The evolution of immunosuppression with FK506 in pediatric living-related liver transplantation

Portal vein complications in pediatric living donor liver transplantation using left-side grafts

The aim of this report is to assess the rate of portal vein complications (PVCs), the success rate of treatment for PVCs and the prognosis of patients with PVCs for pediatric living donor liver transplantation (LDLT). Pre- and postoperative records of 521 pediatric LDLTs, using left-side grafts were retrospectively reviewed. The overall rate of PVC was 9%, with early PVC occurring in nine patients (1.7%) with a mortality rate of 67% and late PVC in 38 patients (7.3%). Fifteen of these patients with late PVC showed complete portal vein occlusion despite various treatments, and in six of them the graft was lost. Histological examination revealed fibrosis in portal areas in 13 patients, around the central veins associated with cholestasis in the parenchyma in 10, and hepatocyte ballooning in 12. Correction of portal vein flow or retransplantation is necessary for the rescue of patients with early PVCs. Graft loss in the long term may be high with the occurrence of liver failure or portal hypertension related causes, such as hepatopulmonary syndrome and gastrointestinal bleeding in patients with late PVCs. For the rescue of these patients, especially for patients with body weight < 6 kg, regular monitoring of portal vein flow is essential.

Expansion of selection criteria for patients with hepatocellular carcinoma in living donor liver transplantation

In the present study, the results of living donor liver transplantation (LDLT) for 125 hepatocellular carcinoma (HCC) patients were analyzed to determine optimal criteria exceeding the Milan criteria (MC) but still with predictably good outcomes. On the basis of pretransplant imaging studies, 70 patients met the MC, and 55 patients did not. Patients who exceeded the MC but presented with <or=10 tumors all<or=5 cm in diameter (n=30) displayed 5-year recurrence rates (7.3%) similar to those of patients within the MC (9.7%, P=0.8787). According to the results of multivariate analysis of risk factors for recurrence among preoperative tumor variables, we have defined the new criteria, namely <or=10 tumors all<or=5 cm in diameter and protein induced by vitamin K absence or antagonist-II (PIVKA-II)<or=400 mAU/mL. The 78 patients who met the new criteria showed significantly lower 5-year recurrence rates (4.9%) than the 40 patients who exceeded them (60.5%, P<0.0001). Similarly, 5-year survival rates significantly differed between these groups (86.7% versus 34.4%, respectively; P<0.0001). In conclusion, selection criteria for patients with HCC undergoing LDLT may be safely extended to <or=10 tumors all<or=5 cm in diameter and PIVKA-II<or=400 mAU/mL with acceptable outcomes.

Histological recurrence of autoimmune liver diseases after living-donor liver transplantation

BACKGROUND

The effects of living donor liver transplantation (LDLT) on the recurrence of autoimmune liver diseases have not been well documented. Genetic similarities may be beneficial to avoid severe rejection but may facilitate the recurrence of autoimmune diseases. Because familial occurrence of autoimmune liver diseases has been documented, there is a possibility that candidates for living-related donors may have the same disease as that of the recipients.

METHOD

Between November 1994 and June 2004, 50 patients with primary biliary cirrhosis (PBC) (16-non-blood-relative donors and 34 blood-relative donors), and 28 patients with primary sclerosing cholangitis (PSC) underwent LDLT in Kyoto University Hospital.

RESULTS

Among 35 patients with PBC who survived more than 1 year, 10 patients (29%) showed recurrent PBC, and nine of 10 patients with recurrent PBC (90%) were associated with blood-relative donors (mean follow-up period, 30 months; range, 2-68). Two recipients had donors with some clinical or histological characteristics of PBC, and their grafts developedrecurrent PBC. Cirrhosis or graft failure was not observed in any patients with recurrent PBC. For PSC patients who survived more than 1 year after LDLT, 13 of 22 (59%) showed PSC-compatible histology and radiological findings (mean follow-up period, 31 months; range, 22-71), and five died or underwent retransplantation. Human leukocyte antigen-DR15 was positively associated with susceptibility to PSC with ulcerative colitis. One donor was revealed to have retroperitoneal fibrosis without evidence of sclerosing cholangitis.

CONCLUSIONS

Blood-relative donors may be associated with susceptibility to recurrent autoimmune diseases. Recurrence of PSC, but not PBC, adversely affected the outcome of LDLT. Caution should be taken as blood-relative donors can be at risk of autoimmune liver diseases.

Impact of age older than 60 years in living donor liver transplantation

BACKGROUND

Living donor liver transplantation (LDLT) was extended to adults in recent years and more recently to older patients. The impact of donor age, analysis of preoperative risk factors for older LDLT recipients, and comparison of the complication rate between older and younger recipients were analyzed.

METHODS

Subjects included patients who underwent LDLT at Kyoto University Hospital from October 1996 to December 2005. Twenty-three donors were 60 years of age or older, and 411 were younger than 60 years of age. Fifty-two recipients were 60 years of age or older and 410 were younger than 60 years of age.

RESULTS

Postoperative recovery of liver function for donors and recipient/graft survival were not influenced by donor age. Hospital stay was longer in the donors 60 years of age or older than those younger than 60 years of age (P=0.02). The 5-year survival rates were 78.7% in recipients 60 years of age or older and 69.3% in younger recipients (P=0.26). Among preoperative risk factors for recipient survival rate, fulminant hepatic failure and preoperative status in the intensive care unit were significant (P<0.05). There were no significant differences in the incidence of postoperative complications for recipients.

CONCLUSIONS

Selected right lobe donors from individuals who were 60 years of age or older showed a similar postoperative course compared with younger donors. Moreover, LDLT is feasible for patients 60 years of age or older who do not require care in the intensive care unit or do not have fulminant hepatic failure.

Antidonor antibody in patients receiving ABO-identical and HLA-mismatched living donor liver transplants: effect on survival

We retrospectively determined the correlation of results of lymphocyte crossmatch tests by direct complement-dependent cytotoxicity, to the outcomes of 585 consecutive ABO-identical and human leukocyte antigen (HLA)-mismatched living donor liver transplants (LDLTs) (male:female=276:309; median age, 18 years). Crossmatch test results were positive in 14 recipients (2.4%). Patient survival at eight years in the crossmatch-positive group was significantly lower than in the crossmatch-negative group (positive group, 56.3%; negative group, 77.6%; P=0.014). The survival at five years of the crossmatch-positive group was significantly lower than the negative group in both older recipients (>or=18 years of age: positive group, 41.7%; negative group, 76.4%; P=0.0065), and female recipients (positive group, 37.5%; negative group, 81.9%; P=3.3x10). We conclude that antidonor antibodies have adverse effects on the clinical outcome of LDLTs, and that being female and/or older aged (>or=18 years of age) are risk factors for LDLT.

Outcomes of adult-to-adult living donor liver transplantation: a single institution's experience with 335 consecutive cases

OBJECTIVE

To determine outcomes for both donors and recipients of adult-to-adult living donor liver transplantation (AALDLT) and independent factors impacting those outcomes.

SUMMARY BACKGROUND DATA

Deceased donors for organ transplantation remain extremely rare, making living donor liver transplantation (LDLT) practically the sole therapeutic modality for patients with end-stage liver disease in Japan.

METHODS

Retrospective analysis of initial LDLT for 335 consecutive adult (>or=18 years) patients performed between November 1994 and December 2003.

RESULTS

: Of the 335 recipients, 275 received right-liver grafts and the remaining 60 recipients received non-right-liver grafts. Three of the 335 liver grafts were domino-splitting livers. Sixty of the 332 donors other than the domino-donors showed major postoperative complications. Multivariate analysis indicated that accumulation of case experience significantly and advantageously affected the surgical outcomes of these living liver donors, and right-liver donation and prolonged donor operation time were shown to be independent risk factors of major complications in the donors. Post-transplant patient and graft survival estimates were 73.1% and 72.5% at 1 year, 67.7% and 66.3% at 4 years, and 64.7% and 61.9% at 7 years, respectively. Obvious pretransplant encephalopathy, a higher (>or=31) modified Model for End-stage Liver Disease score (including points for persistent ascites and low serum sodium) and higher donor age (>or=50 years) were indicated as independent factors predictive of graft failure (graft loss or death) in the multivariate analysis.

CONCLUSIONS

Graft type and degree of experience exerted a significant impact on the surgical outcomes of AALDLT donors but did not significantly affect the survival outcomes of AALDLT recipients. Better pretransplant conditions and younger age (<50 years) among the living donors appeared to be advantageous in terms of gaining better survival outcomes of patients undergoing AALDLT.

Impact of human leukocyte antigen mismatching on outcomes of living donor liver transplantation for primary biliary cirrhosis

Patient selection criteria of deceased donor liver transplantation for primary biliary cirrhosis (PBC) are almost completely established. The aim of this study was to establish selection criteria for both patients and donors of living donor liver transplantation (LDLT) for PBC. We used univariate and multivariate analyses to examine patient and donor characteristics of our first 50 cases of LDLT for PBC to elucidate factors that significantly impacted patient survival or disease recurrence after LDLT in the univariate and/or multivariate analyses. Multivariate analysis demonstrated that the presence of persistent ascites before LDLT, a higher number of human leukocyte antigen (HLA)-A, -B, and -DR mismatches between donor and recipient, and donor age >or=50 years were factors significantly associated with early posttransplant death. Independent risk factors for PBC recurrence after LDLT were a lower number of HLA mismatches between donor and recipient, and a lower average trough level of tacrolimus within 1 year after LDLT. Specifically, the lower the number of HLA-A, -B, and -DR mismatches or the average trough level of tacrolimus within 1 year after LDLT, the higher the possibility of developing a recurrence of PBC. In conclusion, the absence of persistent ascites before LDLT, a lower number of HLA-A, -B, and -DR mismatches between donor and recipient, and a younger donor (<50 years) are preferred for gaining acceptable survival outcomes for the transplant. However, a lower number of HLA-A, -B, and -DR mismatches between donor and recipient may be a risk factor for PBC recurrence.

