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- Patients and Methods
Hepatitis B virus (HBV) recurrence after liver transplantation is significantly reduced by prophylaxis with hepatitis B immune globulins (HBIG) or antiviral drugs in nonreplicating patients and by the combination of both drugs in replicating patients. However, the load of HBV DNA, which defines replicating status in patients undergoing liver transplantation, remains unclear. This study analyzes the correlation between the viral load, tested with a single amplified assay, at the time of liver transplantation, and the risk of hepatitis B recurrence in 177 HBV carriers who underwent transplantation in a single center from 1990 to 2002. Overall, HBV relapsed after surgery in 15 patients (8.5%) with a 5- and 8-year actuarial rate of recurrence of 8% and 21%, respectively. After liver transplantation hepatitis B recurred in 9% of 98 selected subjects treated only with immune globulins and in 8% of 79 viremic patients who received immune globulins and lamivudine (P = NS). A linear correlation was observed between recurrence and viral load at the time of surgery. In transplant patients with HBV DNA higher than 100,000 copies/mL, 200–99,999 copies/mL, and DNA undetectable by amplified assay, hepatitis B recurred in 50%, 7.5%, and 0% of patients, respectively. Overall, a viral load higher than 100,000 copies/mL at the time of liver transplantation was significantly associated with hepatitis B recurrence (P = .0003). In conclusion, spontaneous or antiviral-induced HBV DNA viral load at the time of surgery classifies the risk of HBV recurrence after liver transplantation and indicates the best prophylaxis strategy. (Liver Transpl 2005;11:402–409.)
In the last 10 years clinical practice for liver transplantation (LT) in hepatitis B surface antigen (HBsAg)-carriers has been influenced by innovative treatment options. The introduction of high doses of hepatitis B immune globulins (HBIG) or of lamivudine (LAM) as post-LT mono-prophylaxis has reduced the risk of hepatitis B recurrence to a variable cumulative rate ranging between 10% and 50%. During prophylaxis with LAM or HBIG a strict correlation between hepatitis recurrence and hepatitis B virus (HBV) DNA load at the time of surgery has been found, which is related to the emergence of viral mutants that are unresponsive to therapy, such as surface antigen (HBsAg) mutants and tyrosine-methionine-aspartate-aspartate (YMDD)-mutants.1–5 Moreover, neither HBV recurrence nor graft failure have been observed in patients with HBV DNA undetectable by polymerase chain reaction at the time of surgery and treated with HBIG.6
The risk of hepatitis B recurrence can be reduced to less than 10% by using LAM before and after LT, in association with HBIG.7–13 Moreover, although LAM therapy before transplantation can improve liver function and decrease mortality,14 long-term antiviral therapy can select YMDD mutants whose management needs the use of alternative drugs, such as adefovir dipivoxil (ADV), to reduce HBV recurrence after LT.15–19
However, a variety of issues still remain controversial. In particular, doubts remain as to what virological status has to be achieved in patients undergoing LT and which HBV DNA assays have to be performed. This study analyzes 177 HBsAg carriers who underwent transplantation in a single center between 1990 and 2002 with the aim of evaluating the prognostic role of the HBV DNA viral load at the time of surgery on the risk of hepatitis B recurrence.
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- Patients and Methods
After liver transplantation, patients were followed up for a median time of 1,328 days (44 months), with a range of 63 to 3,906 days.
Eleven patients (6%) died after LT; in 4 of them (36%), death was related to HBV recurrence complicated by liver failure occurring between 10 and 40 months (median time 20 months) after LT.
Overall, hepatitis B relapsed in 8.5% of the HBsAg carriers who underwent transplantation (15 of 177), with a 5- and 8-year actuarial risk of 8% and 21%, respectively. Recurrence occurred in 9 (9%) of 98 patients receiving mono-prophylaxis therapy and in 6 (8%) of 79 patients of the combined prophylaxis group after surgery (P = NS) (Table 2 and Fig. 1). In the combined group none of the subjects who experienced the hepatitis B recurrence had evidence of LAM-resistant HBV mutants and HBV DNA breakthrough at the time of transplantation or needed adefovir therapy for YMDD mutants before surgery.
