HEPATITIS C INFECTION IN THE TRANSPLANT RECIPIENT

Effect of alcoholic liver disease and hepatitis C infection on waiting list and posttransplant mortality and transplant survival benefit

Disease-specific analysis of liver transplant survival benefit, which encompasses both pre- and posttransplant events, has not been reported. Therefore, we evaluated the effect of alcoholic liver disease (ALD) and hepatitis C virus (HCV) infection on waiting list mortality, posttransplant mortality, and the survival benefit of deceased donor liver transplantation using United States data from the Scientific Registry of Transplant Recipients on 38,899 adults placed on the transplant waiting list between September 2001 and December 2006. Subjects were classified according to the presence/absence of HCV and ALD. Cox regression was used to estimate waiting list mortality and posttransplant mortality separately. Survival benefit was assessed using sequential stratification. Overall, the presence of HCV significantly increased waiting list mortality, with a covariate-adjusted hazard ratio (HR) for HCV-positive (HCV+) compared with HCV-negative (HCV-) HR = 1.19 (P = 0.0001). The impact of HCV+ was significantly more pronounced (P = 0.001) among ALD-positive (ALD+) patients (HR = 1.36; P < 0.0001), but was still significant among ALD-negative (ALD-) patients (HR = 1.11; P = 0.02). The contrast between ALD+ and ALD- waiting list mortality was significant only among HCV+ patients (HR = 1.14; P = 0.006). Posttransplant mortality was significantly increased among HCV+ (versus HCV-) patients (HR = 1.26; P = 0.0009), but not among ALD+ (versus ALD-) patients. Survival benefit of transplantation was significantly decreased among HCV+ compared with HCV- recipients with model for end-stage liver disease (MELD) scores 9-29, but was significantly increased at MELD >or=30. ALD did not influence the survival benefit of transplantation at any MELD score.

CONCLUSION

Except in patients with very low or very high MELD scores, HCV status has a significant negative impact on the survival benefit of liver transplantation. In contrast, the presence of ALD does not influence liver transplant survival benefit.

Prevalence of hepatitis C virus infection and related risk factors among Iranian haemodialysis patients

Hepatitis C virus (HCV) infection is common among patients undergoing haemodialysis, and liver disease is an important cause of morbidity and mortality in this population. Management of HCV-related liver disease is a major health concern in patients with end-stage renal disease (ESRD) undergoing haemodialysis. To investigate the prevalence of HCV infection in patients on haemodialysis and its associated risk factors, we conducted a prospective case series study of 838 patients on haemodialysis in Tehran, Iran. Patients were selected randomly (cluster sampling) and all were screened for anti-HCV antibodies, using ELISA 3rd generation and confirmed by using RIBA 2nd generation. We found that 111 patients (13.2%) were infected. By applying univariate analysis, longer duration on haemodialysis (P = 0.000), more weekly dialysis sessions (P = 0.03), history of blood transfusion (P = 0.03) and history of previous renal transplantation (P = 0.01) were found to be associated with a higher rate of HCV infection. Multivariate analysis revealed that only length of time on dialysis (P = 0.000) and history of blood transfusion (P = 0.02) were significantly associated with HCV infection. The more the units transfused, the higher the rate of HCV infection. Our results suggest that early transplantation and avoidance of blood transfusion, as much as possible, are the two most important practical interventions to reduce the HCV exposure rate in our patients on haemodialysis.

Hepatitis C virus infection and non-Hodgkin lymphoma: results of the NCI-SEER multi-center case-control study