Endoscopic treatment of biliary complications after right-lobe living-donor liver transplantation with duct-to-duct biliary anastomosis

BACKGROUND/PURPOSE

The aims of this study were to characterize the features of the biliary complications that occur after right-lobe living-donor liver transplantation (RL-LDLT) with duct-to-duct biliary anastomosis, and to evaluate the efficacy of treating biliary complications endoscopically.

METHODS

The records of 273 consecutive patients who underwent RL-LDLT with duct-to-duct biliary anastomosis from July 1999 through July 2005 at Kyoto University Hospital were reviewed to determine the overall incidence of postoperative biliary complications and the outcome of endoscopic repair of those complications.

RESULTS

Biliary complications occurred in 93 (34.1%) of the patients. These complications were: 80 biliary strictures (75 anastomotic and 5 nonanastomotic) and 16 biliary leakages (5 patients with biliary leakage also had a biliary stricture); most (72%) of the anastomotic strictures were complex (i.e., fork-shaped or trident-shaped). The strictures and leakages were repaired by the endoscopic placement of multiple inside stents above the sphincter of Oddi, and by nasobiliary drainage, respectively. The procedure was successful in repairing 51 (68.0%) of the anastomotic strictures and 8 (50.0%) of the biliary leakages.

CONCLUSIONS

Endoscopic stenting of the bile ducts is efficacious in treating biliary complications related to RL-LDLT with duct-to-duct biliary anastomosis and the stenting should be attempted before surgical revision of strictures and leakages.

Long-term outcome of adult-to-adult living donor liver transplantation for post-Kasai biliary atresia

Our objective was to analyze problems in the perioperative management and long-term outcome of living donor liver transplantation (LDLT) for biliary atresia (BA). Many reports have described the effectiveness of liver transplantation (LT) for BA, particularly in pediatric cases, but little information is available regarding LT in adults (> or =16 years old). Between June 1990 and December 2004, 464 patients with BA underwent LDLT at Kyoto University Hospital, of whom 47 (10.1%) were older than 16 years. In this study, we compared the outcomes between adult (> or =16 years old) and pediatric (<16 years old) patients. The incidence of post-transplant intestinal perforation, intra-abdominal bleeding necessitating repeat laparotomy and biliary leakage was significantly higher (p < 0.0001, <0.001 and <0.001, respectively) in adults. Overall cumulative 1-, 5- and 10-year survival rates in pediatric patients were significantly higher (p < 0.005) than in adults. Two independent prognostic determinants of survival were identified: a MELD score over 20 and post-transplant complications requiring repeat laparotomy. Outcome of LDLT in adult BA patients was poorer than in pediatric patients. It seems likely that LT will be the radical treatment of choice for BA and that LDLT should be considered proactively at the earliest possible stage.

Long-term outcomes of 600 living donor liver transplants for pediatric patients at a single center

This report concerns the long-term outcome of living donor liver transplantation (LDLT) for pediatric patients at a single center. Between June 1990 and December 2003, a total of 600 LDLTs, including 568 primary transplantations and 32 retransplantations, were performed for pediatric patients, who were immunosuppressed with FK506 and low-dose corticosteroids. Patient survival at 1, 5, and 10 years were 84.6%, 82.4%, and 77.2%, respectively, and the corresponding findings for graft survivals were 84.1%, 80.9%, and 74.5%. Multivariate analysis demonstrated that fulminant hepatic failure (FHF), a graft vs. body weight (GBWR) ratio of <0.8, and ABO-incompatible transplants were independently associated with both patient and graft survival. The retransplantation rate was 6%, and 55 patients (9.7%) have been completely weaned off immunosuppressants. Long-term patient and graft survival after pediatric LDLT for a large cohort of children at our hospital were found to be as good as those for cadaveric liver transplantation, although this series includes 13% liver transplantations with ABO-incompatible donors, which are obviously inferior in patient and graft survival. To obtain better outcomes for patients with FHF and for patients with ABO-incompatible transplants, immunosuppressive therapy needs to be improved.

Vascular reconstruction and complications in living donor liver transplantation in infants weighing less than 6 kilograms: the Kyoto experience

Smaller-size infants undergoing living-donor liver transplantation (LDLT) are at increased risks of vascular complications because of their smaller vascular structures in addition to vascular pedicles of insufficient length for reconstruction. Out of 585 child patients transplanted between June 1990 and March 2005, 64 (10%) weighing less than 6 kg underwent 65 LDLTs. Median age and weight were 6.9 months (range: 1-16 months) and 5 kg (range: 2.8-5.9 kg), respectively. Forty-five lateral segment, 12 monosegment, and 8 reduced monosegment grafts were adopted, and median graft-to-recipient weight ratio was 4.4% (range: 2.3-9.7). Outflow obstruction occurred in only 1 patient (1.5%). Portal vein complication occurred in 9 (14%) including 5 with portal vein thrombosis. Hepatic artery thrombosis (HAT) occurred in 5 (7.7%). Patient and graft survivals were 73% and 72% at 1 yr, and 69% and 68% at 5 yr after LDLT, respectively. Thirteen of 22 grafts (58%) lost during the follow-up period occurred within the first 3 months posttransplantation. Overall graft survival in patients with and without portal vein complication was 67% and 65%, respectively (P = 0.54). Overall graft survival in patients with and without HAT was 40% and 67%, respectively. HAT significantly affected graft survival (P = 0.04). In conclusion, our surgical technique for smaller-size recipients resulted in an acceptable rate of vascular complications. Overcoming early posttransplantation complications will further improve outcomes in infantile LDLT.

Identification of novel defective HCV clones in liver transplant recipients with recurrent HCV infection

Patients with recurrent hepatitis C after liver transplantation usually have a high viral load and are generally resistant to interferon (IFN)-alpha2b plus ribavirin (RBV) therapy. However, it remains unclear whether pretreatment viral titre determines the effectiveness of combination therapy, especially in patients with a high viral load. The aim of this study was to identify the viral factors associated with a sustained virological response (SVR) to antiviral therapy in patients with recurrent hepatitis C after living-donor liver transplantation. Twenty-three patients with recurrent hepatitis C received combination therapy of IFN-alpha2b plus RBV. SVR was achieved in 7 of the 23 patients (30.4%). Predictive factors for SVR included a 2 log10 decline in Hepatitis C virus (HCV) RNA at 2 weeks after the start of therapy and disappearance of HCV RNA at 4 or 24 weeks after the start of therapy. As the pretreatment high viral load showed no association with SVR, we asked whether other viral factor was associated with the response to the combination therapy in transplant recipients. We found the several novel defective HCV clones in 4 of 12 recipients' sera. All defective HCV clones had deletions in the envelope region. Interestingly, no patients with defective clones showed a prompt decrease in HCV RNA after the start of IFN-alpha2b plus RBV therapy. Thus, early decline in serum HCV RNA after treatment was closely associated with SVR. The circulating defective HCV clones are present and might be associated with the response to the combination therapy in patients with recurrent hepatitis after liver transplantation.

A nomogram for predicting the optimal oral dosage of tacrolimus in liver transplant recipients with small-for-size grafts

No optimal tacrolimus dosage regimen suitable for clinical use in liver transplant recipients has yet been established. The purpose of this study was to determine the factors affecting the optimal dosage and pharmacokinetics of tacrolimus in living donor liver transplantation, and a nomogram for optimal tacrolimus dosage in the immediate postoperative period for recipients with small-for-size grafts was constructed. Twenty-four liver transplant patients (nine males and 15 females) and 24 donors (10 males and 14 females) were enrolled in this study. Two studies were performed. In study 1, the effect of the actual ratio of graft volume to standard liver volume (GV/SV ratio) on the elimination half-life (T1/2) of tacrolimus in the immediate postoperative period was analysed, and a nomogram for estimating the optimal oral dose of tacrolimus required to reach a target concentration was established. In study 2, the effect of donor age on the recovery of hepatic function with ability of the graft to eliminate tacrolimus was analysed. In the immediate postoperative period, T1/2 of tacrolimus showed great variability between patients, with values ranging from 16.3 to 110.9 h. Graft size (GV/SV ratio) is important and could influence intraindividual variations in the optimal dosage and T1/2 of tacrolimus. The recovered T1/2 ratio (T1/2 ratio=T1/2 1-10 d/T1/2 30-40 d), this ratio being related to the recovery of hepatic function with ability of the graft to eliminate tacrolimus, showed great variability between patients, with values ranging from 1.08 to 4.21 (mean+/-SD, 1.95+/-0.81). Age of the donor is a major factor affecting the recovered ratio of the graft to metabolize tacrolimus. The nomogram that we have constructed, based on graft size (GV/SV ratio), will easily provide optimal dose for each patient with small-for-size graft in the early postoperative period.

