Prospective analysis between the therapy of immunosuppressive medication and allogeneic microchimerism after liver transplantation

After liver transplantation, migration of donor-derived hematopoietic cells to recipient can be detected in peripheral blood. This state is termed microchimerism. The aim of this study was to investigate prospectively the presence of allogeneic microchimerism, the occurrence of acute cellular rejection and the level of immunosuppression in transplanted patients. Microchimerism occurrence between 10 days and 12 months after liver transplantation was analyzed in 47 patients aged between 15 and 65 by a two-stage nested PCR/SSP technique to detect donor MHC HLA-DR gene specifically. A pre-transplant blood sample was collected from each patient to serve as individual negative control. Microchimerism was demonstrated in 32 (68%) of the 47 patients; of these, only 10 patients (31.2%) presented rejection. Early microchimerism was observed in 25 patients (78.12%) and late microchimerism in 7 patients (21.8%). Among the patients with microchimerism, 14 were given CyA and 18 were given FK506. In the group without microchimerism, 12 patients were given CyA and 03 were given FK506. There was a significant association between the presence of microchimerism and the absence of rejection (p=0.02) and also between microchimerism and the type of immunosuppression used. Our data indicate that microchimerism and probably differentiation of donor-derived leukocytes can have relevant immunologic effects both in terms of sensitization of recipient and in terms of immunomodulation toward tolerance induction.

Expanded Milan criteria on pathological examination after liver transplantation: analysis of preoperative data

BACKGROUND

We sought to evaluate the accuracy of imaging techniques related to the Milan criteria (MC) compared with the explant histology and the survival of these patients.

METHODS

Between 1997 and 2006, we selected 45 cirrhotic patients with hepatocellular carcinoma distributed into two groups according to explant histology: MC and Expanded Milan Criteria (EMC). Age, gender, preoperative imaging (ultrasound [US] and/or computed tomography [CT]), maximal tumor dimension, number of tumors, explanted histology, histology degree, alpha-fetoprotein (AFP) level and vascular invasion were compared among the patients to evaluate the value of these prognostic factors for survival after liver transplantation.

RESULTS

By histology 42.2% explants were identified as EMC. The mean AFP level was 204.5 ng/mL. Vascular invasion was detected in 31.5% of explants and 68.4% showed incidental tumors. The survival rates after 10 years were 47.4% whereas MC patients showed 57.77%. The mean AFP level among MC patients was 150.2 ng/mL with vascular invasion detected in 7.7% of explants, and 47.4% with incidental tumors. The overall sensitivity of the imaging techniques was 83.3% for CT and 75% for US. The specificity was 96% for CT and 80.1% for US.

CONCLUSION

Scan examinations in the preoperative evaluation underestimated about 42.2% of tumors. Those patients had vascular invasion but the survival after 10 years was similar between the ECM and MC groups.

Intraoperative massive transfusion decreases survival after liver transplantation

Patients undergoing liver transplantation often experience coagulopathy and massive intraoperative blood loss that can lead to morbidity and reduced survival. The aim of this study was to verify the survival rate and discover predictive factors for death among liver transplant patients who received massive intraoperative blood transfusions. This cohort study was based on prospective data collected retrospectively from January 2004 to July 2006. The 232 patients were distributed according to their blood requirements, (namely, more or less than 6 units), including red blood cell saver. The statistical analyses were performed using Student t test, Cox hazard regression, and the Kaplan-Meier method (log-rank test). The massively transfused cohort displayed higher Child-Pugh classifications (10.2 vs 9.6; P = .03); model for end-stage liver disease (MELD) scores (19 vs 17; P = .02); recipient weights (75.4 vs 71 kg; P = .03); as well as warm ischemia times (70.7 vs 56.4 minutes; P < .001) and surgery times (584.6 vs 503.4 minutes; P < .05). The proportional hazard (Cox) regression analysis showed that the risk of death increased 2.1% for each unit of donor sodium and 1.6% for each additional year of donors age over 50. The survival rates at 6, 12, 60, and 120 months for > or = 6 vs <6 U of blood transfusion of 63.8% vs 83.3%; 53.9% vs 76.3%; 40% vs 60%; 34.5% vs 49.2%. In conclusion, we observed that patients receiving over 6 red blood cell units intraoperatively displayed reduced survival. Predictive factors for this risk factor were high donor level of sodium and of age.

