Impact of hemodialysis therapy on hepatitis C virus infection: a deeper insight

Hepatitis C Virus (HCV) infection remains prevalent in patients receiving regular dialysis all over the world. The adverse impact of anti-HCV serologic status on mortality in the dialysis population has been documented. Antiviral therapy for hepatitis C in chronic kidney disease (CKD) patients, including the dialysis population, is still unsatisfactory. Several findings support a different course of HCV in dialysis patients versus the non-uremic population. The HCV viral load appears lower in hemodialysis patients with HCV despite the immune compromise caused by chronic uremia; the histologic abnormalities seem milder, and a severe clinical course of chronic hepatitis C is unusual in most hemodialysis (HD) patients. It appears that the HD procedure per se can preserve patients from an aggressive course of HCV by reducing the viral load (HCV RNA). The mechanisms by which the HD procedure lowers HCV viremia remain largely speculative: the passage of viral particles into the dialysate, the trapping of the virus on the surface of the dialyzer membrane, and an indirect host-mediated mechanism have been cited. The latter hypothesis implicates the production of interferon-alpha, hepatocyte growth factor, or other cytokines provided with antiviral activities during the hemodialysis sessions. Clinical trials aimed at clarifying this issue are under way.

Kinetics of hepatitis B virus load and haemodialysis: a prospective study

The control of the spread of hepatitis B virus (HBV) infection within dialysis units has been an important goal in the management of patients on regular dialysis but infected patients continue to enter the dialysis system. It is evident that HBV viraemia in hepatitis B surface antigen (HBsAg)-positive patients on dialysis is low but it remains unclear whether haemodialysis per se can contribute to viral load reduction in such patients. HBV DNA was determined in 40 HBsAg-positive patients on maintenance haemodialysis immediately before and at the end of a 4-h haemodialysis session. The same measurements were repeated 48 and 72 h later. Twenty (50%) of 40 HBsAg-positive patients had detectable HBV DNA in serum. Detectable HBV DNA in serum was not predicted by demographic, clinical or biochemical parameters. HBV load decreased in the majority of patients after haemodialysis, although the difference was not significant (29 390 +/- 48 820 vs 23 862.8 +/- 4 350 copies/mL, NS). There was a strong relationship between mean HBV DNA levels before dialysis and absolute reduction of HBV DNA during haemodialysis sessions (r = 0.75, P = 0.0001). No difference occurred in the magnitude of change in HBV DNA titre when comparing cellulosic to synthetic membranes. Haemodialysis per se leads to a reduction in HBV load in HBsAg-chronic carriers on maintenance dialysis. This phenomenon could explain the low viral loads in these patients. Prospective studies are in progress to identify the mechanisms responsible for reduction in HBV load during haemodialysis.

Treatment of dialysis patients with chronic hepatitis C using pegylated interferon and low-dose ribavirin

BACKGROUND

No safe and effective therapy exists for chronic hepatitis C in dialysis patients. Available data on the antiviral treatment of hepatitis C in dialysis population is mostly based on standard interferon monotherapy.

OBJECTIVES

We conducted a prospective, cohort trial with combined therapy (pegylated-interferonalpha-2a (135 mcg/week) plus low dose ribavirin (200 mg/day)) for chronic hepatitis C in 15 patients undergoing long-term dialysis. Twelve patients had HCV genotype 1a/1b, three were co-infected with human immunodeficiency virus (HIV), and two had compensated cirrhosis. End-points were sustained viral response and adverse effects.

RESULTS

Sustained virological response was obtained in four patients (including two with HCV genotype 1); the SVR rate was 28.6% (4/14), on an intention-to-treat analysis. One subject with SVR had compensated cirrhosis. All HIV co-infected patients had well controlled HIV and one of them (33%) reached SVR. Seven (50%) of the 14 patients were non-responders, two of which relapsed after discontinuation of therapy. Drop-out rate was 71.4% (10/14). The most frequent side-effect was anemia, which required ribavirin discontinuation in three patients; seven (47%) patients received blood transfusions. Two patients died (week 4 and 14) of causes related to cardiovascular disease, which was frequent in our cohort. Two subjects were hospitalized and discontinued therapy (week 1, and 27).

CONCLUSIONS

Results from this study showed that about one-third of HD patients achieved sustained virological response with pegylated-interferon-alpha-2a plus low-dose ribavirin; however, tolerance to antiviral treatment was unsatisfactory. Well- controlled HIV infection should not be a contraindication to HCV therapy in dialysis patients. Prospective, controlled clinical trials of combined antiviral therapy targeted at HCV in chronic kidney disease population are indicated.

