Study On Prophylaxis And Management Of HBV Recurrence After Liver Transplantation

Hepatitis B infection remains a major health problem in many regions around the world. An estimated 350 million people worldwide carry the hepatitis B virus (HBV) and about 5% of those who become infected will die as a consequence of cirrhosis (severe liver scarring) and liver cancer. In china, the carrier rates for chronic hepatitis B infection range about from 10% to 20%. Chronic hepatitis B virus (HBV) infection has already become a common cause of decompensated end-stage liver disease. A liver transplant operation is often the only option left open to doctors treating patients with life-threatening liver damage induced by hepatitis B. hepatitis B virus-infection patients form a large indication for orthotopic liver transplantation (OLT). However, the recurrence of HBV in patients transplanted for chronic hepatitis B is almost universal and is associated with poor survival rates. It is urgent for us to find an effective prophylaxis and treatment plan for the patients with HBV recurrence.Oral nucleoside analogues plus IM hepatitis B immunoglobulin (HBIg), which is regard as "golden standard" for the prophylaxis of HBV recurrence, also has some limitations. For example, long-term HBIg and/or lamivudine (LAM) administration reduces the rate of HBV recurrence but it should result in the selection of HBV mutants, as the mutations in HBV HBsAg genome or the tyrosine-methionine-aspartate-aspartate (YMDD) locus of the HBV polymerase gene respectively. The research for the optimal prophylaxis and treatment of HBV recurrence is never to stop.Quasispecies are a conception that is used to describe the genetic heterogeneity of same organism, which was first advanced by Eigen. In the research field of virology, quasispecies are used to describe the heterogeneity of same virus in an infected individuality. HBV quasispecies have detected in patients with chronic hepatitis B. It has reported that HBV quasispecies heterogeneity can influence the response to anti-virus treatment (IFN or nucleoside analogues). We have completed the research about the HBV quasispecies forming and changing in OLT patients pre- and post-operation. To date, there have no reports about the HBV quasispecies forming and changing under the nucleoside analogues selective pressure pre-OLT and it's reinfection on HBV recurrence after OLT.The pathogenesis of chronic hepatitis B is not well understood. The cellular immune response is thought to be critical in determining the outcome of infection in terms of both viral clearance and liver cell injury, and antigen-specific-CTL is the key factor. Therefore, understanding the antigen-specific immune response against HBV is important for the development of successful therapy and vaccine for this serious public health problem. Low antigen-specific-CTL immune response is thought to be main reason for chronic hepatitis B. However, it is not well understand the quantity and function of HBV antigen-specific-CTL in OLT patients which is under immunosuppression and with major histocompatibility complex variability between the donor and recipient. The pentamer technology is a powerful tool in researching on antigen-specific T cells, regardless of their function after in vivo or in vitro antigen stimulation, and without the need of in vitro expansion, it have greatly enhanced the opportunities for directly studying antigen-specific T cells.Based on the research mentioned above, we collect and analyze retrospectively the clinic data of OLT patients who take the operation in our hospital. Direct PCR sequencing was used to detect 394 bp nucleotide of HBV RT region to study HBV quasispecies influence pre-OLT and Pentamer technology was used to HBV antigen-specific-CTL in order to provided some theoretical clues for the prophylaxis and treatment of the patients with HBV recurrence.The main research results are as follows:1. To May 31, 2007, there were 116 patients died in the all 297 OLT patients. Death rate is 46.9% in HCC patients and nearly all cause of death were cancer recurrence. However, the death rate of non-HCC patients is 31.6% and many people died around the operation.2. There were 26 HBV recurrence OLT patients and the recurrence rate is 9.4%. The median time of recurrence is 14 months. 17 YMDD mutant HBV recurrence cases were HBV DNA positive pre-OLT while only 6 cases were negative. 3 cases were wild-type HBV recurrence caused by bad compliance.3. The HBV recurrence rate of group with serum HBV DNA positive pre-OLT was much higher than the HBV DNA negative group and step up with HBV DNA level ascensus. In the serum HBV DNA positive patients, the recurrence rate of LAM + HBIg prophylaxis group was much lower than the LAM monotherapy group. But there were no difference between the 2 groups in the serum HBV DNA negative patients.4. ADV was administered to 23 patient who developed LAM-resistant HBV recurrence and LAM treatment was continued for 3 wild-type HBV recurrence patients. Serum HBV DNA negative and liver function normalization in 24 patients were observed after 2 or 3 months treatment while 1 patient after 13 months. There is only 1 patient whose serum HBV DNA negative were observed after 24 months with ADV+LAM treatment. During the treatment, ADV and LAM were well tolerated, without side effects.5. After 59 times ALSS treatment among the 30 OLT patients, the clinical symptoms and signs of all patients were ameliorated at median 3d (1-153d), while the liver and kidney function were improved dramatically. All patients were bridged to liver transplantation successfully after median 20d (1-153d). The survival rate of ALSS plus LT patients is significantly higher than those in control groups.6. The patients who received long-term (more than 6 months) lamivudine treatment, who have been detected M204I/V and L180M variants pre-OLT by HBV quasispecies detection, may have HBV recurrence sooner after operation. The HBV recurrence OLT patients have a complicated quasispecies than non- recurrence patients.7. The frequency of Pc18-27 antigen-specific CTL post-OLT in 10 HLA-A2 positive HBV non-recurrence OLT patients is remarkably lower than those of pre-OLT. The frequency of Pcl8-27 and Pel83-191 antigen-specific CTL have no difference between the 9 HBV recurrence OLT patients and chronic Hepatitis B patients while The frequency of Pe335-343 and Tp575-583 antigen-specific CTL of the former are much lower than those of the latter. The proportion of Pc18-27 antigen-specific CTL which can secrete IFN also has no difference between HBV recurrence OLT patients and chronic Hepatitis B patients. The Pc18-27 antigen-specific CTL was found have a highest frequency among the 4 antigen-peptide -specific CTL.Conclusion:1. OLT is an effective treatment for the HBV correlated end-stage liver disease. It is important for us to choice the optimal operation opportunity. 2. The HBV recurrence rate of HBV DNA negative pre-OLT patients is 6.8%(6/88), so these patients should be treatment with nucleoside analogues on the schedule of waiting list immediately before OLT.3. Long-term nucleoside analogues treatment pre-OLT(>6 months), the occurrence of resistant HBV pre-OLT may result in the HBV recurrence post-OLT.4. The complexity of HBV quasispecies pre-OLT has correlative with HBV recurrence. The more complicated the HBV quasispecies is, the more high the HBV recurrence rate is.5. ALSS treatment can not only improve effectively the condition of patients before operation and provide supportive effect as a bridge to liver transplantation, but also degrade the HBV DNA level.6. HBV specificCTL response can be reconstruction after HBV recurrence post-OLT, but the whole cell immunity action is too weak and the specific CTL response is ununiformity among the different HBV peptide, so it cann't clear the HBV easily after HBV recurrence post-OLT.