Single-Shot Ternary Readout of Two-Electron Spin States in a Quantum Dot Using Spin Filtering by Quantum Hall Edge States.

We report on the single-shot readout of three two-electron spin states-a singlet and two triplet substates-whose z components of spin angular momentum are 0 and +1, in a gate-defined GaAs single quantum dot. The three spin states are distinguished by detecting spin-dependent tunnel rates that arise from two mechanisms: spin filtering by spin-resolved edge states and spin-orbital correlation with orbital-dependent tunneling. The three states form one ground state and two excited states, and we observe the spin relaxation dynamics among the three spin states.

Two- and three-electron Pauli spin blockade in series-coupled triple quantum dots.

We investigate two- and three-electron spin blockade in three vertical quantum dots (QDs) coupled in series. Two-electron spin blockade is found in a region where sequential tunneling through all QDs is forbidden but tunneling involving virtual hopping through an empty QD is allowed. It is observed only for the hole cycle with a distinct bias threshold for access to the triplet state. Three-electron spin blockade involving the quadruplet state is observed for nonequibilium conditions where sequential tunneling is allowed and the triplet state is accessible. Our results shine light on the importance of the nonequibilium conditions to obtain sufficient population of triplet and quadruplet states necessary for spin blockade.

Nondestructive real-time measurement of charge and spin dynamics of photoelectrons in a double quantum dot.

We demonstrate one and two photoelectron trapping and the subsequent dynamics associated with interdot transfer in double quantum dots over a time scale much shorter than the typical spin lifetime. Identification of photoelectron trapping is achieved via resonant interdot tunneling of the photoelectrons in the excited states. The interdot transfer enables detection of single photoelectrons in a nondestructive manner. When two photoelectrons are trapped at almost the same time we observed that the interdot resonant tunneling is strongly affected by the Coulomb interaction between the electrons. Finally the influence of the two-electron singlet-triplet state hybridization has been detected using the interdot tunneling of a photoelectron.

Aharonov-Bohm oscillations changed by indirect interdot tunneling via electrodes in parallel-coupled vertical double quantum dots.

Aharonov-Bohm (AB) oscillations are studied for a parallel-coupled vertical double quantum dot with a common source and drain electrode. We observe AB oscillations of current via a one-electron bonding state as the ground state and an antibonding state as the excited state. As the center gate voltage becomes more negative, the oscillation period is clearly halved for both the bonding and antibonding states, and the phase changes by half a period for the antibonding state. This result can be explained by a calculation that takes account of the indirect interdot coupling via the two electrodes.

Persistent glomerular hematuria in living kidney donors confers a risk of progressive kidney disease in donors after heminephrectomy.

Although glomerular hematuria is likely a sign of chronic kidney disease that will develop into overt nephropathy after donation, it remains unclear whether prospective donors with hematuria should be excluded. We reviewed the medical records of 242 donors who donated at our institution from 2001 to 2007 and surveyed the prevalence of hematuria pre- and postdonation. We then investigated the association of hematuria with proteinuria postdonation and trends in glomerular filtration rate. Before donation, 8.3% of 242 donors presented with persistent hematuria, a finding that was significantly associated with dysmorphic hematuria before donation. Most cases of predonation persistent hematuria persisted after donation, and the overall prevalence increased to 15.3%. During a median follow-up period of 2.3 years after donation, 8.3% developed persistent proteinuria, with incidence being significantly higher in donors having persistent hematuria with dysmorphic red blood cells (d-RBC) both before and after donation. Postdonation persistent hematuria with d-RBC was also associated with a progressive decline in renal function. These results indicate that persistent glomerular hematuria is strongly associated with a higher incidence of postdonation progressive kidney disease. Potential donors with persistent glomerular hematuria should be excluded, while those with isolated hematuria need to be evaluated with heightened caution.

How do living kidney donors develop end-stage renal disease?

