Hiroshi Toma

Excellent Long‐term Outcome of ABO‐Incompatible Living Donor Kidney Transplantation in Japan

Owing to the severe shortage of cadaveric grafts in Japan, we have performed ABO‐incompatible living donor kidney transplantation since 1989. This study assessed short‐ and long‐term outcomes in 441 patients who received ABO‐incompatible living donor kidney transplants between January 1989 and December 2001. We compared our results with historical data from 1055 recipients of living kidney transplantation. Overall patient survival rates 1, 3, 5, 7, and 9 years after ABO‐incompatible transplantation were 93%, 89%, 87%, 85%, and 84%, respectively. Corresponding overall graft survival rates were 84%, 80%, 71%, 65%, and 59%. After ABO‐incompatible transplantation, graft survival rates were significantly higher in patients 29 years or younger than in those 30 years or older and in patients who received anticoagulation therapy than in those who did not receive such therapy. There were no significant differences between A‐incompatible and B‐incompatible recipients with respect to clinical outcomes. The graft survival rate at 1 year in the historical controls was slightly but not significantly higher than that in our recipients of ABO‐incompatible transplants. We conclude that long‐term outcome in recipients of ABO‐incompatible living kidneys is excellent. Transplantation of ABO‐incompatible kidneys from living donors is a radical, but effective treatment for end‐stage renal disease.

Long-term results of ABO-incompatible living kidney transplantation: a single-center experience.

Background. Despite great efforts to promote the donation of cadaveric organs, the number of organ transplantations in Japan is not increasing and a serious shortage of cadaveric organs exists. These circumstances have forced a widening of indications for kidney transplantation. For this purpose, ABO-incompatible living kidney transplantations (LKTs) have been performed. Although we have already reported the short-term results of ABO-incompatible LKT, there is no report of long-term results in such cases; anti-A and anti-B antibodies could cause antibody-induced chronic rejection and result in poor long-term graft survival. In this study, we have reviewed the long-term results of ABO-incompatible LKT and tried to identify the most important factors for long-term renal function in ABO-incompatible LKT. Methods. Sixty-seven patients with end-stage renal failure underwent ABO-incompatible living kidney transplantation at our institute between January, 1989, and December, 1995. The mean age was 34.9 years (range, 8-58 years), with 38 males and 29 females. Incompatibility in ABO blood group antigens was as follows: A1<O, 23 patients; B→O, 19 patients; A1B→A1, 7 patients; B→A1, 8 patients; A1→B; 4 patients; A1B<B, 4 patients; A1B→O, 2 patients. The number of HLA-AB, and -DR mismatches were 1.6±1.1 and 0.76±0.6, respectively. Plasmapheresis and immunoadsorption were carried out to remove the anti-AB antibodies before the kidney transplantation. In the induction phase, methylprednisolone, cyclosporine, azathioprine, antilymphocyte globulin, and deoxyspergualin were used for immunosuppression. Local irradiation of the graft was performed at a dose of 150 rad, on the first, third, and fifth days after transplantation. Splenectomy was done at the time of kidney transplantation in all cases. Results. Patient survival was 93% at 1 year and 91% at 8 years. Graft survival was 79% at 1, 2, 3, and 4 years, 75% at 5 and 6 years, and 73% at 7 and 8 years. Patient survival was not significantly different from that of ABO-compatible patients. However, graft survival was significantly different between ABO-incompatible grafts and ABO-compatible grafts. Specifically, ABO-incompatible transplant recipients experienced a significantly higher rate of early graft loss up to 3 years but showed an equivalent graft loss by year 4. Among 67 patients, 16 grafts were lost during the observation period. Loss was due to acute rejection in 5 patients, followed by chronic rejection in 5 patients and death with function in 3 patients, whereas immunosuppression was withdrawn in 3 patients due to nonimmunological reasons. Of 16 grafts lost, 15 were lost within 1 year after transplantation. Of the 67 patients, 5 died during observation. Three patients with functioning grafts died of uncontrolled bleeding due to duodenal ulcer, malignant lymphoma, and cerebral hemorrhage (one patient each). One patient died of ischemic colitis due to secondary amyloidosis and one patient of cerebral hemorrhage after graft loss due to humoral rejection. There was no fatal infectious complication, whereas 10 patients had non-tissue-invasive cytomegalovirus infection. The stepwise logistic regression model was employed to identify the most important factors for long-term renal function.