Living donor liver transplantation as a second-line therapeutic strategy for patients with hepatocellular carcinoma

Living donor liver transplantation (LDLT) has evolved to represent an important surgical strategy for patients with hepatocellular carcinoma (HCC). However, due to disadvantages, including donor risks and higher rates of perioperative complications, LDLT has been considered as a second-line treatment in Japan. The present study retrospectively evaluated clinical outcomes for 93 patients with HCC who underwent LDLT at our institute, including 44 patients who exceeded Milan criteria (MC). A total of 73 patients (78%) displayed a history of previous treatment for HCC using various nontransplant methods. Median follow-up was 24 months (range, 1-76 months). At 4 years after LDLT, overall patient survival rate was 64%, with similar rates for within-MC and over-MC groups (68% vs. 59%, respectively; P = 0.6548). However, cumulative recurrence rate was significantly higher in the over-MC group than in the within-MC group (35% vs. 15%, P = 0.0190). Regarding history of conventional treatment for HCC before LDLT, patients who had received only 1-2 previous treatments showed significantly lower recurrence rates than patients with > or =3 treatments (9% vs. 37%, P = 0.0411). In conclusion, LDLT may constitute an optional treatment with a chance of cure for patients with otherwise uncontrolled disease. However, repeated nontransplant treatments for recurrent HCC prior to LDLT may increase the risk of recurrence and impair the survival advantages conferred by LDLT.

Biliary reconstruction in right lobe living-donor liver transplantation: Comparison of different techniques in 321 recipients

OBJECTIVE

To assess the incidence of biliary complications after right lobe living-donor liver transplantation (LDLT) in patients undergoing duct-to-duct choledochocholedochostomy or Roux-en-Y choledochojejunostomy reconstruction.

SUMMARY BACKGROUND DATA

Biliary tract complications remain one of the most serious morbidities following liver transplantation. No large series has yet been carried out to compare the 2 techniques in LDLT. This study undertook a retrospective assessment of the relation between the method of biliary reconstruction used and the complications reported.

METHODS

Between February 1998 and June 2004, 321 patients received right lobe LDLT. Biliary reconstruction was achieved with Roux-en-Y choledochojejunostomy in 121 patients, duct-to-duct choledochocholedochostomy in 192 patients, and combined Roux-en-Y and duct-to-duct choledochocholedochostomy in 8 patients. The number of graft bile duct and anastomosis, mode of anastomosis, use of stent tube, and management of biliary complications were analyzed.

RESULTS

The overall incidence of biliary complications was 24.0%. Univariate analysis revealed that hepatic artery complications, cytomegalovirus infections, and blood type incompatibility were significant risk factors for biliary complications. The respective incidence of biliary leakage and stricture were 12.4% and 8.3% for Roux-en-Y, and 4.7% and 26.6% for duct-to-duct reconstruction. Duct-to-duct choledochocholedochostomy showed a significantly lower incidence of leakage and a higher incidence of stricture; however, 74.5% of the stricture was managed with endoscopic treatment.

CONCLUSIONS

The authors found an increase in the biliary stricture rate in the duct-to-duct choledochocholedochostomy group. Because of greater physiologic bilioenteric continuity, less incidence of leakage, and easy endoscopic access, duct-to-duct reconstruction represents a feasible technique in right lobe LDLT.

Biliary reconstruction in right lobe living-donor liver transplantation: Comparison of different techniques in 321 recipients

OBJECTIVE

To assess the incidence of biliary complications after right lobe living-donor liver transplantation (LDLT) in patients undergoing duct-to-duct choledochocholedochostomy or Roux-en-Y choledochojejunostomy reconstruction.

SUMMARY BACKGROUND DATA

Biliary tract complications remain one of the most serious morbidities following liver transplantation. No large series has yet been carried out to compare the 2 techniques in LDLT. This study undertook a retrospective assessment of the relation between the method of biliary reconstruction used and the complications reported.

METHODS

Between February 1998 and June 2004, 321 patients received right lobe LDLT. Biliary reconstruction was achieved with Roux-en-Y choledochojejunostomy in 121 patients, duct-to-duct choledochocholedochostomy in 192 patients, and combined Roux-en-Y and duct-to-duct choledochocholedochostomy in 8 patients. The number of graft bile duct and anastomosis, mode of anastomosis, use of stent tube, and management of biliary complications were analyzed.

RESULTS

The overall incidence of biliary complications was 24.0%. Univariate analysis revealed that hepatic artery complications, cytomegalovirus infections, and blood type incompatibility were significant risk factors for biliary complications. The respective incidence of biliary leakage and stricture were 12.4% and 8.3% for Roux-en-Y, and 4.7% and 26.6% for duct-to-duct reconstruction. Duct-to-duct choledochocholedochostomy showed a significantly lower incidence of leakage and a higher incidence of stricture; however, 74.5% of the stricture was managed with endoscopic treatment.

CONCLUSIONS

The authors found an increase in the biliary stricture rate in the duct-to-duct choledochocholedochostomy group. Because of greater physiologic bilioenteric continuity, less incidence of leakage, and easy endoscopic access, duct-to-duct reconstruction represents a feasible technique in right lobe LDLT.

Development of pulmonary hypertension in 5 patients after pediatric living-donor liver transplantation: de novo or secondary?

The development of portopulmonary hypertension (PH) in a patient with end-stage liver disease is related to high cardiac output and hyperdynamic circulation. However, PH following liver transplantation is not fully understood. Of 617 pediatric patients receiving transplants between June 1990 and March 2004, 5 (median age 12 yr, median weight 24.5 kg) were revealed to have portopulmonary hypertension (PH) after living-donor liver transplantation (LDLT), as confirmed by echocardiography and/or right heart catheterization. All children underwent LDLT for post-Kasai biliary atresia. In 2 patients with refractory biliary complications, PH developed following portal thrombosis; 2 with stable graft function, who had had intrapulmonary shunting (IPS) before LDLT, were found to have PH in spite of overcoming liver dysfunction due to hepatitis. PH developed shortly after distal splenorenal shunting in 1 patient, who suffered liver cirrhosis due to an intractable outflow blockage. The onset of PH ranged from 2.8 to 11 yr after LDLT, and mean pulmonary artery pressure (mPAP) estimated by echocardiography at the time of presentation ranged from 43 to 120 mmHg. Three of the 5 patients are alive under prostaglandin I2 (PGI2) treatment. Of these, 1 is prepared for retransplantation for an intractable complications of liver allograft, while the other 2 with satisfactory grafts are being considered for lung transplantation. Even after LDLT, PH can develop with portal hypertension. Periodic echocardiography is essential for early detection and treatment of PH especially in the recipients with portal hypertension not only preoperatively but also postoperatively.

Clinical Outcomes of Living Donor Liver Transplantation for Hepatitis C Virus (HCV)-Positive Patients

BACKGROUND

Whether hepatitis C virus recurrence occurs earlier and with greater severity for living donor liver transplantation (LDLT) than for deceased donor liver transplantation (DDLT) has recently become a subject of debate.

METHODS

We retrospectively evaluated clinical outcomes for a cohort of 91 HCV-positive patients who underwent LDLT at Kyoto University with a median follow-up period of 25 months.

RESULTS

Overall 5-year patient survival for HCV patients was similar to that for non-HCV patients (n=209) who underwent right-lobe LDLT at our institute (69% vs. 71%). Survival rate of patients without HCC (n=34) tended to be better than that of patients with HCC (n=57) (82% vs. 60%, P=0.069). According to annual liver biopsy, rate of fibrosis progression to stage 2 or more (representing significant fibrosis) was 39% at 2 years after LDLT. Univariate analysis showed that female recipient and male donor represented significant risk factors for significant fibrosis. Progression to severe recurrence (defined as the presence of liver cirrhosis (F4) in a liver biopsy and/or the development of clinical decompensation) was observed in five patients.

CONCLUSIONS

Postoperative patient survival was similar for HCV-positive and -negative recipients in our adult LDLT series. Rates of progression to severe disease due to HCV recurrence seemed comparable between our LDLT recipients and DDLT recipients described in the literature. Although longer-term follow-up is required, our results suggest that LDLT can produce acceptable outcomes also for patients suffering from HCV-related cirrhosis.

Impact of right lobe with middle hepatic vein graft in living-donor liver transplantation

Technical improvements in adult-to-adult living-donor liver transplantation (LDLT) have led to the use of right-lobe grafts to overcome the problems encountered with 'small-for-size grafts'. The major controversy remains that the venous drainage from anterior segment substantially depends on tributaries of the middle hepatic vein (MHV), and deprivation of such tributaries may critically influence the postoperative graft function. Right-lobe grafts with MHV could resolve the potential problem of congestion in anterior segment. From December 2000 to January 2004, we performed 217 right-lobe LDLTs for adult patients. Of these, 40 patients received a right lobe with MHV graft (18.4%). The overall cumulative 3-year graft survival rate of a right lobe with (n = 40) and without MHV (n = 177) was 86.2% and 74.8% (p = NS). The proximal side of the MHV and the drainage vein of segment IV to the MHV (the left medial superior vein) were preserved in 24 patients. All of them needed venous interposition graft for anastomosis. All patients had a patent right hepatic vein (RHV) and MHV anastomosis during the follow-up period. We adopted the right lobe with MHV graft in 40 LDLT cases. Vein graft is essential for safe MHV anastomosis in cases which preserve proximal side of the MHV.

Auxiliary partial orthotopic living donor liver transplantation: Kyoto University experience

Auxiliary partial orthotopic liver transplantation (APOLT) was initially indicated as a potentially reversible fulminant hepatic failure and non-cirrhotic metabolic liver disease to compensate for enzyme deficiency without complete removal of the native liver. We expand our indication of APOLT for small-for-size grafts to support the function of implanted grafts during the early post-operative period, and for ABO-incompatibility to sustain a patient's life if the patient has a graft failure. We retrospectively reviewed 31 patients undergoing APOLT from living donor. The indication of APOLT was fulminant hepatic failure in 6, non-cirrhotic metabolic liver disease in 6, small-for-size grafts in 13 and ABO-incompatible cases in 6. The cumulative survival rate for APOLT at 1 and 5 years was 57.9% and 50.6%, and 78.8% and 73.8% for standard LDLT. None of the patients who underwent transplantation with APOLT for fulminant hepatic failure had long-term patient survival. The incidence of acute cellular rejection was higher in APOLT (58.1%) than standard LDLT (35.0%). Biliary complication was higher and the need for retransplantation was greater in APOLT than standard LDLT (p < 0.01). The results suggest that the indications of APOLT should be reconsidered in view of the risk for complications and retransplantation.