The clinical course and risk factors for developing end-stage renal disease (ESRD) after heminephrectomy in living kidney donors have scarcely been investigated. We reviewed medical records and identified eight case donors who developed chronic kidney disease (CKD) stage 5 or ESRD, and subsequently investigated the association between postoperative clinical courses and changes in renal function. To conduct a case-control study, we also selected a control group comprising 24 donors who had maintained stable renal function and were matched for age, sex and follow-up time since donation. Except for one donor who developed ESRD caused by a traffic accident, none of the donors developed progressive renal dysfunction immediately after donation. Their renal functions remained stable for a long period of time, but started to decline after developing new comorbidities, especially risk factors known as progression factors (proteinuria or hypertension) or accelerating factors (cardiovascular [CV] event or infection) of CKD. As compared with the control donors, incidence of postoperative persistent proteinuria, acute CV event, severe infection and hospitalization due to accelerating factors of CKD were significantly higher in the case donors. These results suggest the importance of long-term (more than 10 years) follow-up of donors with special attention on the risk factors of CKD.

Caveolin-1 expression is a distinct feature of chronic rejection-induced transplant capillaropathy.

Peritubular capillary basement membrane multilayering (PTCBMML) is a pathological landmark of chronic rejection-induced transplant capillaropathy (TC), but its cellular mechanisms are not fully understood. We observed de novo caveolae formation in endothelial cells in TC under electron microscopy. To examine the role of caveolae and their structural components in TC, biopsy samples from cases of chronic rejection were double-immunostained for Caveolin-1 (Cav-1) and Pathologische Anatomie Leiden-endothelium (PAL-E; a marker of peritubular capillary [PC]). Thirty-two cases of chronic rejection (group I) were compared with 18 cases of interstitial fibrosis and tubular atrophy with no evidence of any specific etiology (IF/TA; group II) and eight cases of peritubular capillaritis (group III). The Cav-1/PAL-E immunoreactivities in groups I-III (%Cav-1/PAL-E) were 41.8+/-23.1%, 8.1+/-7.3% (p < 0.01 vs. group I) and 12.7+/-7.4% (p < 0.01 vs. group I), respectively. Furthermore, multiple linear regression models demonstrated that %Cav-1/PAL-E was independently associated with the PTCBMML grade and reduced PC number. No correlation was observed between %Cav-1/PAL-E and PC C4d deposition in group I. We conclude that de novo caveolae formation in PC endothelia is involved in TC in chronic rejection.

Effects of immunosuppressants on the progression of hepatitis C in hepatitis C virus-positive renal transplantation and the usefulness of interferon therapy.

OBJECTIVE: The purpose of this study was to analyze the effects of immunosuppressants on hepatitis C virus (HCV) replication to establish optimal immunosuppressive therapy in HCV-positive renal transplantation. MATERIALS AND METHODS: Cyclosporine (CsA), tacrolimus (Tac), mycophenolate acid (MPA), the active metabolite of mycophenolate mofetil (MMF), and methylprednisolone (MP) were administered to HCV replicon cells alone or in combination with interferon (IFN). HCV RNA was quantitatively determined. Of our 2064 recipients of renal transplantations between 1980 and 2005, 153 were HCV-positive. We analyzed changes in hepatic function and the efficacy of IFN therapy in these patients. RESULTS: Only CsA strongly inhibited the growth of HCV RNA (13.1% at 1.0 microg/mL). MPA enhanced the inhibition of the growth of HCV RNA in the presence of IFN. Tac and MP reduced, rather than enhanced, the efficacy of IFN. Progression to chronic hepatitis occurred in a significantly smaller number of patients in the CsA than the Tac group (6 vs 19; P = .04). Serum alanine aminotransferase (ALT) levels were comparable pretransplantation and posttransplantation in the CsA group (24.8 +/- 20.5 vs 28.9 +/- 28.3 IU/L, respectively, while a significant elevation was noted in the Tac group (22.2 +/- 21.5 vs 32.6 +/- 30.8 IU/L, respectively; P = .024). Two of 4 patients who underwent combination therapy with IFN and ribavirin during treatment with CsA and MMF obtained an HCV-negative status for over 24 weeks. CONCLUSIONS: CsA effectively prevents the progression of chronic hepatitis in HCV-positive renal transplant patients. A greater response rate can be expected by concurrent administration of CsA and MMF under IFN therapy.