Antiviral therapy of hepatitis C in chronic kidney diseases: meta-analysis of controlled clinical trials

Hepatitis C virus (HCV) infection remains frequent in patients with chronic kidney disease and the detrimental role of HCV on survival is well-established in this population. Several authors have reported on efficacy and safety of antiviral therapy for hepatitis C in this polulation but there is no clear consensus on management. To evaluate efficacy and safety of antiviral therapy for hepatitis C in patients with chronic kidney disease, we performed a systematic review of the published medical literature and completed a meta-analysis of controlled clinical trials. The primary outcome was sustained virological response (as a measure of efficacy); the secondary outcome was drop-out rate (as a measure of tolerability). We used the random effects model of Der Simonian and Laird, with heterogeneity and sensitivity analyses. We identified 13 studies including 539 unique patients; 10 (76.9%) concerned patients on maintenance dialysis. Only prospective, controlled clinical trials were included. Pooling of study results showed a significant increase of viral response in study (patients treated with antiviral therapy) than control patients (patients who did not receive therapy), the pooled odds ratio (OR) of failure to obtain a sustained viral response was 0.081 [95% confidence intervals (CI), 0.029-0.230], P = 0.0001. The pooled OR of drop-out rate was significantly increased in study vs control patients, OR = 0.389 (95% CI, 0.155-0.957), P = 0.04. The studies were heterogeneous with regard to viral response and drop-out rate. In the subset of clinical trials (n = 6) involving only dialysis patients receiving interferon (IFN) monotherapy for chronic HCV, there was a significant difference in the risk of failure to obtain a sustained viral response (study vs control patients), OR = 0.054 (95% CI, 0.019; 0.150), P = 0.0001 (random-effects model). No significant (NS) heterogeneity was found (Q = 14.604, P = 1.0). No difference in the drop-out rate between study and control patients was shown, OR = 0.920 (95% CI, 0.367; 2.311), NS. This result being homogeneous (Q = 3.639, P = 0.388). Our meta-analysis showed that the viral response was greater in patients with chronic kidney disease who received antiviral therapy than controls. No difference in the drop-out rate between study and control patients occurred in the subgroup of dialysis patients on IFN monotherapy. These results support IFN-based therapy for hepatitis C in patients on maintenance dialysis.

Hepatitis C infection in patients with chronic kidney disease

The management of hepatitis C virus (HCV)-infected patients with chronic kidney disease (CKD) is complex and represents a particular concern since numerous issues, such as antiviral therapy in dialysis patients and post renal transplant, and prevention of HCV spread within dialysis units, remain unresolved. An enormous body of literature has been published on HCV in the CKD population; however, clinical evidence on important issues is mostly based on uncontrolled clinical trials or retrospective surveys. The aim of this paper is to provide a systematic review of the literature. Responses to the critical issues have been developed by a consensus of experts, endorsed by the Italian Association for the Study of the Liver (AISF) and some clinical recommendations have been added.

Interferon monotherapy of chronic hepatitis C in dialysis patients: meta-analysis of clinical trials

The efficacy of monotherapy with interferon (IFN) (conventional or pegylated IFN) in dialysis patients with chronic hepatitis C remains unclear, although a number of clinical trials have been published addressing this issue. The aim of the study was to evaluate the efficacy and safety of monotherapy by conventional or pegylated IFN in dialysis patients with chronic hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical trials. The primary outcome was sustained virological response (SVR; as a measure of efficacy), and the secondary outcome was drop-out rate (as a measure of tolerability). We used the random-effects model of Der Simonian and Laird, with heterogeneity and sensitivity analyses. We identified 28 clinical trials (645 unique patients), of which six (21.4%) had a controlled design. In the group of trials based on conventional IFN, the summary estimate for SVR and drop-out rate was 39% [95% confidence interval (CI) 32-46] and 19% (95% CI 13-26) respectively. The summary estimate for SVR rate in patients with the hepatitis C virus genotype 1 was 33% (95% CI 19-47). In the subset of trials using pegylated IFN, the summary estimate for SVR and drop-out rate was 31% (95% CI 7-55) and 27% (95% CI 1-52) respectively. The most frequent side-effects requiring interruption of treatment were flu-like symptoms, and gastrointestinal and haematological changes. A relationship between age and drop-out rate was found, even if no statistical significance was reached (P = 0.064). The studies were heterogeneous with regard to SVR and drop-out rate. No publication bias was observed. One-third of dialysis patients with chronic hepatitis C were successfully treated with conventional or pegylated IFN monotherapy. Preliminary evidence does not support additional benefit due to monotherapy with pegylated IFN on the viral response in the chronic kidney disease (CKD) population. Tolerance to IFN monotherapy was unsatisfactory, particularly to pegylated IFN. The optimal antiviral treatment of chronic hepatitis C in dialysis populations is currently under active investigation.