Clinical pharmacokinetics and pharmacodynamics of tacrolimus in solid organ transplantation

The aim of this review is to analyse critically the recent literature on the clinical pharmacokinetics and pharmacodynamics of tacrolimus in solid organ transplant recipients. Dosage and target concentration recommendations for tacrolimus vary from centre to centre, and large pharmacokinetic variability makes it difficult to predict what concentration will be achieved with a particular dose or dosage change. Therapeutic ranges have not been based on statistical approaches. The majority of pharmacokinetic studies have involved intense blood sampling in small homogeneous groups in the immediate post-transplant period. Most have used nonspecific immunoassays and provide little information on pharmacokinetic variability. Demographic investigations seeking correlations between pharmacokinetic parameters and patient factors have generally looked at one covariate at a time and have involved small patient numbers. Factors reported to influence the pharmacokinetics of tacrolimus include the patient group studied, hepatic dysfunction, hepatitis C status, time after transplantation, patient age, donor liver characteristics, recipient race, haematocrit and albumin concentrations, diurnal rhythm, food administration, corticosteroid dosage, diarrhoea and cytochrome P450 (CYP) isoenzyme and P-glycoprotein expression. Population analyses are adding to our understanding of the pharmacokinetics of tacrolimus, but such investigations are still in their infancy. A significant proportion of model variability remains unexplained. Population modelling and Bayesian forecasting may be improved if CYP isoenzymes and/or P-glycoprotein expression could be considered as covariates. Reports have been conflicting as to whether low tacrolimus trough concentrations are related to rejection. Several studies have demonstrated a correlation between high trough concentrations and toxicity, particularly nephrotoxicity. The best predictor of pharmacological effect may be drug concentrations in the transplanted organ itself. Researchers have started to question current reliance on trough measurement during therapeutic drug monitoring, with instances of toxicity and rejection occurring when trough concentrations are within 'acceptable' ranges. The correlation between blood concentration and drug exposure can be improved by use of non-trough timepoints. However, controversy exists as to whether this will provide any great benefit, given the added complexity in monitoring. Investigators are now attempting to quantify the pharmacological effects of tacrolimus on immune cells through assays that measure in vivo calcineurin inhibition and markers of immunosuppression such as cytokine concentration. To date, no studies have correlated pharmacodynamic marker assay results with immunosuppressive efficacy, as determined by allograft outcome, or investigated the relationship between calcineurin inhibition and drug adverse effects. Little is known about the magnitude of the pharmacodynamic variability of tacrolimus.

Remaining caudate lobe in the right lobe graft in living donor liver transplantation: a blind spot?

The right margin of the caudate lobe is obscure. Therefore, a part of the caudate lobe (a part of the right side of the paracaval portion) seems almost always to remain with the right lobe graft during the standard harvesting procedure. We reviewed the intraoperative findings and the postoperative courses of donors and recipients of 11 consecutive living donor liver transplantations using right lobe grafts. Further, we used computed tomography during the postoperative course to investigate whether the remaining caudate lobe was present in the right lobe graft and whether it produced serious complications. Four recipients displayed an intraoperative bile leak from a remaining part of the caudate lobe after the completion of biliary reconstruction. With the exception of one case who developed repeated bile leakage from the same origin which eventually healed during a long-term postoperative course, Most recipients showed no postoperative biliary complications. Although a remaining caudate lobe was detected on postoperative computed tomography in all recipients, it produced no serious complications. In conclusion, a part of the right side of the paracaval portion of the caudate lobe almost always remains with a right lobe graft during the standard harvesting procedure. However, the implications of this phenomenon seem to be benign.

The variability of liver graft function and urinary 6beta-hydroxycortisol to cortisol ratio during liver regeneration in liver transplant recipients

The urinary ratio of 6beta-hydroxycortisol to cortisol (6beta-OHF/F) is considered to be the simplest and most practical method for estimation of hepatic cytochrome P450 3A4 (CYP3A4) activity as a non-invasive marker of human in vivo CYP3A4 activity. However, the inter- and intra-individual variability of the urinary 6beta-OHF/F ratio during liver regeneration and the effect of variability on optimal dose of tacrolimus have not yet been clarified. The objective of this study was to clarify the change in the urinary 6beta-OHF/F ratio during liver regeneration and to determine the effect of the liver graft function on the optimal tacrolimus dose in liver transplant recipients. Two liver transplant recipients (one male and one female) and eight healthy volunteers (five males and three females) were enrolled in this study. Urine samples were collected from the recipients from 08.00 hours for 24 h on post-transplant period, 1-10 and 21-30 days postoperatively. In the healthy volunteers, morning spot urine samples were collected at 08.00 hours. The mean urinary 6beta-OHF/F ratio in the immediate postoperative period was significantly low (p < 0.05). However, a marked difference in the regulation of CYP3A4 activity during liver regeneration was found in the two recipients. A significant correlation was found between the urinary 6beta-OHF/F ratio and the C/D ratio of tacrolimus (R = 0.658, p < 0.05). The urinary 6beta-OHF/F ratio is a useful probe for estimating the variability of CYP3A4 activity in liver transplant recipients in early postoperative phase. Future studies should evaluate the clinical usefulness of the urinary 6beta-OHF/F ratio as a predictor of tacrolimus pharmacokinetics in liver transplantation.

A pharmacodynamic investigation of tacrolimus in pediatric liver transplantation

Although monitoring of tacrolimus blood concentrations is standard clinical practice following liver transplantation, a greater understanding of the relationship between trough concentrations and clinical outcome is required. The aim of this study was to perform a pharmacodynamic investigation of tacrolimus in pediatric liver transplant recipients. A retrospective analysis was performed on 35 pediatric liver recipients who received oral tacrolimus as the primary immunosuppressant. Outcome data were recorded corresponding to the times that tacrolimus trough concentrations had been determined (using a validated high-performance liquid chromatography-tandem mass spectrometry assay). A Mann-Whitney rank sum test was used to investigate differences between median concentrations at which drug toxicity, infection, and organ rejection did and did not occur. Outcome data and trough concentrations were recorded from the immediate post-transplant time to over 3 years (656 concentration-effect measures). Seventy one percent of data was obtained after the first 90 days post-transplant. Patients were identified as having experienced hypomagnesemia (20), hypertension (14), hyperkalemia (12), infection (11), nephrotoxicity (8), diarrhea (6), hyperglycemia (3), neurotoxicity(3), and rejection (3) during retrospective follow-up. Median trough concentrations were significantly higher (P <.05) at times patients experienced tacrolimus toxicity compared to no toxicity for nephrotoxicity (11.8 vs. 6.1 ng/mL) and neurotoxicity (15.1 vs. 6.2 ng/mL) and at times when patients suffered from diarrhea (8.9 vs. 6.0 ng/mL). No significant difference could be found between median trough concentrations at which hypertension, hyperkalemia, hyperglycemia, infection and organ rejection did and did not occur. A statistically significant relationship exists between some tacrolimus toxicities and tacrolimus trough concentrations. To minimize toxicity in the later post-transplant period, we propose a target trough tacrolimus concentration of 6 ng/mL.

Impact of recipient age on outcome of ABO-incompatible living-donor liver transplantation

BACKGROUND

Transplantation of hepatic grafts from ABO-incompatible donors is controversial because of the risk of hyperacute rejection mediated by preformed anti-ABO antibodies. The aim of the present study was to evaluate the outcome of liver transplants performed with ABO-incompatible living-donor livers and to detect risk factors for development of complications.

METHODS

From June 1990 to February 2000, 66 patients, 10 months to 55 years old (median, 2 years old), received 68 ABO-incompatible living-donor liver grafts. The antibody titer and clinical course were followed prospectively during a period ranging from 3 to 11 years.

RESULTS

The 5-year patient survival was 59%, 76%, and 80% for ABO-incompatible, ABO-compatible, and ABO-identical grafts, respectively (P<0.01). In patients <1 year old, > or =1 to <8, > or =8 to <16, and and > or =16 years old, 5-year survival was 76%, 68%, 53%, and 22%, respectively. The incidence of intrahepatic biliary complications and hepatic necrosis in ABO-incompatible living-related grafts (18% and 8%, respectively) was significantly (P<0.0001) greater than in ABO-compatible and ABO-identical grafts (both 0.6% and 0%, respectively). Predictive risk factors for increased mortality and morbidity were age greater than 1 year and elevated anti-ABO titers before transplantation.

CONCLUSIONS

ABO-incompatible liver transplantation was carried out with relative safety in infants <1 year old but was not satisfactory in children >1 year in long-term follow-up. Patients aged >8 years remain at considerable risk of early fatal outcome because of hepatic necrosis, and new strategies to prevent antibody-mediated rejection are required.