Table 2. Antiviral Therapy Before Surgery and Clinical Outcome After Liver Transplantation in Different Infectious Groups
| ||Median HBV DNA at time of LT copies/mL||Number of Patients|
|HBV recurrence (%)||300,000||12 (12)||0||3 (27)||0||15 (8.5)|
|HBV recurrence free||230||86||62||8||6||162|
|Mono-prophylaxis group (% HBV recurrence)||253||36 (17)||48 (0)||9 (33)||5 (0)||98 (9)|
|Combined prophylaxis group (% HBV recurrence)||360||62 (9.6)||14 (0)||2 (0)||1 (0)||79 (8)|
Figure 1. Actuarial risk of hepatitis B recurrence after LT in 98 patients treated only with HBIG after surgery (mono-prophylaxis group) and in 79 subjects treated with LAM and immune globulins (combined prophylaxis group).
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The retrospective quantitative analysis of HBV DNA levels by PCR assay showed an overall median viremia at the time of LT of 300 copies/mL (mean 227,293 copies/mL), ranging from an undetectable value to 16,500,000 copies/mL. The HBV DNA median value was 253 copies/mL (mean 378,496 copies/mL; range 199–16,500,000 copies/mL; SD ± 1,834,505) in the 98 patients of the mono-prophylaxis group and 360 copies/mL (mean 39,724 copies/mL; range 199–1,900,000 copies/mL; SD ± 219,422) in the 79 subjects of the combined prophylaxis group (P = NS) (Table 2).
A linear correlation between the levels of HBV DNA at the time of LT and risk of HBV recurrence was observed, particularly in the mono-prophylaxis group (Fig. 2A-B).
Figure 2. Correlation between arbitrary groups of HBV DNA loads by PCR COBAS at the time of liver transplant and rate of HBV recurrence in monotherapy group (A) and in combined prophylaxis group (B).
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Patients with HBV recurrence had a median viral load of 300,000 copies/mL (mean 1,793,847 copies/mL; range 350–16,500,000 copies/mL; SD ± 4,186,246) vs. 230 copies/mL (mean 82,241 copies/mL range 199–6,000,000 copies/mL, SD ± 555,352) in subjects without HBV recurrence (P = 0.0002).
Patients with HBV DNA ≥ 100,000 copies/mL at moment of LT had a rate of HBV recurrence of 50% (9 of 18 patients), which is significantly higher than the rate of 4% found in the patients with lower HBV DNA levels (6 of 159 patients) (P = 0.0003) (Fig. 3). Post-LT hepatitis B recurred in 8 (53%) of the 15 highly viremic patients treated only with mono-prophylaxis after LT, and in one of the 3 subjects of this group treated with the combined therapy (in these patients LAM was used before LT for a median time of 56 days, ranging between 13 and 150 days).
Conversely, hepatitis B recurred in none of the 79 patients (34 in the mono- and 45 in the combined prophylaxis group) who underwent a transplantation with a spontaneous or antiviral-induced undetectable viral load at the time of surgery.
In patients with a positive viral load below 100,000 copies/mL the rate of HBV recurrence was 7.5%. In this subgroup HBV recurred in 5 patients in the combined group (treated with LAM for a mean of 185 days, range 80–270, before LT) and in only one subject treated with mono-prophylaxis (P = 0.008) (Table 3 and Fig. 4).
Figure 3. Risk of hepatitis B recurrence after LT in patients with HBV DNA load (COBAS PCR) higher or lower than 100,000 copies/mL at the time of surgery.