Hepatitis C virus infection and rituximab therapy after renal transplantation

BACKGROUND

Rituximab, a chimeric monoclonal antibody, has been successfully given in various diseases including HCV-associated mixed cryoglobulinemia. However, only preliminary data exists on its efficacy and safety after renal transplantation.

METHODS

We report on a renal transplant recipient with chronic hepatitis C who received rituximab therapy for gastric cancer. Four rituximab infusions of 375 mg/m(2) were given.

RESULTS

Rituximab therapy was complicated by cholestatic hepatitis C with very high HCV RNA levels; liver insufficiency occurred. The patient developed bacterial pneumoniae and respiratory insufficiency was the cause of death. Although other mechanisms cannot be excluded, we found that rituximab therapy was implicated in the pathogenesis of cholestatic hepatitis C in our patient.

CONCLUSIONS

We suggest that rituximab therapy may be associated with significant side effects. More experience has to be accumulated before any conclusions on efficacy and safety of rituximab therapy after RT can be drawn.

The impact of hepatitis C virus infection on survival in dialysis patients: meta-analysis of observational studies

The impact of hepatitis C virus (HCV) infection on mortality of patients receiving regular dialysis remains unclear. The assessment of the natural history of HCV in dialysis population is difficult because of the low progression of HCV-related liver disease over time and the reduced life expectancy in patients with end-stage renal disease. The aim of the study was to conduct a systematic review of the published medical literature concerning the impact of HCV infection on the survival of patients undergoing maintenance dialysis. The relative risk of mortality was regarded as the most reliable outcome end-point. Study-specific relative risks were weighted by the inverse of their variance to obtain fixed- and random-effects pooled estimates for mortality with HCV across the published studies. We identified seven studies involving 11 589 unique patients on maintenance dialysis; two (29%) were case-control studies. Pooling of study results demonstrated that presence of anti-HCV antibody was an independent and significant risk factor for death in patients on maintenance dialysis. The summary estimate for adjusted relative risk (aRR) (all-cause mortality) was 1.34 with a 95% confidence interval (CI) of 1.13-1.59. Heterogeneity statistics, R(i) = 0.48 (P-value by Q-test = 0.13). In a sensitivity analysis including only (n = 5) cohort studies, the pooled aRR was 1.38 (95% CI, 1.20-1.59); heterogeneity statistics R(i) = 0.46. As a cause of death, hepatocellular carcinoma and liver cirrhosis were significantly more frequent among anti-HCV-positive than -negative dialysis patients. Our meta-analysis indicates that anti-HCV-positive patients on dialysis have an increased risk of mortality compared with HCV-negative patients. The excess risk of death in HCV-positive patients may be at least partially attributed to chronic liver disease with its attendant complications.

Prophylaxis and treatment of hepatitis B in immunocompromised patients

The literature on hepatitis B virus (HBV) in immunocompromised patients is heterogeneous and referred mainly to the pre-antivirals era. Today a rational approach to the problem of hepatitis B in these patients provides for: (a) the evaluation of HBV markers and of liver condition in all subjects starting immunosuppressive therapies (baseline), (b) the treatment with antivirals (therapy) of active carriers, (c) the pre-emptive use of antivirals (prophylaxis) in inactive carriers, especially if they are undergoing immunosuppressive therapies judged to be at high risk, (d) the biochemical and hepatitis B surface antigen (HBsAg) monitoring (or universal prophylaxis, in case of high risk immunosuppression) in subjects with markers of previous contact with HBV (HBsAg negative and anti-HBc positive), in order to prevent reverse seroconversion. Moreover it is suggested a strict adherence to criteria of allocation based on the virological characteristics of both recipients and donors in the general setting of transplants and in liver transplantation the universal prophylaxis with nucleos(t)ides analogues (frequently combined with specific anti-HBV immunoglobulins) in HBsAg positive candidates and in HBsAg negative recipients of anti-HBc positive grafts.