Living-related liver transplantation for Alagille syndrome

Alagille syndrome (AGS) is an autosomal dominant genetic disorder characterized by chronic cholestasis, congenital heart disease, peculiar facies, butterfly-like vertebrae, and posterior embryotoxon. Liver dysfunction is the common presentation of AGS, and liver transplantation may be indicated. This study examines the outcome of living-related liver transplantation (LRLT) for AGS. Twenty patients with AGS (median age 5.0 years, range 0.6-12.9) underwent LRLT at Kyoto University Hospital between June 1990 and February 2002. Five potential donors were excluded because of paucity of intrahepatic bile ducts diagnosed by preoperative liver biopsy and one because of a hepatic vascular anomaly. The overall 5-year patient survival was 80.4%. Three patients died as the result of the following: complications related to surgery, heart failure caused by progressive pulmonary artery stenosis, and a graft with unsuspected bile duct paucity. Liver dysfunction was improved in all successful cases, and catch-up growth occurred in 90% of patients. LRLT is an efficacious treatment modality for AGS if donors are selected by cautious evaluation to rule out unsuspected bile duct paucity.

Changes in portal venous pressure in the early phase after living donor liver transplantation: pathogenesis and clinical implications

BACKGROUND

Although living-donor liver transplantation (LDLT) has been accepted for adult populations, the occurrence and pathogenesis of small-for-size syndrome remain highly controversial.

METHODS

Portal venous pressure (PVP) was measured in 79 cases of LDLT from anhepatic phase to day 14. PVP was monitored through a catheter inserted via the inferior mesenteric vein. In a separate series of seven cases of adult LDLT, the splenic artery was ligated following arterial reperfusion.

RESULTS

For days 2 to 4 and 9 to 11, recipients of small-for-size graft (<0.8% of body weight) displayed significantly higher PVP than recipients of larger grafts. The 13 patients with elevated mean PVP (>or=20 mm Hg) early in the first week (days 0-4) demonstrated significantly worse survival (84.5% vs. 38.5% at 6 months; P < 0.01), but this was not applicable to elevated mean PVP late in the first week (days 5-7). Elevated PVP early in the first week was also associated with higher incidence of bacteremia, cholestasis, prolonged prothrombin time, and ascites. Splenic artery ligation (SAL) immediately reduced PVP from 10 to 20 mm Hg (median, 16 mm Hg) to 9 to 13 mm Hg (median, 11 mm Hg; P = 0.02). Posttransplant PVP was significantly lower in SAL patients than in non-SAL patients from days 2 to 7 despite small graft size. Early PVP in SAL patients was consistently below 20 mm Hg, and survival was significantly better than in non-SAL patients with high early PVP (P < 0.01).

CONCLUSION

Elevated PVP in the early phase is strongly associated with poor patient survival attributable, at least in part, to small-for-size graft. Further elucidation of the pathogenesis behind this phenomenon and efforts to modify PVP will be key to improving results.

Long-term effects of liver transplantation on bone mineral density in children with end-stage liver disease: a 2-year prospective study

In children with end-stage liver disease, little is known regarding the long-term effects of liver transplantation on bone. In this 2-year prospective study, we evaluated the effects of liver transplantation on bone mineral density (BMD) and on other parameters of bone metabolism in 30 consecutive children with biliary atresia who underwent liver transplantation after failed Kasai operation. Tacrolimus and steroids were used as immunosuppressants. BMD of the first through fourth lumbar spine (L1-4) was measured by dual-energy radiographic absorptiometry (QDR-2000, Hologic) and expressed in Z-values. Before transplantation, Z-values of BMD, height, and weight were low in all patients (-3.4 +/- 0.34, -2.0 +/- 0.28, and -1.67 +/- O.16 [mean +/- SEM], respectively). Low BMD states were associated with low levels of serum 25-hydroxyvitamin D and serum levels of insulin-like growth factor-I (IGF-I), one of the most potent anabolic skeletal growth factors. Liver transplantation resulted in marked improvement in BMD values as well as in height and body weight: 24 months after transplantation, recovery was achieved in each parameter (0.16 +/- 0.30, -0.29 +/- 0.23, and 0.42 +/- 0.18, respectively). BMD recovery first was observed 3 months after transplantation. Moreover, these favorable effects of transplantation were accompanied by increases in serum levels of 25-hydroxyvitamin D and IGF-I. We conclude that liver transplantation effectively reverses the low bone mass status and growth retardation of children with end-stage liver disease.

Forecasting of Blood Tacrolimus Concentrations Based on the Bayesian Method in Adult Patients Receiving Living-Donor Liver Transplantation

OBJECTIVE

To evaluate Bayesian prediction of blood tacrolimus concentrations in adult patients receiving living-donor liver transplantation (LDLT) using previously obtained population pharmacokinetic parameters.

PATIENTS AND METHODS

Data were retrospectively collected from 47 adult patients receiving LDLT who were not included in the estimation of population pharmacokinetic parameters. Blood tacrolimus concentrations were predicted without or with the empirical Bayesian method using sparse samples obtained in the previous week. Predictive performance of the concentrations was evaluated by the mean prediction error (ME), mean absolute prediction error (MAE) and root mean square error (RMSE) as well as the percentage of successful predictions (percentage of absolute prediction error less than 3 microg/L, %PRED3).

RESULTS

Concentrations predicted by the population mean pharmacokinetic parameter values coincided well with observed concentrations during the period of tacrolimus infusion immediately after the operation. For concentrations during subsequent oral therapy with tacrolimus, predictability by the population mean pharmacokinetic parameter values alone was not satisfactory. Bayesian forecasting using one or two blood concentrations obtained in the previous week significantly decreased (p<0.05) MAE and RMSE compared with predictions based on the population mean pharmacokinetic parameters on postoperative days 21 and 28, but not on day 14. During postoperative days 15-21, %PRED3 was increased to 68.6% or 71.2% with the Bayesian method using one or two blood concentrations, respectively, from 44.9% with the population mean pharmacokinetic parameter values.

CONCLUSION

The present study demonstrated the applicability of the Bayesian method with use of one or two samples for prediction of blood tacrolimus concentrations in adult patients receiving LDLT.

Role of HLA compatibility in pediatric living-related liver transplantation

BACKGROUND

Human leukocyte antigen (HLA) matching is, at present, not used for the allocation of cadaveric hepatic allografts because the liver is generally believed to be less susceptible to HLA-mediated rejection. However, the exact role of HLA compatibility in the long-term outcome of liver transplantation is not yet clearly defined. One of the advantages of living-related liver transplantation (LRLT) could be a better histocompatibility between donor and recipient. This study aimed at an assessment of the influence of HLA compatibility in a large series of LRLTs.

METHODS

A total of 321 pediatric patients who underwent ABO-identical or ABO-compatible primary LRLT from the parental donors in the period between June 1990 and August 2000 were involved in the study. Graft survival, rejection episodes, and immunosuppression were evaluated from the viewpoint of HLA compatibility.

RESULTS

The overall 1- and 5-year graft survivals were 85.7% and 84.1%, respectively. The cumulative 5-year graft survivals in HLA 0-, 1-, 2- and 3-mismatch groups (A, B, and DR) were 100% (n=10), 78.9% (n=19), 86.2% (n=87), and 82.9% (n=205), respectively (P=0.525). The overall incidence of rejection during the follow-up period (median 66 months, range 16-139 months) was 46.1%. No significant difference was found in the incidence of rejection and rejection-free survival among the four groups. However, steroid-resistant rejection that necessitated OKT3 treatment (n=6) and chronic rejection (n=2) were recognized only in the 3-mismatch group. The whole-blood trough level of tacrolimus and the duration of steroid administration were not significantly different among the groups. The rate of the patients who succeeded in withdrawal from immunosuppression was also similar among the groups. However, the trough level of tacrolimus needed for maintenance of an acceptable liver function test during the chronic phase tended to be lower in well-matched pairs, and a high percentage of immunosuppressant-free patients were found in the 0-mismatch group. Fatal graft-versus-host disease developed in one patient with a complete one-way HLA-matched transplant.

CONCLUSION

We could not find any supportive evidence of beneficial effects of HLA-matching in pediatric LRLT. The potential benefit of HLA-matching for the reduction protocol for immunosuppressants may play a role in the withdrawal program. It appears unnecessary to pay attention to HLA compatibility in donor selection in LRLT, except for one-way HLA matching, or to adjust immunosuppression according to HLA compatibility.

Significance of serial real-time PCR monitoring of EBV genome load in living donor liver transplantation

BACKGROUND

Quantitative analysis of the Epstein-Barr virus (EBV) genome has been recently reported to be helpful for early identification of EBV viremia which could reduce the risk of post-transplantation lymphoproliferative disorder (PTLD).

AIM

To demonstrate the significance of serial monitoring of EBV genome load by real-time quantitative polymerase chain reaction (PCR) after living donor liver transplantation.

METHODS

From March 1999 to April 2000, the EBV genome load in peripheral blood mononuclear cells (PBMNC) was measured serially in a total of 15 recipients of living donor liver transplantation (LDLT) who had a symptomatic EBV infection.

RESULTS

In 15 patients, the mean values of the highest EBV DNA levels from the patients who had fever, URS, diarrhea, ascites, lymphadenopathy and PTLD were 36 232, 16 040, 15 968, 2485, 336 858 and 60 486 copies/microg DNA, respectively. Patients were treated by reduction or discontinuation of immunosuppressives and/or antiviral agents. The EBV DNA levels decreased in all these patients following the recovery from their symptoms. We encountered two cases of PTLD during this study period. One of them was referred to us after the onset of PTLD and one had been undergoing aggressive immunosuppression treatment for severe rejection. Both were successfully treated.

CONCLUSIONS

Serial quantitative analysis of the EBV genome load by means of real-time PCR are thought to be useful for preventing PTLD through adjustment of the immunosuppression level in response to the viral genome load following symptomatic EBV infection.

