Increased rate of renal transplant failure in patients with the G20210A mutation of the prothrombin gene

In patients with thrombophilia caused by reduced physiological anticoagulation, renal transplant failure occurs more frequently. Previous studies showed the importance of the protein C system, a physiological anticoagulatory pathway that inhibits thrombus formation. However, excess activation of the hemostatic system also may result in thrombosis. The G20210A mutation in the prothrombin gene is such a prothrombotic risk factor that results in increased thrombus formation because of elevated factor II levels in plasma. We analyzed graft function in 270 consecutive patients who received 311 renal transplants. The presence of a normal or mutated prothrombin allele was determined by polymerase chain reaction amplification and restriction fragment length polymorphism analysis of genomic DNA. Demographic data were extracted from hospital records. Graft survival was calculated for patients with and without the G20210A mutation. We identified 9 patients heterozygous for the G20210A mutation in the prothrombin gene who had received a total of 12 renal transplants. Of these 12 transplants, 2 grafts were lost within the first year. Median graft survival for patients heterozygous for the 20210A allele was 65.9 months (range, 0 to 101 months) compared with 149 months (range, 0 to 237 months) for patients homozygous for the normal 20210 G allele (P = 0.02). The G20210A mutation represented a 2.95-fold (95% confidence interval, 1.03 to 8.46) increase in risk for graft loss. Only 1 patient with this mutation achieved graft function exceeding 101 months. The G20210A mutation of the prothrombin gene is an independent risk factor for graft failure.

CC chemokine receptor 5 and renal-transplant survival

BACKGROUND

About 1% of white populations are homozygous carriers of an allele of the gene for the CC chemokine receptor 5 (CCR5) with a 32 bp deletion (CCR5Delta32), which leads to an inactive receptor. During acute and chronic transplant rejection, ligands for CCR5 are upregulated, and the graft is infiltrated by CCR5-positive mononuclear cells. We therefore investigated the influence of CCR5Delta32 on renal-transplant survival.

METHODS

Genomic DNA from peripheral-blood leucocytes of 1227 renal-transplant recipients was screened by PCR for the presence of CCR5Delta32. Demographic and clinical data were extracted from hospital records. Complete follow-up data were available for 576 recipients of first renal transplants. Graft survival was analysed by Fisher's exact test and Kaplan-Meier plots compared with a log-rank test.

FINDINGS

PCR identified 21 patients homozygous for CCR5Delta32 (frequency 1.7%). One patient died with a functioning graft. Only one of the remaining patients lost transplant function during follow-up (median 7.2 years) compared with 78 of the 555 patients with a homozygous wild-type or heterozygous CCR5Delta32 genotype. Graft survival was significantly longer in the homozygous CCR5Delta32 group than in the control group (log-rank p=0.033; hazard ratio 0.367 [95% CI 0.157-0.859]).

INTERPRETATION

Patients homozygous for CCR5Delta32 show longer survival of renal transplants than those with other genotypes, suggesting a pathophysiological role for CCR5 in transplant loss. This receptor may be a useful target for the prevention of transplant loss.

Hyperimmunoglobulin prophylaxis, monitoring and preemptive ganciclovir treatment eliminate the risk of CMV infection to improve patient and renal allograft survival

This study was designed to investigate whether the introduction of ganciclovir to clinical use for anti-CMV treatment changes the risk of CMV infection in renal transplant patients. A total of 1545 cases who had received cadaveric renal transplants were divided into two groups: group 1 (n = 721) was made up of patients who received their transplants within 6 years before the introduction (1991) of ganciclovir and group 2 (n = 824), of individuals transplanted thereafter. Patient and graft survival of CMV D+/R- patients was uni- and multivariately compared with non-CMV D+/R- patients. In CMV D+/R- patients in group 1, survival was significantly lower, and their relative risk for graft loss was 1.32-fold (P = 0.0483) that of non-CMV D+/R- patients. In group 2 patient and graft survival was identical regardless of whether the patients were at risk for CMV infection or not. The risk of CMV infection can be eliminated by hyperimmunoglobulin prophylaxis, CMV monitoring and preemptive ganciclovir treatment in renal transplant patients.