Postoperative production of anti-donor antibody and chronic rejection in renal transplantation.

To study the relevance of anti-donor antibody (ADA) to chronic rejection in kidney transplantation, we retrospectively examined the long-term kinetics of ADA by flow cytometric analysis. Among 537 recipients who underwent living-donor kidney transplantation between 1986 and 1994, 29 patients with chronic rejection (CR group) and 33 patients with stable graft function (ST group) were randomly selected for analysis. Patient serum taken 1 or 2 days before transplantation, serum taken 1 month after transplantation, and the most current serum were analyzed for the presence of ADA to donor T and B cells. In the CR group, IgG antibody to donor B cells of the most current serum was positive in 25 of 29 patients, whereas it was positive in only 5 patients in the ST group P<0.001. The mean fluorescent intensity of the antibody was also significantly higher in the CR group than that in ST group P<0.01. In contrast, IgG antibody to donor T cells of the most current serum was positive in only five patients in the CR group. No significant difference was observed in the pretransplant and 1-month posttransplant sera between the CR and ST groups. We conclude that the posttransplant production of IgG antibody to donor B cells seemed to be highly relevant to chronic rejection.

Role of anti-A/B antibody titers in results of ABO-incompatible kidney transplantation.

Background. Our previous studies showed that the incidence of humoral rejection was extremely high in ABO-incompatible living kidney transplantation. This result suggests that anti-A/B antibody titers directly influence the graft survival of ABO-incompatible kidney transplantation. In this study, we examined the impact of preoperative anti-A/B antibody titers on the results of ABO-incompatible living kidney transplantation. Methods. Sixty-seven patients underwent ABO-incompatible living kidney transplantation at our institution between January 1989 and December 1995. The mean age was 34.9 years with 38 males and 29 females. Sixty-one of the 67 recipients were included in an analysis of the impact of anti-A/B antibody titer in long-term graft survival. The remaining six patients were excluded because of death with a functioning graft (three patients) and withdrawal of immunosuppression due to nonimmunological reasons (three patients) within 1 year after renal transplantation. Results. The graft survival rate for the level of less than 1:16 in maximum IgG antibody before transplantation (n=21) at 1, 5, and 8 years was 81.0, 66.8, and 66.8%, respectively. The corresponding values for the level of 1:32–1:64 (n=33) and higher than 1:128 (n=7) were 93.9, 90.5, and 79.7%, and 42.9, 28.6, and 28.6%, respectively (log-rank test, P =0.0007). There was no significant association between maximum anti-A/B IgM titers, minimum anti-A/B IgM titers, minimum anti-A/B IgG titers, and graft survival. Conclusions. Preoperative maximum anti-A/B IgG titers correlated with the long-term graft survival in ABO-incompatible living kidney transplantation. Thus, preoperative maximum levels of anti-A/B IgG titers are one of the good predictors of the results of ABO-incompatible living kidney transplantation.

Current status of renal replacement therapy in Japan

The study of the current status of renal replacement therapy in Japan is based on the analysis of data from the registry reports for regular dialysis therapy and kidney transplantation. The total number of patients receiving regular dialysis therapy was 123,926 at the end of 1992: 117,809 (95.1%) on hemodialysis and 6,117 (4.9%) on peritoneal dialysis. The primary diseases of newly accepted patients were chronic glomerulonephritis (42.2%), diabetic nephropathy (28.4%), nephrosclerosis (5.9%), polycystic kidney disease (2.7%), chronic pyelonephritis (1.6%), and others. The number of kidney transplant patients in Japan was 8,384 at the end of 1991: 6,154 (73.4%) received a living donor transplantation and 2,230 (26.9%) received a cadaver donor transplantation. Overall 5-year survival rates of dialysis patients were 60.4%: 69.7% for chronic glomerulonephritis, 41.7% for diabetic nephropathy, 39.6% for nephrosclerosis, 73.6% for diffuse polycystic kidney disease, and 66.6% for chronic pyelonephritis. The causes of death of dialysis patients were heart failure (31.1%), cerebrovascular accident (13.6%), infectious diseases (11.3%), malignancies (7.1%), cachexia/uremia (6.7%), myocardial infarction (5.8%), and others. The gross mortality rate of dialysis patients was increased in cases of less than 4 hours of the average length of each dialysis session, less than 4% and more than 9% of the average weight loss during each dialysis session, less than 1.0 of Kt/V, and less than 0.9 and more than 1.7 g/kg/d of protein catabolic rate. Overall 5-year patient and graft survival rates of kidney transplant patients since 1964 were 82.7% and 60.3%: 84.4% and 65.0% in living donor cases, and 77.4% and 46.2% in cadaver donor case, respectively. Those since 1983 were 90.1% and 68.2%: 91.3% and 72.6% in living donor cases, and 87.8% and 59.3%, respectively. Graft survival rates were superior in cases treated with combined steroid, cyclosporine and azathioprine or mizoribine, to those treated with other immuno-suppressive regimens, and they decreased as the number of HLA-A, -B and -DR increased.