Higher intracerebral concentration of tacrolimus after intermittent than continuous administration to rats

Neurotoxicity associated with tacrolimus after liver transplantation is a serious problem. The optimal way to administer tacrolimus to reduce neurotoxicity remains to be clarified. Three groups of rats were administered tacrolimus for 2 weeks: group C, continuous intravenous infusion (0.25, 0.5, and 1.0 mg/kg/d); group I, intermittent intravenous bolus injection twice daily (0.25, 0.5, and 1.0 mg/kg/d); and group O, oral administration twice daily (5 mg/kg/d; n = 12 each). Rats were killed either day 7 or 14 to measure whole-blood and intracerebral trough concentrations of tacrolimus. The area under the whole-blood concentration-time curve (AUC) was determined day 7. The relative risk ratio of neurotoxicity was evaluated on the basis of the brain to blood concentration ratio (Kp) and intracerebral concentration to AUC ratio (R(AUC)). The whole-blood concentration of tacrolimus and AUC value were greater in group C than group I. Conversely, the intracerebral concentration and Kp and R(AUC) values were significantly greater in group I than group C. The difference in Kp values between groups C and I significantly increased with the dose and duration of administration. Whole-blood and intracerebral concentrations in group O were similar to those at the 0.25-mg/kg/d dose in group I. In conclusion, the intracerebral concentration of tacrolimus was greater after intermittent than continuous administration of the drug. Continuous administration of tacrolimus might be more advantageous than the intermittent method to reduce the intracerebral concentration and neurotoxicity.

Clinical implications of flow cytometry crossmatch with T or B cells in living donor liver transplantation

BACKGROUND

Acute allograft rejection (AR) in solid organ transplantation is generally regarded to develop through cell-mediated immune response following activation of helper T cells. Since production of antibodies is also mediated by helper T cells, humoral immunity may play some roles in AR. Although flow cytometry crossmatch (FCXM) is reported as a useful method for the detection of antibodies against donor antigen, specific role of T- or B-cell FCXM and its sensitivity for AR is controversial.

METHODS

T- and B-cell FCXM using fresh donor peripheral lymphocytes were performed before and after blood-type compatible living donor liver transplantation in 47 patients. IgM and IgG anti-donor antibodies were analyzed in relation to clinical AR.

RESULTS

Positive pre-transplant T-cell FCXM was associated with a high incidence of positive post-transplant T-cell FCXM (p=0.017). Four of five cases (80%) with positive pre-transplant T-cell FCXM experienced earlier AR (day 8.0+/-4.4, mean+/-SD) than 16 of 42 cases (31%) with negative pre-transplant T-cell FCXM (17.3+/-6.8; p=0.016). In addition, higher dose of steroids was given to treat AR episodes in cases with positive pre-transplant T-cell FCXM (79.9+/-10.3 mg/kg/month) than in those with negative pre-transplant T-cell FCXM (47.1+/-26.6; p=0.039). In the first month after transplantation, 13 episodes of positive post-transplant T-cell FCXM were all concomitant with or preceded clinical AR compared with seven ARs in T-cell FCXM-negative cases (p<0.0001). T-cell FCXM between positive sera and third parties revealed some crossreactions. In contrast, detection of antibodies by B-cell FCXM in pre- and post-transplant phases was scarcely associated with AR, and no correlation was found between T- and B-cell FCXM before and after transplantation.

CONCLUSIONS

Positive T-cell FCXM is closely related with AR and that before transplantation is a predictor of early and refractory AR as well as post-transplant FCXM. In contrast, not a few detections of antibodies irrelevant to AR are observed in B-cell FCXM, suggesting its low specificity.

Weaning of immunosuppression in living donor liver transplant recipients

BACKGROUND

Some reported studies have indicated the possibility of immunosuppression withdrawal in cadaveric liver transplantation. The aim of this study was to evaluate the possibility and feasibility of weaning living donor liver transplant recipients from immunosuppression.

METHODS

From June of 1990 to October of 1999, 63 patients were considered to be weaned from immunosuppression. They consisted of 26 electively weaned patients and 37 either forcibly or incidentally weaned patients (nonelective weaning) due to various causes but mainly due to infection. Regarding elective weaning, we gradually reduced the frequency of tacrolimus administration for patients who survived more than 2 years after transplantation, maintained a good graft function, and had no rejection episodes in the preceding 12 months. The frequency of administration was reduced from the conventional b.i.d. until the start of weaning to q.d., 4 times a week, 3 times a week, twice a week, once a week, twice a month, once a month, and finally, the patients were completely weaned off with each weaning period lasting from 3 to 6 months. The reduction method of nonelective weaning depended on the clinical course of each individual case. When the patients were clinically diagnosed to develop rejection during weaning, then such patients were treated by a reintroduction of tacrolimus or an additional steroid bolus when indicated.

RESULTS

Twenty-four patients (38.1%) achieved a complete withdrawal of tacrolimus with a median drug-free period of 23.5 months (range, 3-69 months). Twenty-three patients (36.5%) are still being weaned at various stages. Sixteen patients (25.4%) encountered rejection while weaning at median period of 9.5 months (range, 1-63 months) from the start of weaning. All 16 were easily treated with the reintroduction of tacrolimus or additional steroid bolus therapy.

CONCLUSIONS

We were able to achieve a complete withdrawal of immunosuppression in some selected patients. Although the mechanism of graft acceptance in these patients has yet to be elucidated, we believe that a majority of long-term patients undergoing living donor liver transplantation may, thus, be potential candidates to be successfully weaned from immunosuppression.

Microcirculatory changes in right lobe grafts in living-donor liver transplantation: a near-infrared spectrometry study

BACKGROUND

A continuing shortage of cadaveric liver even for adult patients has motivated not a few centers to proceed to living-donor liver transplantation using right lobe grafts. One of controversies is potential congestion in the graft anterior segment by the deprivation of the middle hepatic vein.

METHODS

Hepatic tissue oxygenation and hemoglobin concentration were investigated with a near-infrared spectroscopy in the course of harvesting and implantation in living-donor liver transplantation. Twenty adult recipients of right lobe graft were involved in the study. The aim of the analysis was to detect tissue congestion or ischemia.

RESULTS

No significant change in mean hepatic tissue oxygenation and hemoglobin was noted in the right lobe during donor operation even after hepatic parenchymal transection, although some trend for relative congestion, i.e., increased tissue hemoglobin, compared with the left lobe was observed. After graft reperfusion in the recipient, both mean hepatic tissue oxygen saturation and hemoglobin decreased significantly in the anterior segment, which was accompanied by increased heterogeneity of tissue hemoglobin and oxygenation. Increased heterogeneity of oxygenation and decreased tissue hemoglobin were observed also in the posterior segment.

CONCLUSIONS

The anterior segment in right lobe living-donor liver transplantation is sensitive to ischemia, rather than congestion, at least in the immediate phase after graft reperfusion. The anterior segment seems to be also more prone to circulatory disturbance than the other part of the graft.

Oral administration of tacrolimus in the presence of jejunostomy after liver transplantation

The feasibility of oral administration of tacrolimus in the presence of an intestinal stoma after liver transplantation (LTx) has not been adequately demonstrated. A 10-month-old girl underwent LTx with biliary reconstruction using a Roux-en Y loop. She developed intestinal perforation and underwent a jejunostomy at 40-50 cm distal to the jejunojejunostomy of the Roux-en Y loop on day 8 post-LTx. Tacrolimus was given twice daily via a nasogastric tube or orally; the initial dose of tacrolimus was 0.10 mg/kg/day. Until the time of intestinal perforation, the trough level of tacrolimus ranged from 13.0 to 19.6 ng/mL. The dose-normalized trough concentration (DNTC) of tacrolimus ranged from 130 to 196 ng.kg.day per mg.mL (control: 80-145 ng.kg.day per mg.mL). For a 2-week period when the patient was septic, the tacrolimus dose was reduced to 0.05 mg/kg/day, with a subsequent trough level of 3.6-5.1 ng/mL (DNTC: 72-102 ng.kg.day per mg.mL). After 3 weeks, the dose was increased to 0.175 mg/kg/day with the disappearance of infection; the trough level ranged from 8.5 to 9.7 ng/mL with a peak level of 26.3 ng/mL (DNTC: 48.5-55.4 ng.kg.day per mg.mL). After the initiation of oral feeding, the dose was slightly increased to 0.20 mg/kg/day with the trough level ranging from 8.1 to 9.8 ng/mL (DNTC: 40.5-49 ng.kg.day per mg.mL). After closure of the jejunostomy, the dose of tacrolimus was reduced to 0.075 mg/kg/day to maintain the same trough level (7.9-9.1 ng/mL) and the DNTC ranged from 105 to 121 ng.kg.day per mg.mL. In conclusion, oral administration of tacrolimus may achieve the therapeutic level, even in the presence of jejunostomy after LTx, although the bioavailability is decreased.

Analysis of alloreactivity and intragraft cytokine profiles in living donor liver transplant recipients with graft acceptance

Although some previous studies have indicated the possibility of immunosuppression withdrawal in clinical liver transplantation, the mechanism of graft acceptance is not clear. The aim of this study is to elucidate the alloreactivity against the donor and intragraft cytokine profiles in living donor liver transplant (LDLT) recipients with graft acceptance. In October 1999, we had 23 patients who survived without immunosuppression after LDLT with a median drug-free period of 25 months (range: 3-69 months). They consisted of six patients who were electively weaned by an elective weaning protocol and 17 either forcibly or accidentally weaned patients due to various causes but mainly due to infection. We evaluated the alloreactivity against the donor in these patients by a mixed lymphocyte reaction and intragraft cytokine profiles by real-time reverse transcriptase-polymerase chain reaction. The development of donor-specific hyporeactivity was observed in the patients with graft acceptance. The cytokine pattern in the supernatant of the culture medium revealed a down regulation of T helper (Th) 1 cytokine INF gamma against the donor while no significant difference was seen in Th2 cytokine IL-10. Regarding the intragraft cytokine profiles, we could find no amplification of Thl cytokines (IL-2, INF y) and IL-4 while some of the patients revealed a gene expression of IL-10 with no significant difference from that of the normal, untransplanted liver specimen. In addition, no difference was observed in any other cytokines (IL-1beta, IL-8, IL-15, TNFalpha) compared with those of the normal controls. We propose that the down regulation of Th1 cytokine is one possible mechanism of graft acceptance in LDLT recipients.