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Table 3. HBV Recurrence After LT in 177 Patients Analyzed in the Basis of the Viral Load (COBAS) at the Time of Surgery, Post-Liver Transplantation Prophylaxis (Combined or Mono-prophylaxis) and Viral Co-infections
| ||HBV DNA at LT copies/mL|
|HBV|| || || || || || || || |
| Total pts||23||15||36||12||3||9||62||36|
| N. rec (%)||0||0||5 (14)||1 (8)||1 (33)||5 (55)||6 (10)||6 (17)|
|HDV|| || || || || || || || |
| Total pts||10||24||4||23||0||1||14||48|
| N. rec (%)||0||0||0||0||—||0||0||0|
|HDC|| || || || || || || || |
| Total pts||0||4||1||1||0||0||1||5|
| N. rec (%)||—||0||0||0||—||—||0||0|
|HBC|| || || || || || || || |
| Total pts||1||2||1||2||0||5||2||9|
| N. rec (%)||0||0||0||0||—||3 (60)||0||3 (33)|
|Total|| || || || || || || || |
| Total pts||34||45||42||38||3||15||79||98|
| N. rec (%)||0||0||5 (12)||1 (3)||1 (33)||8 (53)||6 (8)||9 (9)|
Figure 4. Actuarial risk of hepatitis B recurrence free after LT in patients with HBV DNA < 100,000 copies/mL (COBAS PCR) at the time of surgery, treated only with immune globulins (mono-prophylaxis group, Mono) or with immune globulins and LAM (combined prophylaxis group, Comb) after surgery.
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Among the variables analyzed, only four (type of viral infection, HBeAg status, anti-HBe status, and HBV DNA load at the time of LT) correlated with the rate of post-LT HBV recurrence in the univariate analysis (P < 0.05 for all variables). In the multivariate analysis obtained using a stop-wise Cox regression model only the HBV DNA load by COBAS at the time of surgery was significantly associated with post-LT hepatitis B recurrence, which shows that it has an independent predictive value in this setting (P = 0.001, hazard ratio 5.93; 95% CI 2.01–17.52).
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- Patients and Methods
This study analyzes the risk of HBV recurrence after LT in 177 HBsAg carriers who underwent transplantation in a single Italian center. Overall, the HBV recurrence rate was low (8.5%), confirming that with correct selection the HBsAg carrier condition had become one of the best indications to LT in the late 1990s.
In this study the rate of HBV recurrence was strongly influenced by the Center's criteria during the 12-year period. Only 33 HBsAg carriers underwent transplantation before 1996, when eligibility for LT was considered negativity of HBV DNA, and 144 underwent transplantation after 1996, when combined therapy with LAM and immune globulins became available. The new treatment strategies significantly increased the number of transplantable HBsAg carriers and the number of transplants for HBV, while it decreased the actuarial rate of recurrence from 21% to 8% in the last 5 years of analysis.
In the study no difference in HBV recurrence rate was observed between patients treated with the mono- or combined prophylaxis, probably due to comparable viremic loads detectable in both groups at the time of surgery (median HBV DNA 253 vs. 360 copies/mL, respectively). The virologic features of the patients, reported in Tables 1 and 2, influenced the results of the study. Spontaneously low or nonreplicating patients (prevalently HDV-coinfected) were treated with immune globulins, while spontaneous replicating cases (with prevalently HBV-related cirrhosis) were treated with the combined prophylaxis, to achieve a low viremia before LT and to control escape-mutants after surgery. Consequently, we observed a lower than expected hepatitis B recurrence rate in the mono-therapy group and a higher one in the combined group.