Urothelium regeneration using viable cultured urothelial cell sheets grafted on demucosalized gastric flaps.

Most of the papers in this section are studies of cellular biology in urological cancer. Each of the four papers assess a particular aspect of four different types of cancer: prostate, bladder, renal, and testicular. The other two reports are on unrelated issues; in the first, the authors write about urothelial regeneration using viable cultured urothelial cell sheets grafted onto demucosalized gastric flaps, and in the second, on the in vivo expression of nitric oxide synthase.

Induction of chemokine gene expression during allogeneic skin graft rejection

The factors mediating trafficking of alloantigen-primed T cells and mononuclear phagocytes to the site of an allograft during the graft rejection process remain largely undefined. Based upon their demonstrated chemoattractant properties, chemokines may play a role in directing inflammatory cells to graft sites and initiate rejection. To begin to investigate the role of chemokines in graft rejection, we used Northern blot analysis to examine the temporal expression of 6 chemokine genes in murine allogeneic skin grafts disparate at the entire MHC and minor antigens and grafts with a disparity at either single class I or class II MHC determinants. Two general patterns of chemokine gene expression in each of the allografts were observed. Intragraft expression of 1 group of chemokine genes, including macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, JE, and KC was observed at peak levels 3 days posttransplant in each of the 3 different allograft models. Expression of these genes in control isografts was at low levels, with the exception of JE, which was expressed at equivalent levels in all iso- and allografts for the first 4-5 days posttransplant, and KC, which was expressed at equivalent levels in C57BL/6 isografts and bm1 and bm12 allografts. A second group of chemokine genes, including RANTES (regulated upon activation normal T cell expressed and secreted) and IP-10 (interferon-gamma inducible protein), was expressed at low levels at early times after transplantation but at high levels 3-4 days before rejection of the allografts was complete. Isograft expression of RANTES and IP-10 was undetectable at the late time points. The results suggest that these 2 patterns of chemoattractant cytokine gene expression may be representative of the early inflammatory and the late T cell-mediated phases of the allograft rejection process, respectively.

Anti-AB titer changes in patients with ABO incompatibility after living related kidney transplantations: survey of 101 cases to determine whether splenectomies are necessary for successful transplantation.