Population pharmacokinetics of tacrolimus in Asian paediatric liver transplant patients

AIMS

The purpose of this study was to describe the population pharmacokinetics of intravenous and oral tacrolimus (FK506) in 20 Asian paediatric patients, aged 1-14 years, following liver transplantation and to identify possible relationships between clinical covariates and population parameter estimates.

METHODS

Details of drug dosage histories, sampling times and concentrations were collected retrospectively from routine therapeutic drug monitoring data accumulated for at least 4 days after surgery. Before analysis, patients were randomly allocated to either the population data set (n = 16) or a validation data set (n = 4). The population data set was comprised of 771 concentration measurements of patients admitted over the last 3 years. Population modelling using the nonlinear mixed-effects model (NONMEM) program was performed on the population data set, using a one-compartment model with first-order absorption and elimination. Population average parameter estimates of clearance (CL), volume of distribution (V) and oral bioavailability (F) were sought; a number of clinical and demographic variables were tested for their influence on these parameters.

RESULTS

The final optimal population models related clearance to age, volume of distribution to body surface area and bioavailability to body weight and total bilirubin concentration. Predictive performance of this model evaluated using the validation data set, which comprised 86 concentrations, showed insignificant bias between observed and model-predicted blood tacrolimus concentrations. A final analysis performed in all 20 patients identified the following relationships: CL (l h-1) = 1.46 *[1 + 0. 339 * (AGE (years) -2.25)]; V (l) = 39.1 *[1 + 4.57 * (BSA (m2)-0. 49)]; F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] and F = 0.197 *[1 + 0.0887 * (WT (kg) -11.4)] * [1.61], if the total bilirubin > or = 200 micromol l-1. The interpatient variabilities (CV%) in CL, V and F were 33.5%, 33.0% and 24.1%, respectively. The intrapatient variability (s.d.) among observed and model-predicted blood concentrations was 5.79 ng ml-1.

CONCLUSIONS

In this study, the estimates of the pharmacokinetic parameters of tacrolimus agreed with those obtained from conventional pharmacokinetic studies. It also identified significant relationships in Asian paediatric liver transplant patients between the pharmacokinetics of tacrolimus and developmental characteristics of the patients.

Manganese deposition in the globus pallidus in patients with biliary atresia

BACKGROUND

Chronic liver diseases may alter trace element contents in the brain. Among these trace elements, manganese is a ubiquitous transition metal excreted by the liver into the bile. Blood concentrations of manganese are elevated in patients with biliary atresia who have undergone hepatic portoenterostomy. The present study investigated the effects of liver transplantation on manganese deposition in the brain in such patients.

METHODS

The signal intensity of the globus pallidus was calculated as an index defined as the percentile ratio of signal intensity in the globus pallidus to the subcortical frontal white-matter in sagittal T1-weighted magnetic resonance imaging planes.

RESULTS

Brain magnetic resonance imaging revealed hyperintense signals in the globus pallidus due to manganese deposition in biliary atresia patients. Few neurologic symptoms related to manganese intoxication were observed. However, one 23-year-old female with biliary atresia had depressive symptoms and dyskinesia; she improved after oral administration of the dopamine precursor, L-DOPA. Manganese deposition disappeared in two patients after living-related reduced-size hepatic transplantation.

CONCLUSIONS

Manganese accumulates in the brain during cholestasis associated with biliary atresia and disappears after hepatic transplantation. Manganese deposition is likely to be subclinical and reversible but may be associated with some age-related neurologic symptoms.

A 12-day course of FK506 allows long-term acceptance of semi-identical liver allograft in inbred miniature swine

BACKGROUND

Spontaneous tolerance to liver allograft has been reported previously in outbred pig models, but the lack of genetic background did not allow to analyze the impact of the major histocompatibility complex (MHC) on tolerance induction. A model of semi-identical liver allograft was therefore developed in inbred miniature swine in order to mimic the clinical situation of living related liver transplant (parent into infant) and to study a protocol for inducing tolerance to liver allograft.

METHODS

SLAdd (class Id/d, class IId/d) pigs received orthotopic liver allograft from heterozygous SLAcd (class Ic/d, class IIc/d) miniature swine. Eight animals did not receive immunosuppression. Fourteen SLAdd animals had a 12-day course of FK506 and were divided in two subgroups. In subgroup FK-1, six pigs received a daily intramuscular injection of FK506 at 0.1-0.4 mg/kg, in order to reach daily trough levels between 7 and 20 ng/ml; in subgroup FK-2, eight additional animals received two daily injections of FK506 at 0.05 mg/kg regardless of the daily trough levels. Graft survival, liver biological tests, histology, cellular and humoral immune responses, as well as detection of microchimerism were assessed in all groups.

RESULTS

All untreated animals rejected their allograft and died within 28.1 +/- 9.5 days. These rejector animals developed a significant anti-donor cellular and humoral immune response. No peripheral or lymphoid tissue microchimerism was detected in this group. In contrast, long-term survival was obtained in five FK-treated animals (112, 154, 406, 413, and 440 days), whereas several pigs died with a normal allograft function from either overimmunosuppression or intercurrent causes. All FK-treated pigs developed a specific anti-donor unresponsiveness in both cell mediated lymphocytotoxicity and mixed lymphocyte reaction and did not develop anti-donor alloantibodies. The study of the anti-donor immune response by mixed lymphocyte reaction, during the first postoperative week, demonstrated a specific anti-donor unresponsiveness in the peripheral blood from the first posttransplant day. Although microchimerism was detectable in the peripheral blood for several postoperative weeks (maximum 10 weeks) in FK-treated animals, donor cells or DNA were not detected during the long-term follow-up in peripheral blood or lymphoid tissues.

CONCLUSIONS

Spontaneous tolerance to semi-identical orthotopic liver allograft did not occur, whereas a 12-day course of FK506 allowed long-term graft acceptance. All FK-treated animals developed in vitro signs of specific immune unresponsiveness and transient peripheral microchimerism. The specific anti-donor cellular unresponsiveness occurred on the first postoperative day after surgery and was of long-term duration. The study of the early immunological events in this model could be of major importance regarding clinical living related liver transplantation.

Tacrolimus: a further update of its pharmacology and therapeutic use in the management of organ transplantation

Tacrolimus (FK-506) is an immunosuppressant agent that acts by a variety of different mechanisms which include inhibition of calcineurin. It is used as a therapeutic alternative to cyclosporin, and therefore represents a cornerstone of immunosuppressive therapy in organ transplant recipients. Tacrolimus is now well established for primary immunosuppression in liver and kidney transplantation, and experience with its use in other types of solid organ transplantation, including heart, lung, pancreas and intestinal, as well as its use for the prevention of graft-versus-host disease in allogeneic bone marrow transplantation (BMT), is rapidly accumulating. Large randomised nonblind multicentre studies conducted in the US and Europe in both liver and kidney transplantation showed similar patient and graft survival rates between treatment groups (although rates were numerically higher with tacrolimus- versus cyclosporin-based immunosuppression in adults with liver transplants), and a consistent statistically significant advantage for tacrolimus with respect to acute rejection rate. Chronic rejection rates were also significantly lower with tacrolimus in a large randomised liver transplantation trial, and a trend towards a lower rate of chronic rejection was noted with tacrolimus in a large multicentre renal transplantation study. In general, a similar trend in overall efficacy has been demonstrated in a number of additional clinical trials comparing tacrolimus- with cyclosporin-based immunosuppression in various types of transplantation. One notable exception is in BMT, where a large randomised trial showed significantly better 2-year patient survival with cyclosporin over tacrolimus, which was primarily attributed to patients with advanced haematological malignancies at the time of (matched sibling donor) BMT. These survival results in BMT require further elucidation. Tacrolimus has also demonstrated efficacy in various types of transplantation as rescue therapy in patients who experience persistent acute rejection (or significant adverse effect's) with cyclosporin-based therapy, whereas cyclosporin has not demonstrated a similar capacity to reverse refractory acute rejection. A corticosteroid-sparing effect has been demonstrated in several studies with tacrolimus, which may be a particularly useful consideration in children receiving transplants. The differences in the tolerability profiles of tacrolimus and cyclosporin may well be an influential factor in selecting the optimal treatment for patients undergoing organ transplantation. Although both drugs have a similar degree of nephrotoxicity, cyclosporin has a higher incidence of significant hypertension, hypercholesterolaemia, hirsutism and gingival hyperplasia, while tacrolimus has a higher incidence of diabetes mellitus, some types of neurotoxicity (e.g. tremor, paraesthesia), diarrhoea and alopecia.

CONCLUSION

Tacrolimus is an important therapeutic option for the optimal individualisation of immunosuppressive therapy in transplant recipients.

Right lobe graft in living donor liver transplantation

BACKGROUND

For the sake of donor safety in living donor liver transplantation (LDLT), the left lobe is currently being used most often for the graft. However, size mismatch has been a major obstacle for an expansion of the indication for LDLT to larger-size recipients, because a left lobe graft is not safe enough for them.