De novo posttransplantation nonlymphoproliferative malignancies in liver transplant recipients

The risk of developing de novo malignancies after liver transplantation is around 1% per year. The incidence varies from 3% to 15%; it is greater than that in the general population. The potential causes for cancer after solid organ grafting are: chronic immunosuppression and human herpes viral infection. The objective of this paper was to review the medical literature about the subject to verify the incidence of de novo malignancies in our service. We performed retrospective analysis of the medical files of 325 successive patients undergoing orthotopic liver transplantation from September 1991 to December 2006. We analyzed the type of tumor, the risk factors, the treatment modality, and the patient survivals. Recurrences of hepatocellular carcinoma were excluded. There were 5 (1.54%) men of average age 50.2 years, and an 80% mortality rate. Their survival time was affected by the nature of the tumor and by the late manifestations of intestinal obstruction allowing adequate surgical treatment. Four of the patients displayed heavy alcohol and tobacco consumption before transplantation. Screening for premalignant lesions must be strongly encouraged to achieve better postoperative results.

Molecular Mechanisms Associated With Donor-Specific Microchimerism in Peripheral Blood of Brazilian Patients After Liver Transplantation

A large number of studies in liver transplantation have demonstrated allogeneic microchimerism. The clinical and immunologic implications of this finding remain inconclusive, just as the influence of HLA mismatch and donor alloreactivity also are controversial. The present study analyzed the presence of allogeneic microchimerism in liver transplant recipients in relation to donor leukocyte kinetics and rejection episodes. The study was extended to determining the influence of immunogenetic factors in patients after liver transplantation. The presence of allogeneic microchimerism was analyzed on peripheral blood of 50 recipients. DNA extracted from the samples was subjected to typing for HLA-DRB1 and -DQB1 alleles by polymerase chain reactions using sequence-specific primers (PCR/SSP). Microchimerism was identified by nested PCR/SSP. Microchimerism was detected in 72% of patients. There was significant effect of microchimerism on rejection episodes (P=.002), while HLA mismatches did not show significance for one or two mismatches (P=.98). Allogeneic microchimerism detected in the majority of liver transplant patients was observed to be significantly associated with rejection episodes.

Liver transplant recipients mortality on the waiting list: long-term comparison to Child-Pugh classification and MELD

We sought to evaluate our experience concerning the high waiting list mortality rate for orthotopic liver transplantation (OLT) using the MELD (Model for End-Stage Liver Disease), which has been shown to predict short-term survival better than Child-Turcotte-Pugh (CTP) classification. The predominant end-stage disease was cirrhosis due to hepatitis C virus (67%), patient mean age was 36.8 years, and 72.1% were men. When the patients were included on a waiting list, the MELD score was stratified into W: 0 to 10; X: 11 to 20, and Y: 21 to 40 and the CPT as A: 5 to 6, B: 7 to 9, and C: 10 to 15. It was also observed that 77.8% of patients were on the waiting list, 16.4% underwent OLT and 5.8% had been removed. The estimated survival rate after 1 year was W = 85.4%; X = 83.3%, Y = 46.8%; A = 81.3%, B = 84.2%, C = 45.9%. Child median score was 8 +/- 1.5 (5 to 15) and the MELD was 14.7 +/- 5.1 (8 to 43). The mortality rate was 20.2%. Severe patients classified as Y or C showed greater mortality than the other groups (P <.001), but no significant difference between Y and C strata. The mortality rate was the same as in previous years.

Role of Choledochojejunostomy in Liver Transplantation

AIM

This study analyzes the efficacy and rate of complications related to Roux-en-Y choledochojejunostomy need either as the primary biliary reconstruction during orthotopic liver transplantation (OLT) or to treat biliary complications.

METHODS

One hundred seventy-seven transplantation procedures were performed from September 1991 to December 2003 in recipients of mean age 51.9 years. Patients were reviewed for the type of biliary reconstruction, the prevalence of biliary complications, and the choice of treatment for these complications. Duct-to-duct anastomosis (group CDC) was performed in 153 patients (85.6%), and choledochojejunostomy (group CDJ) in 24 patients (14.4%). Biliary complications, including stenosis, bile leakage, calculosis, and extensive biliary necrosis, required hospitalization, surgical interventions or endoscopic approaches. Biliary complications in the CDC group first were addressed by endoscopic treatments. When endoscopic therapy failed, they were approached by surgical reintervention. All biliary complications in group CDJ were surgically treated, namely, revision of the Roux-en-Y choledochojejunostomy. The chi square test was used to compare frequencies, with Yates correction when necessary; P values were considered significant at <.05. The Mann-Whitney U test was used to evaluate survival.