Background. A shortage of organ donors for transplantation has become a serious problem throughout the world. To overcome this problem, transplantations across ABO blood barriers have been performed with some success. In general, however, the graft survival rate for transplantation with ABO incompatibility is lower than that of transplantation with ABO compatibility. Unfortunately, the mechanism by which isohemagglutinins might injure an ABO-incompatible graft remains uncertain. Here, the pre- and posttransplantation anti-AB titers in patients who received transplants from ABO-incompatible living donors are reviewed and the pathological findings are compared. Methods One hundred and one patients underwent ABO-incompatible living related kidney transplantation (i-LKT) between January 1989 and October 1999 at our hospital. Plasmapheresis and immunoadsorption were performed in all of the i-LKT patients before the transplantation to remove anti-AB antibodies. A splenectomy was also performed during the operation, followed by the local irradiation of the graft with a dose of 150 rad. The anti-AB titers and pathological findings for 93 i-LKT patients, excluding 8 patients who died, were then examined. Results Immediately after the i-LKT, the anti-AB titer dropped rapidly to below 1:4 in all 93 cases. Seventy of patients (70/93, 75%) showed no elevation in their anti-AB titer during their follow-up. However, the remaining 23 patients (23/93, 25%) showed a significant elevation of their anti-AB titer to over 1:16. Sixteen of these patients (16/93, 17%) exhibited an anti-AB titer of over 1:32. Out of these 16 patients, 11 patients (11/16, 69%) lost their grafts. The anti-AB titer in the remaining five patients (5/16, 31%) spontaneously decreased without any special treatment. Seven patients (7/93, 8%) exhibited an elevated titer of 1:16. Out of these patients, only one patient (1/7, 14%) lost his graft. The elevated titers in the remaining six patients (6/7, 86%) eventually decreased. The graft function improved in patients whose elevated anti-AB titers eventually decreased. Control patients (ABO-compatible kidney transplant patients) showed a normal elevation of their titer values compared with preoperative titers. Pathological findings showed severe humoral rejections in all cases with high anti-AB titers that lost grafts. Humoral rejection was also detected in most of the patients whose anti-AB titer was elevated to over 1:16 after the transplantation, but excellent renal function was resumed once the titers decreased to below 1:4. Conclusions In 23 out of 93 i-LKT patients (25%), the anti-AB titers were significantly elevated after the splenectomy. In view of other reports of i-LKT without splenectomy, we feel that a splenectomy in i-LKT patients might be unnecessary. Pathological evidence suggests that the decrease in the anti-AB titer after transplantation might be the net result of plasmapheresis before the operation and the adsorption of antibodies to the endothelium of the transplanted organ after the operation, neither of which is influenced by a splenectomy.

A single amino acid alteration in cytoplasmic domain determines IL-2 promoter activation by ligation of CD28 but not inducible costimulator (ICOS).

The CD28 family molecules, CD28, and inducible costimulator (ICOS) all provide positive costimulatory signals. However, unlike CD28, ICOS does not costimulate IL-2 secretion. The YMNM motif that exists in the CD28 cytoplasmic domain is a known binding site for phosphatidylinositol 3-kinase (PI3-K) and Grb2. ICOS possesses the YMFM motif in the corresponding region of CD28 that binds PI3-K but not Grb2. We postulated that the reason that ICOS does not have the ability to induce IL-2 production is because it fails to recruit Grb2. To verify this hypothesis, we generated a mutant ICOS gene that contains the CD28 YMNM motif and measured IL-2 promoter activation after ICOS ligation. The results indicated that ICOS became competent to activate the IL-2 promoter by this single alteration. Further analysis demonstrated that Grb2 binding to ICOS was sufficient to activate the NFAT/AP-1 site in the IL-2 promoter and that the cytoplasmic domain of CD28 outside of the YMNM motif is required for activation of the CD28RE/AP-1 and NF-κB sites. Together, these observations lead us to believe that the difference of a single amino acid, which affects Grb2 binding ability, may define a functional difference between the CD28- and ICOS-mediated costimulatory signals.

Transplantable Urothelial Cell Sheets Harvested Noninvasively from Temperature-Responsive Culture Surfaces by Reducing Temperature

Augmentation cystoplasty using gastrointestinal flaps may induce severe complications such as lithiasis, urinary tract infection, and electrolyte imbalance. The use of viable, contiguous urothelial cell sheets cultured in vitro should enable us to avoid these complications. Transplantable urothelial cell sheets were obtained by utilizing a temperature-responsive cell culture method, and then examined by immunostaining and electron microscopy. Canine urothelium was produced on the surfaces of temperature-responsive culture dishes covalently bonded with the thermally sensitive polymer, poly(N-isopropylacrylamide). Stratified urothelial cell sheets were cultured and then harvested intact without enzymatic treatment from these dishes by reducing the temperature. Histological structure and cell-to-cell junctions were compared between these urothelial cell sheets and those harvested with dispase. All urothelial cell sheets were harvested from the bonded surfaces by reducing the culture temperature without the need for dispase. Electron microscopy revealed well-developed microridge, microvilli, and cell junction complexes. Conversely, these same cell features were destroyed by dispase treatment. Immunoblotting revealed that dispase fragmented occludin, whereas it remained unchanged in the intact urothelial cell sheets. Novel urothelial cell sheets obtained by culture on temperature-responsive culture surfaces were successfully harvested much less destructively than with dispase. This technology should prove useful in urinary tract tissue engineering in the near future.