Positive donor and negative recipient cytomegalovirus status is a detrimental factor for long-term renal allograft survival

In 524 allogeneic cadaveric kidney transplants, the impact of cytomegalovirus (CMV) donor/recipient status on the incidence of CMV infection, CMV disease, early and long-term graft, and patient survival have been analyzed with respect to rejection episodes. Most CMV infections (59%) and diseases (17%) were found in CMV-negative recipients of CMV-positive kidneys. The 1-year function rate of CMV-positive kidneys (75%) dropped about 10% below that of CMV-negative organs (85%), and in the case of CMV-negative recipients an additional graft loss of more than 10% happened within the 4th and 5th years (5-year graft survival pos./neg.: 56%). This detrimental effect was exaggerated if it coincided with antibody-treated rejection episodes.

Impact of humoral alloreactivity early after transplantation on the long-term survival of renal allografts

BACKGROUND

The contribution of humoral alloreactivity to the rejection of renal allografts is not well defined because humoral antigraft reactions are not easily detectable in transplant biopsies, and serial measurements of circulating allo-antibodies in the post-transplantation period are not routinely performed. We have developed diagnostic techniques that improve the assessment of humoral alloreactivity in vivo and in vitro.

METHODS

Humoral alloreactivity in transplant biopsies derived from 218 single kidney grafts was detected by assessing the deposition of complement fragment C4d in interstitial capillaries. Circulating alloantibodies were determined in corresponding serum samples by flow cytometry using lymphoblastoid cell lines of donor DR-type as target cells and by a conventional microcytotoxicity test. The impact of capillary C4d and other selected variables on renal graft survival was calculated by univariate and multivariate analysis.

RESULTS

Capillary C4d, present in 46% of biopsies from first grafts and 72% of regrafts, is related to circulating alloantibodies. Grafts with capillary C4d have a markedly shorter survival than grafts without capillary C4d (50% graft survival, 4 vs. 8 years, P = 0.0001). Among several risk factors, capillary C4d is the strongest predictor of subsequent graft loss in a multivariate analysis (relative risk, 2.1, 95% CI, 1.4 to 3.1). Humoral alloreactivity detectable within six months after transplantation has a much stronger impact on graft survival than alloreactivity detected beyond this period.

CONCLUSIONS

Humoral alloreactivity, manifested by the capillary deposition of complement C4d in about 50% of biopsied renal grafts, exerts a strong impact on graft survival when it operates within six months after transplantation.

Aggressive treatment of the first acute rejection episode using first-line anti-lymphocytic preparation reduces further acute rejection episodes after human kidney transplantation

The detrimental effect of acute rejection episodes on long-term outcome of renal allografts in cyclosporin-treated patients is well established, although has not been seen by all investigators. To analyse the possibility that aggressive treatment of the first episode may ameliorate this detrimental effect, we performed an open label, randomised prospective trial in cyclosporin-based, immunosuppressed recipients of postmortem renal allografts in order to compare two different treatment protocols during primary acute rejection episodes: (1) group 1 of 25 patients received 3 x 250 mg methylprednisolone (MP) i.v.; (2) group 2 of 25 patients received 7 x anti-thymocyte globulin (ATG)-Fresenius i.v. (4 mg/kg body weight). During a period of 4 years, the following clinical observations were made: (1) The incidence of an acute re-rejection episode was significantly reduced in the ATG-treated study group (16%) compared to the MP-treated study group (72%); (2) The severity of the first acute rejection episode (intensity of renal dysfunction measured in terms of 10-day creatinine area under curve) showed no significant difference between the groups (37 mg x 10-d/dl to 58 mg x 10-d/dl); and (3) The half-lives of allografts in both groups have not shown any significant differences so far. In conclusion, aggressive treatment of the first rejection episode of renal allografts with the use of ATG reduced the incidence of re-rejection episodes which, however, are not reflected so far by improvement of the 4-year survival rate of these allografts. Since it could be observed that re-rejection is an even worse predictor for chronic transplant failure, a better long-term outcome of renal allografts in ATG-treated patients may be expected during a longer observation period. The incidence of a third episode was also reduced in the ATG-treated group (0%) compared to the MP-treated group (12%).

Mycophenolate mofetil-based, cyclosporine-free induction and maintenance immunosuppression: first-3-months analysis of efficacy and safety in two cohorts of renal allograft recipients

BACKGROUND

The currently used macrolide immunosuppressants, i.e., cyclosporine and tacrolimus, exert considerable nephrotoxicity. We aimed to avoid the nephrotoxic effects by applying a cyclosporine-free regimen for the induction as well as for the maintenance treatment of renal allograft recipients using mycophenolate mofetil (MMF) as the primary immunosuppressant.