Successful third kidney transplantation with intensive immunosuppression in a highly sensitized recipient.

HLA sensitization associated with previous kidney transplantation is a major drawback to retransplantation. Recently we successfully performed a third graft using intensive immunosuppression for a highly sensitized recipient. The patient was a 31-year-old man who had previously undergone a living donor graft from his father at our institute in 1999. His kidney graft function had deteriorated due to chronic allograft nephropathy, returning to hemodialysis therapy in 2005. He received a second graft from a deceased donor in another country on August 14, 2006. It rejected on postoperative day 3 possibly due to acute accelerated rejection. He was offered a third kidney from his brother. Panel-reactive antibody (PRA) tested before the third procedure revealed positive class I (88%) and class II (96%) PRAs. Mycophenolate mofetil (MMF) was started 3 weeks before the third transplantation, and preoperative plasmapheresis performed thrice. He underwent the living donor graft on March 9, 2007. Immunosuppression consisted of tacrolimus, MMF, methylprednisolone, and basiliximab. Immediately afterward there was a sudden decrease in allograft blood flow and urine output, implying hyperacute rejection. Following treatment with plasmapheresis and a single dose of rituximab (200 mg), the kidney allograft function recovered, although the PRA at 3 weeks was still positive. Six months posttransplantation, he is well with a creatinine of 0.9 mg/dL. Our protocol may reduce the risk for graft loss in a highly sensitized transplant recipient.

Hand-assisted laparoscopic splenectomy in ABO-incompatible kidney transplant recipients.

OBJECTIVE: We perform living-related ABO-incompatible kidney transplantations to alleviate the organ shortage in our country. Splenectomy has been performed routinely in these recipients, although its clinical significance remains controversial. In this study, we have reported our experience with a hand-assisted laparoscopic splenectomy (HALS) technique. METHODS: Between April 2000 and December 2006, 50 patients (23 males) underwent ABO-incompatible kidney transplantation with HALS. The mean age and weight of the recipients were 44 +/- 13 years and 56 +/- 12 kg, respectively. All patients underwent preoperative plasmapheresis to reduce isoagglutinin (A and/or B antibody). In 6/50 patients, a hand-assisted device was placed through a peritoneal window in the right lower abdominal skin incision for kidney engraftment. In the remaining 44 patients, a 6-cm upper midline or periumbilical midline incision was made for the hand-assisted device in the lateral position. RESULTS: An ABO-incompatible procedure was completed successfully in all cases. The average HALS time was 118 +/- 42 minutes, with an average pneumoperitoneum time of 79 +/- 40 minutes and average blood loss of 48 +/- 81 g. There were two conversions to open splenectomy because of intraoperative bleeding and suspected pneumothorax. Two other cases required relaparotomy because of hematoma and perforation of the ileum. Successfully operations were achieved through the previous periumbilical incision. CONCLUSIONS: Although meticulous, rigorous surgical technique is essential, HALS is safe and feasible for recipients of ABO-incompatible grafts with tissue weakness and a bleeding tendency because of renal failure and preoperative plasmapheresis.

Present status of pancreas transplantation in Japan--donation predominantly from marginal donors and modified surgical technique: report of Japan pancreas transplantation registry.