Gamma glutamyltranspeptidase activity and viral hepatitis in dialysis population

BACKGROUND

Numerous investigations have reported that viral hepatitis is associated with significant hepatocellular damage, as expressed by raised aminotransferases in serum, in dialysis population. However, scarce information exists on the activity of gamma glutamyltranspeptidase (GGTP) in dialysis patients with infection by hepatotropic viruses.

OBJECTIVES

We measured serum GGTP values in a large cohort (n=757) of patients receiving long-term dialysis; healthy controls were also included. The relationship between GGTP values and a series of demographic, clinical, and biochemical parameters was analyzed.

METHODS

Serum GGTP levels were tested by spectrophotometry. A subset (n=333) of dialysis patients was tested by molecular technology (branched-chain DNA (bDNA) assay) to evaluate the relationship between serum GGTP and HCV viremia. A subgroup (n=78) of dialysis patients was analyzed by an ultrasound scan of gallbladder and biliary tract to assess the presence of gallstone disease. Multivariate analyses were made using regression models; serum GGTP values were included as a dependent variable. The usefulness of serum GGTP levels in detecting HBsAg and anti-HCV positivity was evaluated using receiver operating characteristics (ROC) curve analysis.

RESULTS

Univariate analysis showed that serum GGTP levels were significantly higher in HBsAg positive and/or anti-HCV positive patients than in HBsAg negative/anti-HCV negative patients on dialysis; 85.1+/-184.1 versus 25.86+/-23.9 IU/l (P=0.0001). The frequency of raised GGTP levels was 22.2% (41/184) among dialysis patients with chronic viral hepatitis. Multivariate analysis showed a significant and independent association between serum GGTP values and positive HBsAg (P=0.005) and anti-HCV antibody (P=0.0001) status. Mean GGTP values were significantly higher in study patients than controls, 32.32+/-60.02 versus 23.5+/-16.92 IU/L (P=0.01); however, no significant difference with regard to GGTP between study and healthy cohorts persisted after correction for age, gender, race, and viral markers. No relationship between gallstone disease and serum GGTP was found (NS). An independent and significant association (P=0.0291) between raised GGTP levels and detectable HCV RNA in serum was noted among patients tested by biology molecular techniques. ROC technology demonstrated that GGTP was equally useful for detecting HBV (P=0.0004) and HCV (P=0.0005) among dialysis patients.

CONCLUSIONS

We found an independent and significant association between serum GGTP values and HBsAg and/or anti-HCV antibody in dialysis population. Twenty-two percent of dialysis patients with chronic viral hepatitis had elevated GGTP. No difference in GGTP between HBsAg- negative/anti-HCV- negative dialysis patients and healthy individuals was found. Routine testing for serum GGTP levels to assess liver disease induced by hepatotropic viruses or other agents in dialysis population is suggested.

Meta-analysis: anti-viral therapy of hepatitis C virus-related liver disease in renal transplant patients

BACKGROUND

The efficacy and safety of interferon-based therapy in renal transplant recipients with hepatitis C remains unclear, although a number of small clinical trials have been published addressing this issue.

AIM

To evaluate efficacy and safety of antiviral therapy with interferon (interferon alone or interferon plus ribavirin) in renal transplant patients with hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical trials.

METHODS

The primary outcomes were sustained virological response (as a measure of efficacy) and/or drop-out rate (as a measure of tolerability). We used the random-effects model of DerSimonian and Laird, with heterogeneity and sensitivity analysis.

RESULTS

We identified 12 clinical trials (102 unique patients); there was one controlled study. The summary estimate for sustained virological response and drop-out rate was 18.0% (95% CI 7.0-29.0%) and 35.0% (95% CI 20-50%), respectively. The most frequent side-effect requiring interruption of treatment was graft dysfunction (n = 28; 71.7%). Meta-regression analysis showed an inverse and significant association between reference year and drop-out logit rate (P = 0.012); an inverse link between sustained virological response logit rate and frequency of hepatitis C virus genotype 1 (P = 0.067) and cirrhosis (P = 0.08) was found, even if no statistical significance was reached. No publication bias was observed.

CONCLUSIONS

Interferon-based therapy of hepatitis C has poor tolerance and safety after renal transplant. The optimal treatment of hepatitis C after renal transplant requires additional agents or alternative therapeutic approaches.