METHODS

Thirteen patients were converted from cyclosporine (CsA) to MMF monotherapy. For 4 weeks, MMF (2 g/day) was added to the CsA treatment, before CsA was tapered by weekly steps of 25 mg/day and without "safeguard treatment" with additional immunosuppressants. In a second approach, 12 patients older than 50 years, and receiving a renal graft from a donor older than 50 years, were treated primarily with MMF combined with steroids and an induction therapy using antithymocyte globulin, and without the addition of CsA.

RESULTS

Thirteen long-term renal transplant patients could be converted from CsA to MMF monotherapy. Conversion resulted in an immediate and long-lasting improvement of their median creatinine values by 20%. No serious adverse events occurred. In the second cohort of 12 patients, MMF was used as the primary immunosuppressant. All patients are alive and no grafts were lost after 4 months (n= 12) and after 6 months (n=7). The median creatinine values achieved after 4 and 6 months were 1.16+/-0.25 and 1.30+/-0.21 mg/dl, respectively. One patient was converted to CsA because of a reversible rejection episode (8.3%), and another patient was converted because of cytomegalovirus disease. Major complications consisted of wound-healing disturbances (16.6%) and cytomegalovirus infections (41.6%).

CONCLUSION

MMF monotherapy can be safely applied as long-term maintenance immunosuppression with improvement of renal function. Steroids are not required as an adjunct to MMF. MMF monotherapy, in the absence of drug-related nephrotoxicity, is particularly beneficial for grafts derived from marginal donors, such as donors of advanced age.

[Bladder drainage in pancreas transplantation--results of a consecutive series of 100 transplantations]

Simultaneous pancreas/kidney transplantation has become a therapeutic approach for patients with renal failure resulting from type-I diabetes mellitus. However, the appropriate route for drainage of the exocrine secretions of the pancreatic gland remains unclear. While bladder drainage is the current state of the art, it is associated with a high frequency of urologic complications like urinary tract infections, hematuria, metabolic acidosis, and reflux pancreatitis.

Early loss of renal transplants in patients with thrombophilia

BACKGROUND

We considered the possibility that thrombophilia may propagate graft thrombosis and therefore we evaluated the protein C system, which is a natural anticoagulant. Potential alterations in this system include protein C or protein S deficiency, inhibition through a lupus anticoagulant (LA), or a resistance to activated protein C due to the factor V Leiden (FVL) mutation.

METHODS

One hundred thirty-two consecutive renal transplant patients, not known to have abnormal thrombostasis, in whom 1-year graft survival could be assessed, underwent laboratory testing for protein C or S activity, LA, and FVL. Transplant survival and demographic data were extracted from the hospital record.

RESULTS

We identified 18 patients with thrombophilia (FVL, 10; LA, 6; protein S, 2) who had received a total of 28 renal transplants. Of these 28 transplant recipients, 11 transplants were lost within the first year, compared with 21 of 155 transplants to 114 patients without thrombophilia (P=0.0003). Median graft survival for patients with thrombophilia was 30 months (range: 0 to 166), compared with 86 months (range: 0 to 212) for patients without thrombophilia (P<0.01). The presence of thrombophilia represented a 3.5-fold (95% confidence interval, 2.3-5.3-fold) risk for 1-year graft loss.

CONCLUSION

In this retrospective study, patients with thrombophilia had a significantly higher risk of early transplant failure. These data point toward a potential contribution of thrombophilia to transplant loss, a hypothesis that needs further study.

[Chronic transplant reaction of the kidney. A interphase cytogenetic and immunohistologic characterization of the involved cells in relation to donor and recipient origin]

Chronic rejection is a major problem in contemporary kidney transplantation. The purpose of this study was to determine whether renal cells are repopulated by extra-renal cells over time or whether the graft remains permanently allogenic. We studied nine explanted allografted kidneys of sex-mismatched donors by means of non-isotopic in situ hybridization (NISH). We used biotinylated centromer-specific DNA probes of the human chromosomes Y and X. In a further step, monoclonal and polyclonal antibodies against CD45, CD3, CD20, CD31, CD1a, S100, alpha-actin, factor Vill and UEA were used to analyse the various infiltrating cell types and the cells involved in allograft arteriopathy. In several cases NISH and immunohistochemistry were combined to facilitate the typing of cells. Our study showed that up to several years after transplantation the glomerular, tubular and endothelial cells retained donor origin. The only cells of recipient origin were the inflammatory cells, predominantly macrophages and T lymphocytes.