RESULTS

Fifty-eight (32.8%) biliary complications in 47 patients required endoscopic or surgical approaches. In group CDJ, 1 patient had bile leakage requiring surgical treatment. The prevalence of biliary complications was lower in the CDJ group than the CDC group (P < .05). Endoscopic treatment applied in 23 patients, failed in 11. Surgical approaches were performed in 11 patients after endoscopic failure, and in 13 patients as the first option to treat biliary complications. No failure was observed with surgical treatment. Cholangitis occurred in 3 patients who received surgical treatment and 4 patients who received endoscopic treatment. There was no statistically significant difference when comparing the mortality rates of the 3 types of treatment for biliary complications: endoscopy, surgery, and endoscopy followed by surgery. Survival rates were similar for the 3 types of treatment of biliary complications.

CONCLUSION

Roux-en-Y choledochojejunostomy is a useful tool to treat biliary complications after OLT, especially when endoscopic treatment fails. In our experience, the rate of complications directly related to this technique is significantly lower than common duct anestomosis, whether used for biliary reconstruction during OLT or for posttransplantation biliary complications.

Development of donor-specific microchimerism in liver transplant recipient with HLA-DRB1 and -DQB1 mismatch related to rejection episodes

Migration of donor-derived cells to recipient tissues after liver transplantation has been suggested as a mechanism to induce and maintain allograft tolerance, although important issues remain including acute rejection posttransplantation mortality, and complications related to immunosuppressive therapy. We therefore examined the relation of rejection to chimerism based upon recipient and donor mismatch of HLA-DRB1 and -DQB1 alleles. Laboratory analysis of peripheral blood was performed before and 10 days to 16 months after liver transplantation in 32 recipients, using ganglion or spleen cell samples of respective donors. DNA was extracted for HLA-DRB1 and DQB1 allele typing using polymerase chain reactions with sequence-specific primers (PCR-SSP). Microchimerism was analyzed through nested PCR. Our results confirmed that patients with one or two mismatched HLA-DRB1 and-DQB1 alleles showed microchimerism and no rejection (P <.05). Microchimerism was present in 71.88% of the patients, and a significant association of rejection P <.05 was found when microchimerism was correlated to graft rejection. These results suggest that the presence of microchimerism may be associated with acceptance, tolerance and survival of the allograft.

Late hepatic artery thrombosis after liver transplantation: clinical setting and risk factors

The aim of this study was to assess the prevalence clinical presentation, and impact on outcome of late hepatic artery thrombosis (HAT) after OLT. We also sought risk factors other than technical problems that predispose to the pathogenesis of late HAT among 178 OLT performed from 1999 to 2002. Late HAT was diagnosed using Doppler ultrasonography and arteriography. Late HAT was observed in nine patients (3.8%), all of whom had experienced chronic HCV infection. Median time to HAT diagnosis was 4.88 months after OLT. Mean follow-up time was 40.25 months. Recipient age ranged from 30 to 61 years and median donor age, 28 years. Mean warm ischemia time was 63 minutes and mean cold ischemia time, 660 minutes. All of our study group were cigarette smokers. Postoperative CMV infection, presenting with hepatitis, had been treated in 55.6%. Before the diagnosis of HAT more than one episode of acute cellular rejection had been observed in six patients (55.6%) and 44.5% had chronic rejection. The diagnosis of CR was established after the diagnosis of HAT in all cases. Recurrence of HCV infection was histologically documented in 44.5%. Only one patient experienced graft loss (77 months after OLT). Six of nine patients had biliary complications, treated either by endoscopic stenting or by surgical drainage. Two patients were asymptomatic. In conclusion, late HAT shows a benign presentation that has no impact on graft survival. Possible risk factors have yet to be defined by multicenter trials.

[Indication and results of liver transplantation in adults]

Increase of survival of patients submitted to transplantation is much superior when compared to other treatments in patients suffering terminal chronic hepatic failure. This fact has been allowing earlier indication of hepatic transplantation in lower operative risk patients. Pre-operative cardiocirculatory evaluation is essential, because during surgery hemodynamic and cardiac output alterations shall occur. The actual survival above 75% suggests that it is easier nowadays to look for factors responsible for mortality than to those predictable by survival. Postoperative survival analysis shows better results in cholestatic diseases (primary biliary cirrhosis and sclerosing cholangitis). Regarding hepatocelular carcinoma over cirrhotic liver, the best results are detected in small lesions up to 3 cm.