Meta-analysis: terlipressin therapy for the hepatorenal syndrome

BACKGROUND

The hepatorenal syndrome is a severe and well-known complication of end-stage liver disease, but its management is controversial. Recent reports have shown the efficacy of terlipressin therapy, a vasopressin analogue, in hepatorenal syndrome patients.

AIM

To evaluate the efficacy and safety of terlipressin in the treatment of hepatorenal syndrome.

METHODS

We performed a systematic review of the literature with a meta-analysis of clinical trials. The primary outcome (as a measure of efficacy) was the rate of responder patients (i.e. patients who had hepatorenal syndrome reversal after terlipressin therapy). The secondary outcomes were the rate of responders who had hepatorenal syndrome recurrence after terlipressin withdrawal, and the drop-out rate (as a measure of tolerability). We used the random effects model of DerSimonian and Laird with heterogeneity and sensitivity analysis.

RESULTS

We identified 10 clinical trials (154 unique patients); two (20.0%) were randomized, controlled trials. The pooled rate of patients who reversed hepatorenal syndrome after terlipressin therapy was 0.52 (95% CI, 0.42; 0.61), P = 0.0001; I2 = 24.6%. The pooled frequency of responder patients who showed hepatorenal syndrome recurrence after terlipressin withdrawal was 0.55 (95% CI, 0.40; 0.69), P = 0.00001; I2 = 44.3%. The pooled rate of patients who showed side-effects to terlipressin therapy was 0.29 (95% CI, 0.17; 0.42), P < 0.0001, I2 = 66.6%. The drop-out rate was 0%. The pooled OR for mortality rate in hepatorenal syndrome patients who were not responders to terlipressin vs. responder patients was 5.746 (95% CI, 1.5; 21.9). We did not find any predictive factor of response to terlipressin therapy.

CONCLUSIONS

This meta-analysis shows efficacy and safety of terlipressin in the treatment of hepatorenal syndrome. However, a significant number of responder patients relapsed after terlipressin withdrawal. Further studies are in progress to address the link between terlipressin and survival in hepatorenal syndrome patients.

Meta-analysis: the adjuvant role of granulocyte macrophage-colony stimulating factor on immunological response to hepatitis B virus vaccine in end-stage renal disease

BACKGROUND

Chronic dialysis patients often fail to produce protective antibodies to hepatitis B virus surface antigen after vaccination towards hepatitis B virus (HBV). Several authors suggested a benefit for granulocyte macrophage-colony stimulating factor (GM-CSF) as an adjuvant to HBV vaccination in patients with end-stage renal disease (ESRD). However, consistent information is still lacking.

AIMS

To evaluate efficacy and safety of GM-CSF as adjuvant to hepatitis B vaccine in patients with ESRD by performing a systematic review with a meta-analysis of prospective controlled clinical trials (CCTs).

METHODS

Only trials comparing the seroresponse rate in study (GM-CSF plus HBV vaccine) versus control (HBV vaccine alone) patients were included. We used the random effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses. The end-point of interest was the rate of patients showing seroprotective anti-hepatitis B titers at completion of HBV vaccine schedule in study versus control groups.

RESULTS

We identified seven studies involving 187 unique patients with ESRD. Only prospective CCTs were included. Pooling of study results showed a significant increase in response rates among study (GM-CSF plus HBV vaccine) versus control (HBV vaccine alone) patients (pooled Odds Ratio, 4.63 [95% Confidence Intervals, 1.42; 15.14]). The P-value was 0.02 for our test of study heterogeneity.

CONCLUSIONS

Our meta-analysis showed improved seroprotection rates with HBV vaccine after GM-CSF administration.

Meta-analysis: anti-viral therapy of hepatitis B virus-associated glomerulonephritis

BACKGROUND

Hepatitis B virus-associated glomerulonephritis is an infrequent complication of chronic hepatitis B virus (HBV) with significant morbidity. A causal association between hepatitis B virus infection and the development of glomerulonephritis remains controversial. Also, the optimal therapy is undefined although several approaches have been made.

AIM

To evaluate the efficacy and safety of anti-viral therapy (interferon or lamivudine) in HBV-associated glomerulonephritis by a systematic review and meta-analysis of clinical trials.

METHODS

The primary outcome was clinical response (as a measure of efficacy); the secondary outcomes were drop-out rate (as a measure of tolerability), and virological response. We used the random effects model of DerSimonian and Laird, with heterogeneity, sensitivity and meta-regression analyses.