Early renal graft dysfunction. The role of preformed antibodies to DR-typed lymphoblastoid cell lines

Diverse pathogenetic factors may lead to the complex syndrome of early graft dysfunction, an important determinant of later renal graft outcome. That humoral factors could play a prominent role in the development of the syndrome was suggested by the capillary deposition of complement fragment C4d in about 50% of graft biopsies. This study investigates whether the presumed classical activation of complement is derived from preformed antibodies that would possibly react against endothelial HLA-class II molecules. Such antibodies were detectable by flow cytometry using a representative collection of 11 DR-typed lymphoblastoid cell lines (LCL) as targets. Simultaneous discrimination between complement-activating and -nonactivating antibodies was achieved by two-color FACS analysis. Using this method, 44 out of 86 pretransplant serum samples from recipients with early dysfunction showed reactivity against LCL (18 complement-activating, 14 nonactivating, 12 complement-activating non-IgG). Conventional panel-reactivity was observed in 20 sera only (14 also LCL-reactive). Evaluation of corresponding graft biopsies revealed that capillary C4d was associated with LCL (P = 0.018) and panel reactivity (P = 0.015) alone and in combination (P = 0.001; Pearson's chi-square test). Thirteen subsequent graft losses within one year were observed in the LCL-reactive group as compared with seven losses in the nonreactive group (panel-reactive: 7; nonreactive: 13). Thus, measurement of LCL-reactive antibodies in prospective transplant recipients improves the assessment of an individual immunological risk. The results further demonstrate that performed antibodies do not simply reflect the enhanced overall immune reactivity of certain recipients but rather act locally in vivo, thus emphasizing the role of humoral factors in the development of early graft dysfunction.

Mycophenolate mofetil in patients with acute renal failure: evidence of metabolite (MPAG) accumulation and removal by dialysis

Pharmacokinetics of mycophenolic acid (MPA) was analyzed in eight patients with post-transplant acute renal failure. Furthermore, the effect of hemodialysis upon blood levels of MPA and its major metabolite, MPA glucuronide (MPAG), was determined. The mean duration of the posttransplant renal failure was 18 days, but renal function resumed in all patients eventually. The patients were treated with 3 g/day of mycophenolate mofetil for 28 consecutive days combined with cyclosporine A, methylprednisolone, and ATG for induction therapy. In all patients, accumulation of MPAG but not of MPA was observed. MPA trough levels were in the range between 0.5 microgram/ml at day 2 and 2.3 micrograms/ml at the end of the study period. However, this concentration difference did not reach statistical significance. Trough levels of MPAG accumulated, reaching levels as high as 358 micrograms/ml. However, with increasing recovery of renal function, MPAG levels fell to a median trough concentration of 141 micrograms/ml. MPAG, but not MPA, could partially be removed from the circulation by hemodialysis treatment.

Assessment of oxygen radicals during kidney transplantation--effect of radical scavenger

In the present study, levels of free oxygen radicals, generated in the very early period of reperfusion during human kidney transplantation, were assessed by determination of malondialdehyde (MDA) levels using a high-pressure liquid chromatography (HPLC) method. Renal blood samples were obtained during reperfusion by intraoperative cannulation of the renal vein. Simultaneously, systemic MDA levels were determined. Furthermore, local and systemic levels of interleukin 6 (IL-6), tumor necrosis factor (TNF) receptors, p55 and p75, and vitamin E were measured. In a second group of patients, 500 mg of ascorbic acid were given prior to reperfusion. Renal MDA levels in the control group were always higher compared to systemic levels. IL-6 showed a marked increase shortly after reperfusion in the renal blood. In the scavenger group there was a diminution of these effects. TNF receptor levels and vitamin E remained largely unchanged. The results of this pilot study demonstrated clinically the moderate production of reactive oxygen species and the liberation of IL-6 shortly after reperfusion of human transplanted kidneys. Furthermore, the modulating effect of a radical scavenger on these effects was shown.