Moreover, results were influenced by the HBIG protocol used in our Center, a medium-dose schedule in relation to the published data on HBIG prophylaxis2 and a high-dose protocol if referred to recent studies on combined prophylaxis.10–12 Consequently, the data of the study are not necessarily comparable to those reported by other centers using high-dose HBIG schedules in mono-therapy for replicating patients or low-dose HBIG protocols in combination with LAM. Despite the limitations of a retrospective analysis, a linear correlation between the spontaneous or antiviral-induced viral load at the time of LT and the risk of HBV recurrence was found. In particular, in patients receiving only HBIG after LT, a significantly lower risk of HBV recurrence was seen in those with low levels of viremia compared with those with higher loads at moment of surgery. This difference was not significant in the combined prophylaxis group, probably due to the low number of patients (only 3 patients) with HBV DNA higher then 100,000 copies/mL at transplantation (Fig. 2B).
In correlation to the HBV DNA load at the time of LT, three categories of HBV recurrence risk were identified: patients with undetectable HBV DNA by PCR and patients with HBV DNA lower or higher than 100,000 copies/mL. Patients with high levels of HBV DNA (≥100,000 copies/mL) at the time of LT maintained a high risk (33%–53%) of recurrence during both mono- or combined prophylaxis, although the small number of patients in the latter group and a single recurrence do not permit conclusions on the combined prophylaxis strategy in subjects with a high viral load at the time of surgery.
None of the 79 patients with negative HBV DNA by PCR at the time of surgery experienced hepatitis B recurrence, as reported in a previous study.6 This group included both patients treated with antivirals such as LAM or adefovir, and spontaneous nonreplicating patients.21 In this virological setting immune globulins were safely used as mono-prophylaxis in spontaneus nonreplicating patients and in association with antivirals (combined prophylaxis) in replicating patients. These data permit us to speculate that in spontaneous nonreplicating patients, mono-therapy with immune globulins could be safely shifted into mono-therapy with LAM, as recently proposed by other authors.22, 23 Moreover, LAM therapy before surgery could be appropriate in all patients in order to obtain the complete negativization of HBV DNA so as to minimize the risk of hepatitis B recurrence.
Transplantation with a detectable viral load below 100,000 copies/mL corresponded with a lower (7.5%), but not null, residual risk of hepatitis recurrence. Specifically, patients with a spontaneous viral load of with a similar load while on LAM therapy maintained a significant risk of post-LT relapse (P = 0.008, Fig. 4). Our data allow us to speculate that in patients with a spontaneous high viral fitness the persistence of a viral load while on LAM therapy could result in the proliferation of escape-mutants/drug-resistant strains to combined prophylaxis after surgery. Consequently in these subjects the shift to LAM as mono-therapy should be tested carefully and under strict virological monitoring. In any case, only patients whose results are negative for YMDD mutants, without evidence of HBV persistence post-LT24 should be candidates for LAM mono-therapy, perhaps even in association with effective vaccination schedules after a peri-operative HBIG prophylaxis.25, 26
In the multivariate analysis the only variable significantly associated with post-LT hepatitis B recurrence was the viral load at the time of surgery; the level able to identify the significant replicating status in HBsAg carriers undergoing liver transplantation was 100,000 copies/mL by PCR. A higher or lower load at the time of LT was associated with a hepatitis recurrence of 50% and 4%, respectively (P = 0.0003). This level could represent the HBV DNA value to reach through antiviral pre-emptive therapy before LT in active replicating patients in order to significantly reduce their risk of hepatitis B recurrence.
In summary, this study indicates that the HBV DNA load at the moment of LT, as detected by an amplified sensitive assay, can quantify the risk of HBV recurrence after surgery and can suggest which prophylactic strategy is needed. A viral load of 100,000 copies, in analogy with the cutoff limit of 105 copies/mL proposed in the antiviral therapy of HBV immunocompetent patients,27–29 identifies the load of significant replication in HBsAg carrier candidates to LT. In our opinion this is the minimum value achievable to define the patient as suitable for transplant with an acceptable (<10%) risk of hepatitis B recurrence. The goal of a complete inhibition of replication, albeit desirable for the full protective effect, has to be assessed against the risk connected with a prolongation of the waiting time before LT and to the emergence of LAM-resistant mutants.