantations took place only after all ethical- and legal-related problems had been solved. The minimum acceptable HLA mismatch was 50% with negative present or historical cross-match. A quadruple sequential immunosuppressive treatment was used, including either poly- or monoclonal globulins (thymoglobulin [ATG], lymphoglobulin [ALG], daclizumab, OKT-3) as an induction therapy and prednisolone, azathriopin and cyclosporin A as maintenance therapy. Rejection episodes were treated by pulse MP therapy or OKT-3 and increased doses of MMF if the patients were steroid-resistant. Kaplan-Meier survival curves showed that survival at 12, 36 and 60 month reached 90%, 75% and 60%, respectively. Survival was better after transplantation using a graft from a living donor than after transplantation using a graft from a cadaver donor (survival rates: 92%, 82% and 68% at 12, 36 and 60 months after surgery). Delayed graft functioning (DGF) was observed in 16 patients (17.3%), reaching 46.6% after transplantation of a graft from a cadaver donor and 10% after transplantation of a graft from a living donor. The relatively high percentage of DGF in the living donor program was due to the use of grafts from elderly donors (over 65 years of age). We registered 26 (29%) episodes of acute rejection that were predominantly histologically confirmed and further classified according to the BANFF criteria. Treatment of five steroid-resistant rejections proved to be successful. Neither early nor late surgical and medical complications were different from those reported in the literature. Despite the modest number of kidney transplantations, chronic renal failure has decreased in our region. The authors expect further improvement in this powerful therapeutic procedure thanks to links with regional and European transplant centers allowing better cooperation and organ sharing.     

Chronic rejection in renal transplantation

Chronic rejection in renal transplantation is an alloantigen-dependent immune process ultimately leading to graft failure. We reviewed the literature on the basis of the case history of a patient who lost her renal allograft apparently from chronic interstitial rejection. Chronic rejection presents clinically as chronic transplant dysfunction starting at various intervals after transplantation. The histopathologic features consist of chronic allograft nephropathy with or without transplant vasculopathy or glomerulopathy. Chronic rejection should be differentiated from chronic toxicity of calcineurin inhibitors, de novo or recurrent glomerulonephritis, polyoma (BK) virus nephropathy, transplant renal artery stenosis, and nephrosclerosis. Young recipient age, black race, presensitization, histoincompatibility, and acute, especially vascular, and late acute rejection episodes are dominant risk factors, compatible with immunologic mechanisms. Cellular and humoral responses resulting from indirect recognition of alloantigens with subsequent fibrotic sequelae play a central role in the pathogenesis. Circulating donor-specific antibodies and staining for C4d can detect humoral chronic rejection. The prognosis depends on alloreactivity and the presence of progression factors such as old donor age, renal dysfunction, proteinuria, hyperlipidemia, and smoking. A multifactorial approach directed to the risk and progression factors is needed to prevent premature graft loss from chronic rejection.     

Susceptibility of Liver Allografts to High or Low Concentrations of Preformed Antibodies as Measured by Flow Cytometry

Liver grafts are more resistant to damage by HLA antibodies than other organ allografts, but it is not clear if the antibodies are associated with graft rejection or graft loss, or if different antibody concentrations have different effects. To explore potential associations between antibody concentrations and outcome, preformed IgG antibodies against donor cells were quantified by flow cytometry in 465 consecutive liver transplant recipients. Antibody-positive patients were classified according to whether they had high or low antibody concentrations and analyzed for possible correlation with graft rejection or graft loss. The results showed that the incidence of rejection was not significantly different between antibody-positive and negative patients. However, patients with high antibody concentrations had a higher incidence of steroid-resistant rejections (31% at 1 year) than patients with low antibody (4%) or no antibody (8%, p < 0.0004). These effects were mainly due to T-cell (HLA class 1) antibodies. The overall incidence of rejection at 1 year was 69% for high antibody patients, 51% for patients with low antibodies and 53% for patients with no antibodies (p not significant). In an apparent paradox, antibody-positive patients underwent fewer early graft losses. Thus, the associations of preformed antibodies and outcome depend, on the one hand, on antibody concentrations, and on the other hand on whether the outcome measured is steroid-sensitive rejection, steroid-resistant rejection or graft survival. These complex interactions may explain the controversial results observed in previous studies.     

Detection of alloantibodies against non-HLA antigens in kidney transplantation by flow cytometry

The presence of alloantibodies against human leucocyte antigen (HLA)-I and HLA-II antigens has been associated with hyperacute and accelerated graft rejections. However, occasionally these rejections occur in patients without donor-specific anti-HLA antibodies, suggesting the presence of other antigenic complexes that are shared by the graft and other cell populations. Usually, these antibodies are not routinely studied and their role in graft rejection is poorly understood. For this reason, we tested, by flow cytometry, the presence of panel-reactive alloantibodies (PRA) using different cell populations in 30 pre-transplant sera of kidney graft recipients. The patients studied had or had not hyperacute and accelerated rejection episodes (HARE) and did not have alloantibodies against HLA of their specific donors. We found that IgG and IgM alloantibodies directed against HLA-I antigens, different to the HLA-I antigens of the specific donors, as well as IgG against endothelium/monocyte antigens, IgM against platelets, and IgM against T cells are significantly associated with HARE, independently of the percentage of PRA. Our findings suggest that the detection of antibodies by flow cytometry against non-major histocompatibilty complex antigens may be useful as a pre-transplant crossmatch in living related donor kidney transplants to diminish the incidence of HARE.