RESULTS

We identified six clinical trials (84 unique patients); three had controlled design. The overall estimate for proteinuria remission was 65.2% (95% confidence intervals: 52.7-75.9%), Q-test for heterogeneity = 7.731, P = 0.172, I(2) = 35.327. The overall estimate for hepatitis B e antigen clearance was 62.0% (95% confidence intervals: 50.5-72.2%). The overall estimate for drop-out rate was 12.7% (95% confidence intervals: 6.4-23.6%). Meta-regression analysis showed a significant link between hepatitis B e antigen clearance and logit rate of proteinuria remission after interferon therapy [coefficient -2.585 (S.E. 1.089), P = 0.017].

CONCLUSION

Remission of the nephrotic syndrome is accompanied by clearance of HBV replication, supporting the role of the virus in the pathogenesis of the disease.

A topical nitric oxide-releasing dexamethasone derivative: effects on intraocular pressure and ocular haemodynamics in a rabbit glaucoma model

BACKGROUND

Topical nitric oxide-releasing dexamethasone (NCX1021) may avoid the negative effects of dexamethasone phosphate.

AIMS

To obtain more information on the role of nitric oxide in glaucoma and to compare a nitric oxide-releasing dexamethasone with dexamethasone phosphate with regard to intraocular pressure (IOP) and ocular haemodynamics in an experimental rabbit model.

METHODS

Six rabbits were treated with dexamethasone phosphate 0.1% in the right eye and with NCX1021 in the left eye for 5 weeks. The parameters considered were IOP, nitric oxide marker levels in aqueous humour, ocular haemodynamics of ophthalmic artery (by means of colour Doppler imaging), expression of endothelial nitric oxide synthase (eNOS)in ciliary processes and histology of ciliary bodies.

RESULTS

Dexamethasone increased IOP levels, NCX1021 did not. Nitrite and cyclic guanosine monophosphate levels in aqueous humour were lowered by dexamethasone and increased by NCX1021. Resistivity index of the ophthalmic artery was increased, eNOS expression was reduced and ciliary bodies showed histological lesions in dexamethasone-treated eyes, not in NCX1021-treated ones.

CONCLUSIONS

NCX1021 may avoid the IOP increase, impairment of ocular blood flow and the morphological changes in the ciliary bodies possibly induced by corticosteroid treatment.

Meta-analysis: intradermal vs. intramuscular vaccination against hepatitis B virus in patients with chronic kidney disease

BACKGROUND

Dialysis patients have suboptimal response towards hepatitis B virus (HBV) vaccine and intradermal hepatitis B virus vaccination has been used to improve the response rate; however, its efficacy remains unclear.

DESIGN

Meta-analysis of controlled trials comparing intradermal vs. intramuscular vaccine against HBV among chronic kidney disease patients.

IDENTIFICATION

Twelve studies involving 640 unique patients were included if they had controlled design, intervention and control group patients received intradermal or intramuscular vaccine against HBV, respectively. Patients were followed for a minimum of 7 months after the first vaccine dose.

MAIN OUTCOME MEASURES

The odds ratio of failure to respond to HBV vaccine among patients who received vaccine by intradermal vs. intramuscular route was the end point of interest. It was calculated at completion of HBV vaccination and over follow-up.

RESULTS

Pooling of study results demonstrated a decreased risk of failure to respond to HBV vaccine among patients who were vaccinated by intradermal vs. intramuscular route (pooled odds ratio at completion of vaccine protocol: 0.36; 95% CI: 0.21-0.62; test of study heterogeneity, P = 0.089). This difference did not occur over follow-up (6-60 months after completing vaccine schedule; pooled odds ratio: 1.1; 95% CI: 0.47-2.5).

CONCLUSIONS

Dialysis patients show higher seroprotection after intradermal than intramuscular vaccination schedules; this was not apparent over follow-up. Further studies are warranted to assess if the higher seroprotection rates obtained by intradermal route translates into reduced incidence of de novo HBV virus among chronic kidney disease patients.

Meta-analysis: the adjuvant role of thymopentin on immunological response to hepatitis B virus vaccine in end-stage renal disease

BACKGROUND

It has been calculated that 30-40% of dialysis patients fail to produce antibodies to HBsAg antigen after vaccination towards hepatitis B virus. Several authors have reported on the benefit of thymopentin (TP5) as adjuvant to vaccine against hepatitis B virus in patients receiving regular dialysis. However, consistent information on this issue is still lacking.