In Japan, organ donation has been still limited because of the strict donor criteria. The aim of this study was to show the effectiveness of pancreas transplantation (PTx) by analyzing the outcomes even under poor donor conditions. Thirty-six cases of PTx (32 simultaneous pancreas and kidney transplantations [SPK], 4 pancreas after kidney transplantations) performed during the last 8 years were examined especially for donor characteristics. Mean donor age of 41.4 +/- 11.9 years was considerably older compared with that in the United States and Europe; donors aged over 40 years comprised 67% of the total. According to the criteria described by Kapur, 29 cases (81%) in our series would be considered marginal. Thus, to increase blood supply into the pancreatic head, the gastroduodenal artery (GDA) was anastomosed using donor artery to common hepatic artery or iliac Y graft. These procedures were performed in 16 of the 24 cases in which there was liver procurement. Eventually, 34 cases (94%) preserved GDA continuity. Mean total cold ischemic time of pancreatic grafts was 12 hours 15 minutes. Of 214 registrants, 17 patients on the waiting list for SPK died of diabetic complications. To date, patient survival remains 100% with a mean follow-up period of 33 months. Pancreas graft survivals at 1, 3, and 5 years posttransplantation were 92%, 80%, and 80%, respectively. In contrast, kidney survivals were 91%, 91%, and 91%, respectively. The integrity of the pancreas head and duodenum by preservation of the GDA continuity might have decreased the risk associated with the marginal donors.

Population-based estimates of breast cancer risks associated with ATM gene variants c.7271T>G and c.1066-6T>G (IVS10-6T>G) from the Breast Cancer Family Registry.

The ATM gene variants segregating in ataxia-telangiectasia families are associated with increased breast cancer risk, but the contribution of specific variants has been difficult to estimate. Previous small studies suggested two functional variants, c.7271T>G and c.1066-6T>G (IVS10-6T>G), are associated with increased risk. Using population-based blood samples we found that 7 out of 3,743 breast cancer cases (0.2%) and 0 out of 1,268 controls were heterozygous for the c.7271T>G allele (P=0.1). In cases, this allele was more prevalent in women with an affected mother (odds ratio [OR]=5.5, 95% confidence interval [CI]=1.2-25.5; P=0.04) and delayed child-bearing (OR=5.1; 95% CI=1.0-25.6; P=0.05). The estimated cumulative breast cancer risk to age 70 years (penetrance) was 52% (95% CI=28-80%; hazard ratio [HR]=8.6; 95% CI=3.9-18.9; P<0.0001). In contrast, 13 of 3,757 breast cancer cases (0.3%) and 10 of 1,268 controls (0.8%) were heterozygous for the c.1066-6T>G allele (OR=0.4; 95% CI=0.2-1.0; P=0.05), and the penetrance was not increased (P=0.5). These findings suggest that although the more common c.1066-6T>G variant is not associated with breast cancer, the rare ATM c.7271T>G variant is associated with a substantially elevated risk. Since c.7271T>G is only one of many rare ATM variants predicted to have deleterious consequences on protein function, an effective means of identifying and grouping these variants is essential to assess the contribution of ATM variants to individual risk and to the incidence of breast cancer in the population.

A pathological analysis of lymphatic vessels in early renal allograft.

Lymphatic vessels are an essential part of the immunological response. Nevertheless, little is known about the pathology of renal transplant rejection. In part the reason may be not distinguishing peritubular capillaries from lymphatic vessels by periodic acid-Schiff (PAS) staining. This study examined the morphology of lymphatic vessels in early renal allografts using double staining with PAS and podoplanin. The 41 cases were divided into four categories: (I) acute antibody-mediated rejection, (II) acute cellular rejection, (III) peritubular capillaritis only, and (IV) controls. I through III had the evidence of peritubular capillaritis exceeding grade 1 on a biopsy obtained an average of 17.3 +/- 5.5 days after kidney transplantation. In addition, each lymphatic vessel density (LVD) and nodular lesion of lymphocytes (NL) were quantified as the number of each podoplanin-positive vascular profiles and NL per unit area of cortex measured Lumina Vision (Mitani). The average of the LVD was 73.0, 35.1, 37.1, and 8.1 per 10 mm2 for groups I to IV and the average of NL was 2.8, 5.5, 1.3, 0.9, respectively. There was a significant correlation between LVD and NL. NL showed a strong relation to the accumulation of lymphocytes in lymphatic vessels (AL); 22% of the AL scores were greater than the peritubular capillaritis grade. We found lymphatic vessels to be strongly associated with any kind of inflammatory process that occurred unexpectedly soon after kidney transplantation. In addition, to avoid misdiagnosis of peritubular capillaritis, NL in early renal allograft must especially be excluded.