The beneficial effect of human recombinant superoxide dismutase on acute and chronic rejection events in recipients of cadaveric renal transplants

In a prospective randomized double-blind placebo-controlled trial, the effect of rh-SOD, given in a dose of 200 mg intravenously during surgery to cyclosporine-treated recipients of cadaveric renal allografts, on both acute and chronic rejection events as well as patient and graft survival was investigated by analyzing the patients' charts retrospectively. The results obtained show that rh-SOD exerts a beneficial effect on acute rejection events as indicated by a significant reduction of (1) first acute rejection episodes from 33.3% in controls to 18.5%, as well as (2) early irreversible acute rejection from 12.5% in controls to 3.7%. With regard to long-term results, there was a significant improvement of the actual 4-year graft survival rate in rh-SOD-treated patients to 74% (with a projected half-life of 15 years) compared with 52% in controls (with an extrapolated half-life of 5 years). The beneficial effect of rh-SOD observed in this trial is not fully understood, although one can assume that the effect is related to its antioxidant action on ischemia/reperfusion injury of the renal allograft, thereby potentially reducing the immunogenicity of the graft. In addition and in accordance with the "response-to-injury hypothesis" in the pathogenesis of general atherosclerosis, rh-SOD has the potential to mitigate free radical-mediated reperfusion injury-induced acute endothelial cell damage that potentially may contribute to the process of chronic obliterative rejection arteriosclerosis.

Capillary deposition of C4d complement fragment and early renal graft loss

Clinical outcome of kidney grafts that are affected by the complex syndrome of 'early graft dysfunction' is uncertain and rather unpredictable. In this study, an individual prognosis for dysfunctioning allografts (N = 93) is attempted by the immunohistological assessment of vascular classical complement activation in graft biopsies. Thus, capillary deposition of complement fragment C4d was observed in the majority (N = 51) of early dysfunctioning grafts. In 43 biopsies, abundant deposition of fragment C4d was present in all capillaries, whereas in eight specimens a segmental distribution of capillary C4d was observed. In 42 grafts with early dysfunction no capillary C4d was detectable. Eighteen subsequent graft losses within one year (16 early losses) were recorded in the subgroup with C4d in all capillaries, and three early losses in the group with segmentally distributed C4d. Only four graft losses (3 early losses) were recorded in the C4d-negative group (P = 0.0027; Pearson's chi square test). The resulting one-year graft survival rates (72% for the study group) differed markedly between the subgroups. Grafts with generalized or segmental capillary deposition of C4d had 57% and 63% survival, respectively, contrasted by 90% survival in the C4d-negative group. It is of note, however, that also three of the four grafts that were finally lost within the C4d-negative group, showed distinct capillary deposition of C4d in second biopsies. Vascular deposition of complement fragment C4d therefore represents a clinically relevant factor that contributes to early graft dysfunction. Its assessment is helpful for an individual graft prognosis.

Outcome of renal grafts after simultaneous kidney/pancreas transplantation

Nineteen patients with endstage renal failure due to Type 1 (insulin-dependent) diabetes mellitus received simultaneous pancreas/kidney transplants using bladder drainage technique. Another group of 25 Type 1 diabetic patients received pancreas/kidney transplants by the duct occlusion technique. We observed a higher incidence of rejection episodes in the patients of the bladder drainage group than those in the duct occlusion group, 14 of 19 patients (74%) vs 7 of 25 (28%) respectively. Anti CD3 antibodies (OrthocloneR, OKT3) as a part of induction treatment was used more often in the bladder drainage group (58%) than in the control group (20%).

Short-term effect of whole milk and milk fermented by Pseudomonas fluorescens on plasma lipids in adult boars

The short-term effects of whole milk and milk fermented by Pseudomonas fluorescens, of the amino acid composition of the diet and of feeding frequency on the level of plasma lipids, were investigated in six 1-year-old adult boars. The experimental diets contained equal amounts of protein, carbohydrates, fat and cholesterol. After an adaptation period of 5 d for each experimental treatment, blood was collected at regular intervals during 48 h and plasma levels of cholesterol, triacylglycerol, high-density-lipoprotein (HDL)-cholesterol and low-density-lipoprotein (LDL)-cholesterol were examined. All variables except HDL-cholesterol showed distinct diurnal fluctuations, which were substantially influenced by feeding frequency. Variations in the amino acid composition of the experimental diets, which were within a physiological range, had no effect on the level of plasma lipids. Plasma lipid levels were significantly lower when the animals received the diets containing milk instead of the diet without milk: cholesterol, triacylglycerol, and LDL-cholesterol were reduced by 5.6, 5.8 and 10% respectively (pondered means) while HDL-cholesterol remained unaffected. Fermentation of whole milk by P. fluorescens reduced the lipid-lowering effect. Our findings suggest that the intake of diets containing milk results in a lower plasma cholesterol and LDL-cholesterol level than the intake of diets with a similar nutrient content which do not contain milk.