AIMS

To evaluate efficacy and safety of thymopentin as adjuvant to hepatitis B vaccine in dialysis patients by performing a systematic review with a meta-analysis of clinical trials.

METHODS

We used the random effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses.

RESULTS

We identified 11 studies involving 272 unique patients with end-stage renal disease. Only prospective, controlled trials were included. Pooling of study results did not show a significant increase in seroresponse rate among study (thymopentin plus hepatitis B virus vaccine) vs. control (hepatitis B virus vaccine alone) patients; the pooled odds ratio of failure to respond to hepatitis B virus vaccine was 0.677 (95% confidence intervals: 0.285-1.605); no heterogeneity was found (P = 0.0001). Thymopentin significantly improved the seroresponse rate in the subgroup of trials based on greater thymopentin doses (OR: 0.184; 95% CI: 0.085-0.398).

CONCLUSIONS

Our meta-analysis showed that thymopentin significantly improved the seroresponse rate towards hepatitis B vaccine only in dialysis patients treated with higher thymopentin doses. The limited number of patients precluded definitive conclusions.

Meta-analysis: the dialysis mode and immunological response to hepatitis B virus vaccine in dialysis population

BACKGROUND

Patients on maintenance dialysis typically show a suboptimal immune response to hepatitis B virus vaccine compared with the non-uraemic population. Some authors have claimed that dialysis mode has an impact on the immune response to hepatitis B virus vaccine but consistent information is lacking on this issue.

AIM

To evaluate the relationship between dialysis mode and immune response to hepatitis B vaccine in dialysis population by performing a systematic review with a meta-analysis of clinical trials.

METHOD

We used the random effects model of DerSimonian and Laird; sources of heterogeneity in effect estimates were explored by performing sensitivity analyses.

RESULTS

The relative risk of failure to respond to hepatitis B vaccine among patients who underwent maintenance haemodialysis vs. peritoneal dialysis was the end point of interest. We identified 14 clinical trials involving 1211 unique patients on maintenance dialysis. Pooling of study results did not show a significant decreased risk of response to hepatitis B vaccine among haemodialysis patients (overall risk ratio: 1.0, 95% confidence intervals: 0.92-1.1). The P-value was 0.13 for our test of study heterogeneity.

CONCLUSION

There is no significant link between dialysis mode and seroresponse to hepatitis B virus vaccine in dialysis population.

HBsAg seropositive status and survival after renal transplantation: meta-analysis of observational studies

The natural history of hepatitis B virus (HBV) infection after renal transplantation (RT) remains unclear. We conducted a systematic review of the published medical literature on the impact of HBV surface antigen (HBsAg) seropositivity on survival of RT recipients. We used the random effects model of DerSimonian and Laird to generate a summary estimate of the relative risk for mortality and graft loss in HBsAg positive RT recipients across the published studies. We identified six observational studies (6050 unique patients); all of them being cohort, retrospective studies. Pooling of study results demonstrated that HBsAg in serum was an independent and significant risk factor for death after RT; the summary estimate for relative risk was 2.49 with a 95% confidence interval (95% CI) of 1.64-3.78. A test for homogeneity of the relative risk across the studies gave a p-value of <0.0001. HBsAg seropositivity was an independent and significant risk factor for graft failure after RT; the summary estimate was 1.44 with a 95% CI of 1.02-2.04 (homogeneity test, p <0.0001). This meta-analysis shows that HBsAg positive RT recipients have an increased risk for mortality and graft failure compared to seronegative patients.

Review article: hepatitis C virus and calcineurin inhibition after renal transplantation

The impact of hepatitis C virus on patient and graft survival after renal transplantation remains controversial. However, recent studies have given emphasis on the detrimental role of hepatitis C on long-term patient and graft survival after renal transplantation. Various mechanisms can promote the lower survival in hepatitis C virus-positive recipients, i.e. post-transplant diabetes mellitus, liver disease and infections. Novel evidence has been accumulated showing the inhibitory activity of ciclosporin on the hepatitis C virus replication rate in human hepatocytes; ciclosporin has been shown in vitro to suppress hepatitis C virus replication as effectively as interferon alpha. This effect has not been seen with tacrolimus and is separate from its immunosuppressive activity. Data from patients with normal kidney function or after bone marrow transplantation show that ciclosporin inhibits hepatitis C virus replication. It appears that the progression of liver fibrosis is slower in hepatitis C virus-positive liver transplant recipients treated with ciclosporin than tacrolimus. In contrast, the clinical outcome of hepatitis C in hepatitis C virus-positive patients after liver transplantation treated with ciclosporin vs. tacrolimus has given mixed results. No information after renal transplantation is available. Various parameters can promote the worsening of hepatitis C after renal transplantation but choice of calcineurin inhibition is one of the few risk factors that can potentially be modified by the physician. Prospective, comparative trials of ciclosporin and tacrolimus with large size and adequate follow-up after renal transplantation are in progress.