Modulation of prostaglandin metabolism by K-MAP and prevention of toxic effect of cyclosporin on pancreatic islet cells.

The injection of 25 mg/kg i.p. cyclosporin (CsA) for 3 wk caused marked functional and morphological deteriorations of pancreatic islet cells in Wistar rats that were prevented by the combined administration of p-aminobenzoic acid-N-D-mannoside sodium salt (K-MAP). In this article, the toxic effect of CsA on pancreatic islet cells and the preventive effect of K-MAP on CsA-associated islet cell toxicity were investigated. Prolonged hyperglycemia and depressed insulin secretion after the glucose challenge observed in CsA-treated rats could be prevented by the combined administration of 300 and 900 mg/kg K-MAP. Cytoplasmic vacuolizations and a decrease in the number of mitochondria, intact endoplasmic reticula, secretory granules, and insulin-positive cells, as revealed by peroxidase-antiperoxidase staining, could also be prevented by the administration of 900 mg/kg K-MAP. This preventive effect of K-MAP on CsA-associated islet cell toxicity may suggest the combined use of K-MAP with CsA in pancreas transplantation and treatment of insulin-dependent diabetes.

Loss of peritubular capillaries in the development of chronic allograft nephropathy.

BACKGROUND: Chronic allograft nephropathy (CAN) remains the most important cause of late renal graft loss. In this study, we examined the role of peritubular capillary (PTC) injury in the development of CAN. METHODS: We studied renal biopsies (n = 79) obtained from grafts with CAN. PTC injury was examined morphologically by immunohistochemistry for CD34. These findings were correlated with interstitial fibrosis and graft dysfunction. Humoral immunity involved in CAN was studied by C4d staining. RESULTS: The CAN cases in the present study included chronic rejection (CR) (n = 14, 17.8%) and C4d-positive chronic humoral rejection (CHR; n = 6, 42.9% in CR cases). Irrespective of CR, CHR, or other CAN, the development of CAN was characterized by injury to and loss of identifiable PTCs, accompanied with the development of interstitial fibrosis. In CR and CHR cases, the loss of PTCs was prominent and seemed to progress within a relatively short period after transplantation. A decrease in the number of PTCs significantly correlated with the development of interstitial fibrosis (r = -0.75, P < .001) and impairment of graft function (r = -0.69, P < .001). CONCLUSIONS: Irrespective of whether CR, CHR, or other factors contribute to CAN, the processes involved in its development appear similar and are characterized by progressive injury and loss of PTCs, with the development of renal scarring. Immunohistochemistry for CD34 in human renal biopsies is a useful method for the detection of microvascular injury.

The start of an islet transplantation program in Japan.

In Japan, pancreas donation had become possible from cadaveric donor sources, both heart-beating or non-heart-beating (NHB). Pancreas allografts have been distributed in the organ allocation system of the Japan Organ Transplant Network. Meanwhile, islet transplantation has been categorized as a tissue transplantation; it is free from legal restraints. Thus, pancreata for islet isolation must be obtained from NHB donors. Herein we report the starting program and preliminary results of islet transplantation in Japan. Selection and listing criteria for transplantation include regional priority, ABO blood type, previous islet transplant status with insulin independence, and a longer waiting time. Five institutes in Japan (Fukushima, Chiba, Kyoto, Kobe, and Fukuoka) are prepared to start programs. A two-layer cold storage method using perfluorocarbons and UW solution is recommended for pancreas preservation. Islet isolation and purification procedures are performed according to institute-specific protocol. Immunosuppression is based on sirolimus/tacrolimus combined with basiliximab induction. Two or three consecutive infusions of >5000 IE/kg are planned for each recipient until achieving insulin independence. Twenty-seven isolations and 14 transplants were performed in eight non-insulin-dependent diabetes mellitus (IDDM) recipients. Almost all (26 of 27) were NHB donors. All recipients are free from hypoglycemic episode after transplantation. One of these recipients is insulin independent; the others are currently on minimal doses of exogenous insulin. The feasibility of islet transplantation using NHB donors was confirmed using a two-layer cold storage method and a steroid-free immunosuppressive protocol, with a high rate of graft function.