METHODS

In 1998, LDLT using a right lobe graft was introduced and performed on 26 recipients to overcome the small-for-size problem. The right lobe, which does not include the middle hepatic vein of the donor, was used. Initially, indication for right lobe LDLT was basically defined as an estimated left lobe graft volume/recipient body weight ratio (GRWR) of <0.8%, which was later raised to <1.0%.

RESULTS

All the donors recovered from the operation without persistent complications. Two donors with transient bile leakage were successfully treated with a conservative approach. A right lobectomy resulted in more blood loss (337+/-175 ml), and a longer operative time (6.67+/-0.85 hr) than a lateral segmentectomy, but not a left lobectomy. Grafts with a GRWR >0.8% were implanted in all recipients, except for two, who received relatively smaller right lobes (GRWR of 0.68% and 0.66%). In one of these two, the right lobe from the donor was used as the orthotopic auxiliary graft. Postoperative transitory increases in total bilirubin and aspartate transaminoferase for right lobe donors were higher than those for the left lateral segmentectomy. Nineteen recipients (73.1%) were successfully treated with this procedure. The causes of death were not specific for right lobe LDLT, except for one patient with a graft that had multiple hepatic venous orifices. These multiple and separate anastomoses of the hepatic veins caused an outflow block as a result of a positional shift of the graft, which finally led to graft loss.

CONCLUSION

Our experience suggests that right lobe grafting is a safe and effective procedure, resulting in the expansion of the indication for LDLT to large-size recipients. How to deal with the possible variation in the anatomy of the right lobe graft should be given attention throughout the procedure.

Severe late acute allograft rejection in a child after living-related auxiliary partial orthotopic liver transplantation for ornithine transcarbamylase deficiency

Auxiliary liver transplantation (ALT) is known to correct liver-based metabolic disorders. However, it remains unclear whether the presence of a native liver influences the long-term prognosis of ALT for metabolic diseases. We reported on a 4-yr-old girl who had undergone living-related auxiliary partial orthotopic liver transplantation (APOLT) for ornithine transcarbamylase deficiency and experienced severe late acute rejection 18 months after liver transplantation, during weaning of immunosuppressive agents. Results of histological analysis of the graft indicated very severe acute rejection (rejection activity index, 9/9), and computed tomography revealed graft liver atrophy. These observations suggest the possibility that severe rejection might occur in APOLT, especially during weaning of immunosuppression.

Living related liver transplantation from heterozygote genetic carriers to children with Wilson's disease

We reviewed the outcome of children undergoing living related liver transplantation (LRLT) for Wilson's disease (WD), and specifically addressed the potential risk associated with the use of donors who were heterozygous for the Wilson genetic defect. LRLTs were carried out in 11 children with WD, nine of whom presented with fulminant hepatic failure and two with end-stage hepatic insufficiency. The age of the patients ranged from 6 to 16 yr. Eight patients had hepatic encephalopathy and were plasmapheresed preoperatively. The donors (all parents: six fathers and five mothers) were all one-haplotype matched with their respective recipients, and were all therefore heterozygote carriers of the WD genetic defect. The serum ceruloplasmin levels were within normal limits in all donors (mean: 20.0 +/- 2.85 mg/dL). All recipients but one had low serum ceruloplasmin levels with a mean value of 11.6 +/- 7.36 mg/dL before transplantation. The serum ceruloplasmin levels had increased to an average of 21.0 +/- 3.76 mg/dL after LRLT at the latest evaluation, which ranged between 7 and 75 months after transplantation. A marked reduction in urinary copper excretion was observed in all recipients after transplantation. Of eight recipients presenting preoperatively with Kayser-Fleischer (K-F) rings, this abnormality resolved completely after LRLT in five patients and partially in three. All recipients are alive and remain well, and none have developed signs of recurrent WD after a mean follow-up period of 31 months (range 7-75 months). In conclusion, LRLT is an excellent choice for effective treatment of WD, and grafts chosen from heterozygote carriers of the condition do not appear to confer any risk of recurrence in the recipients.

Auxiliary partial orthotopic living donor liver transplantation as an aid for small-for-size grafts in larger recipients

BACKGROUND

In countries where living donors are the only source of liver grafts, restrictions on graft size are a serious obstacle for the expansion of indications for adult recipients. To overcome this problem, auxiliary partial orthotopic liver transplants (APOLT*) was performed on the basis of the concept that the residual native liver would support the graft function until the graft had grown enough to function by itself.

METHODS

APOLT as an aid for small-for-size (SFS) grafts was reviewed retrospectively to evaluate its feasibility. Between April 1995 and March 1998, 20 recipients underwent APOLT, which was indicated because of a SFS graft in 15 of them. The indication was based on the estimated graft/recipient's body weight ratio (GRWR). If the ratio was <0.8%, APOLT was performed. The other 5 patients had a graft with a GRWR >0.8% and underwent APOLT on the basis of the residual native liver supporting the graft function temporarily, 4 for supplementation of the defective enzyme in metabolic liver diseases and one for leaving the potential of the regeneration of the native liver in fulminant hepatic failure. The recipients who underwent APOLT because of a SFS graft were categorized as the SFS group, and the others were the second group.

RESULTS

In the SFS group, the age of the recipients ranged from 13 to 48 (median 23). The original indications of this group were fulminant hepatic failure in 2 recipients, acute deterioration of chronic liver diseases in 3, Wilson's disease in 2, biliary atresia in 4, primary biliary cirrhosis in 3, and primary sclerosing cholangitis (PSC) in one. The actual GRWR ranged from 0.45 to 0.72 (median 0.55). The graft was implanted after resection of the left lateral segment of the native liver. Except in the first two patients, the portal vein to the residual native liver was completely transected so that all of the portal blood drained into the graft liver. This procedure was successful in 9 patients. The cause of death in the other 6 was mainly infection. The mortality rate among the recipients with signs of advanced liver failure, such as massive ascites or hepatic coma, was higher, even though APOLT was used to support the SFS graft. In the second group, in the other five recipients who underwent APOLT for other indications, one recipient with fulminant hepatic failure died of sepsis caused by the dehiscence of bilio-enteric anastomosis.

CONCLUSIONS

APOLT as an aid for a SFS graft is technically viable. This procedure can thus expand the indication of living donor liver transplants for adult recipients when the native liver retains some functional capability to support the grafted liver during the immediate postoperative period.

Pediatric liver transplantation with cadaveric or living related donors: comparative results in 90 elective recipients of primary grafts

STUDY DESIGN

Between July 1993 and March 1997, 110 children were listed for primary elective liver transplantation with cadaveric (Cad: n = 68) or living-related (LR: n = 42) donors. Pregraft mortality, post-transplant survival, and surgical and immunologic complications were retrospectively compared in both groups.

RESULTS

The pregraft mortality rate was 10 (15%) of 68 versus 1 (2%) of 42 in the Cad and LR groups, respectively (P =.049). Postliver transplantation 1-year patient and graft survival rates were 87% and 75% in the Cad group (n = 49) versus 92% and 90% in the LR group (n = 41), respectively (NS). The incidence of post-transplant complications was as follows: hepatic artery thrombosis (Cad: 16%; LR: 0%, P =.020), portal vein thrombosis (Cad: 8%; LR: 2%, NS), and biliary complications (Cad: 14%; LR: 34%, P =.044). The overall incidence of acute rejection was similar in both groups; however, a lower incidence of acute rejection occurred in LR graft recipients treated with tacrolimus.

CONCLUSIONS

The introduction of an LR donor liver transplantation program allowed a significant decrease in the pretransplant mortality rate, with a consequent overall improvement in patient survival compared with the Cad series. The incidence of biliary complications was higher in the LR series, whereas better human leukocyte antigen matching in this subgroup did not result in a lower rejection incidence.

Postoperative flow cytometry crossmatch in living donor liver transplantation: clinical significance of humoral immunity in acute rejection

BACKGROUND

The role of humoral immunity in acute rejection in solid organ transplantation remains controversial, although it is known that the presence of antidonor antibodies may precipitate graft rejection. We investigated the clinical relevance of antidonor humoral immunity for living donor liver transplantation (LDLT) by means of flow cytometry crossmatch (FCXM).

METHODS

T cell FCXM using fresh donor peripheral lymphocytes was performed before and up to 1 month after LDLT in 58 patients. Ten patients received ABO-incompatible grafts. IgM and IgG antidonor antibodies were analyzed in relation to clinical acute rejection as defined by liver function tests with or without histological evidence.

RESULTS

Pretransplantation FCXM was positive for five patients (8.6%), resulting in two cases of positive posttransplantation FCXM and two rejection episodes. Twelve patients (20.7%) showed positive posttransplantation FCXM. The incidence of acute rejection within 1 month was 100% in FCXM-positive patients and 17.4% in FCXM-negative patients (P<0.001). Thirteen (76.5%) of 17 rejection episodes in ABO-compatible cases were associated with concomitant antidonor IgM antibody. IgG antibody was also identified in six of these episodes. Antidonor antibodies disappeared after rejection treatments in all cases, but with some delay in clinical improvement. On the other hand, no antidonor antibodies were detected in any of the four rejection episodes in ABO-incompatible cases.

CONCLUSIONS

Early acute rejection in LDLT is significantly associated with antidonor T cell antibody formation in ABO-compatible cases. This suggests a definite role for donor-specific humoral immunity in acute rejection. Rejection episodes without antidonor antibodies may suggest graft injury by pure cellular immunity, or possibly the presence of humoral immunity triggered by antigens not present on donor T cells.