Protection from cardiac injury by induction of heme oxygenase-1 and nitric oxide synthase in a focal ischaemia-reperfusion model

The enzymes heme oxygenase (HO) generate carbon monoxide (CO) in living organisms during heme degradation. Carbon monoxide has recently been shown to dilate blood vessels and to possess anti-inflammatory properties. It is also known that nitric oxide (NO) donors ameliorate cardiac ischaemia-reperfusion injury in experimental models of global or focal ischaemia-reperfusion (FIR). The two gaseous mediators share the same mechanism of action via the stimulation of soluble guanylyl cyclase and the increase in cellular levels of cyclic GMP. We studied the effects of manipulating the HO system and the possible interaction between CO and NO in an experimental in vivo model of FIR in the rat heart. FIR-subjected rats had necrotic area in the left ventricle, ventricular arrhythmias and a shortening of survival time in comparison to sham-operated animals. Resident mast cells underwent a heavy degranulation, malonyldialdehyde was produced by myocardial cell membranes, and tissue calcium levels were increased. High levels of myeloperoxidase were also detected, suggesting a FIR-related inflammatory process. In animals pre-treated with the HO-1 inducer, hemin, all the biochemical and morphometric markers of FIR were minimized or fully abated. Consistently, the biochemical and morphometric markers of FIR were reversed in rats treated with the HO-1 blocker, ZnPP-IX, prior to hemin administration. Pre-treatment with hemin significantly increases the expression and activity of both cardiac HO-1 and iNOS, suggesting that CO and NO cooperate in the cardioprotective effect against FIR-induced damage, and that there is a therapeutic synergism between NO-donors and CO-releasing molecules, via the common stimulation of increase in cGMP levels and decrease in calcium overload.

Occult hepatitis B virus infection in dialysis patients: a multicentre survey

BACKGROUND

The epidemiology and clinical significance of occult hepatitis B virus infection (serum hepatitis B surface antigen-negative patients with detectable hepatitis B virus viraemia in serum) remains controversial with only limited information about its prevalence in patients on long-term dialysis.

AIM

To address the epidemiology of occult HBV infection in a large cohort of dialysis patients.

METHODS

We screened a large cohort (n = 585) of Italian chronic dialysis patients; from this population, a group of hepatitis B virus surface antigen seronegative patients (n = 213) was tested by Amplicor hepatitis B virus Monitor Test to detect hepatitis B virus viraemia (hepatitis B virus-DNA) in serum.

RESULTS

Occult hepatitis B virus infection was absent (zero of 213 = 0%). Persistent hepatitis B virus surface antigen carriage was less frequent than anti-hepatitis B virus core antibody (anti-hepatitis B core antigen) seropositive status in this study group [1.88% (11 of 585) vs. 36% (216 of 585), P = 0.0001]. No dialysis patients seropositive for anti-hepatitis B core antibody in serum (zero of 123 = 0%) had detectable hepatitis B virus-DNA by polymerase chain reaction technology. No significant association between abnormal biochemical liver tests and serum anti-hepatitis B core antibody was noted in our population. Nominal logistic regression analysis demonstrated an independent and significant relationship between anti-HCV antibody and anti-hepatitis B virus core antibody in serum (Wald chi-square 16.06, P = 0.0001). The rate of seropositive patients for anti-hepatitis B virus core antibody was higher among study patients than controls with normal renal function [36.9% (216 of 585) vs. 21.4% (59 of 275), P = 0.0001]; this difference partially persisted after correction for demographic parameters, and viral markers.

CONCLUSION

In conclusion, occult hepatitis B virus was absent in our study group. Anti-hepatitis B core antibody was significantly related to presence of anti-HCV antibody supporting shared modes of transmission. Clinical studies based on molecular biology techniques provided with higher sensitivity are planned.