Comparative study of clinical outcome in kidney transplantation between early steroid withdrawal protocol using basiliximab, calcineurin inhibitor, and mycophenolate mofetil and triple regimen consisting of calcineurin inhibitor, mycophenolate mofetil, and steroid.

AIMS: Effect of early steroid withdrawal protocol using basiliximab in kidney transplantation (KTx) on the clinical outcomes was investigated as compared with triple regimen. METHODS: Kidney transplant patients in group 1 (n = 62) were treated with 8 mg/kg of cyclosporine (CsA), 2000 mg of MMF, two bolus IV injections of 20 mg of basiliximab and 500 mg of methylprednisolone (MP) rapidly tapered and withdrawn at 14 postoperative days (POD). Group 2 (n = 56) was treated with same dose of CsA and MMF, and 250 mg of MP tapered and continued. Acute rejection (AR) episodes were treated with MP pulse therapy followed by muromonab CD3 (OKT3) in case of steroid-resistant rejection. RESULTS: In 46 of 62 cases (74.2%) in group 1, steroid was successfully withdrawn at 13.7 +/- 1.7 POD. Graft survival at 3, 6, and 12 months in group 1 was 100%, 100%, and 98.4% (one death with functioning graft), and 100%, 98.2%, and 96.4% in group 2, respectively. The incidence of AR was 12.9% for group 1 and 42.9% for group 2, among which 21 cases in group 2 were treated with ALG or OKT3; no patient needed ALG or OKT3 in group 1. Fifteen cases in group 1 and 13 cases in group 2 developed CMV antigenemia, among which febrile episode was exhibited in 3 cases (4.8%) in group 1 and 5 cases (8.9%) in group 2. CONCLUSIONS: Early steroid withdrawal protocol using basiliximab is promising for reducing the incidence of AR (especially steroid-resistant rejection), CMV diseases, and steroid-related complications.

Cyclosporine-sparing effect of basiliximab in renal transplant recipients with mycophenolate mofetil.

UNLABELLED: Basiliximab added to a maintenance regimen consisting of cyclosporine microemulsion and mycophenolate mofetil was studied for its effectiveness in allowing early steroid withdrawal in renal transplantation. Furthermore, the cyclosporine-sparing effects between groups with and without basiliximab induction therapy were compared. PATIENTS: Between September 2001 and June 2003, 90 patients underwent renal transplants with cyclosporine-based immunosuppression, namely, cyclosporine, mycophenolate mofetil, and methylprednisolone, (group 1; n = 25). During the latter half of the study basiliximab was administered during the induction phase (group 2; n = 65). In group 2, steroids were completely withdrawn on postoperative day 14 in 57 patients. RESULTS: The incidence of acute rejection was significantly higher among group 1 patients (P = .005). The incidence of steroid-resistant rejection in group 1 patients was significantly higher (P = .025). At each time point cyclosporine levels in group 1 patients were significantly higher (P < .01). The incidence of infection was comparable between the groups. Patient and graft survival rates in group 1 were 100% and 100%; in group 2, they were 99% and 99%, respectively. In group 2, steroids were discontinued in 57 patients with permanent withdrawal achieved in 32 patients (56%). CONCLUSION: The use of basiliximab, together with mycophenolate mofetil allowed for a significant reduction in the cyclosporine dose without increasing the risk of acute rejection. Although further follow-up is necessary to confirm the effect, this regimen may attenuate cyclosporine nephrotoxicity thereby affecting the long-term outcomes of renal transplantation.

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.

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.