Several studies have noted elevated hepatitis C virus (HCV) prevalence among patients with non-Hodgkin lymphoma (NHL), suggesting that HCV infection increases NHL risk through chronic immune stimulation. Population-based data from the U.S. are lacking. In a population-based case-control study of NHL in the United States, we identified HCV infection using an enzyme immunoassay, confirmed by recombinant immunoblot assay or HCV RNA detection. The association between HCV and NHL was assessed using logistic regression, adjusting for demographic factors, illicit drug use or medical history. Thirty-two of 813 (3.9%) NHL cases and 14 of 684 (2.1%) controls were HCV-infected [odds ratio (OR) 1.96, 95%CI 1.07-4.03]. For separate NHL subtypes, numbers were limited. Nonetheless, positive associations were noted for follicular (OR 2.46, 95%CI 1.01-5.81), marginal zone (3.99, 0-13.6) and mucosa-associated lymphoid tissue (2.04, 0-7.20) NHLs. For all NHLs combined, the HCV-NHL association changed little after adjustment for sex, age, race and study center (OR 1.89, 95%CI 1.00-4.00). HCV was common in controls who had injected drugs (40%) or used other illicit drugs (6.5%), but adjustment for drug use did not affect the HCV-NHL association (OR 1.87, 95%CI 0.95-4.10). Transfusion history was unrelated to HCV status, and adjustment for this exposure did not attenuate the HCV-NHL association (OR 2.15, 95%CI 1.12-4.76). Excluding 4 subjects with a history of hemodialysis or 3 subjects with organ transplants also did not affect the results. Our study demonstrates an association between HCV infection and NHL in the United States. HCV infection may be a cause of NHL.

Infections in recipients of kidney transplants

A review of infections in kidney transplant recipients is presented in this article, beginning with a discussion of the pretransplant infectious diseases evaluation and an overview of the timing of infectious posttransplant, and then focusing on individual types of infection.

Early detection of hepatitis C allograft reinfection after orthotopic liver transplantation: a molecular and histologic study

After orthotopic liver transplantation (OLT), patients with chronic hepatitis C virus (HCV) infection show nearly universal persistence of viremia and reinfection of the liver, but identifying the point at which the liver is reinfected morphologically can be difficult. One tool that may potentially be useful to detect reinfection is reverse transcriptase-polymerase chain reaction (RT-PCR), which has proven to be highly sensitive for detecting HCV RNA in formalin-fixed paraffin-embedded liver tissue. Our purpose was to gain insight into the time frame of HCV reinfection by assaying for HCV RNA in serial posttransplant liver biopsy specimens. Our study population consisted of 14 patients who underwent liver transplantation for hepatitis C and had confirmed HCV RNA in pretransplant serum, absence of HCV RNA in donor livers, and available consecutive posttransplant liver allograft specimens. We performed RT-PCR for HCV RNA in serial posttransplant liver biopsy specimens, beginning at 1 week until at least one biopsy from each tested positive. HCV RNA was detected in liver tissue by RT-PCR in 1-week post-OLT liver samples in 6 of 14 (42.8%) patients, the earliest being 5 days post-OLT. Eventually, each of the remaining eight samples became RT-PCR positive as well; the first detections occurred in these at 3 weeks (three cases), 4 weeks (three cases), 48 weeks (one case), and 144 weeks (one case). Histologic identification of hepatitis C recurrence was relatively insensitive in relation to these molecular data. These data suggest that (1) HCV RNA reinfection is nearly universal after liver transplantation in patients with chronic hepatitis C infection, (2) molecular reinfection by HCV occurs at a variable interval post-OLT, with the majority of allograft livers reinfected as early as 1 week, and (3) morphologic features of hepatitis C are usually appreciable at the time of "molecular" recurrence.

Hepatitis C and renal failure

Chronic hepatitis C virus (HCV) infection is common among patients with chronic renal failure. This chronic viral infection can result in significant morbidity and mortality. Liver failure from chronic hepatitis C is one of the leading causes of death among long-term survivors of renal transplantation. HCV infection also can be a cause of glomerulonephritis and nephrotic syndrome. Recognition of these conditions is important to optimize the management of these patients.

Diagnostic tools in the evaluation of patients with viral hepatitis undergoing liver transplantation

Familiarity with the diagnostic parameters of viral hepatitis is imperative in the liver transplantation arena. Chronic viral hepatitis B and C are among the most common categories of end-stage liver disease. The preoperative diagnosis, determination of recurrent infection, and the assessment of antiviral therapeutic efficacy are dependent on appropriate virological testing. Furthermore, liver transplant personnel are at a high risk for parenterally transmitted viral hepatitis infection. Knowledge and understanding of the serological patterns of acute and chronic viral hepatitis, as well as recognition of the immune status for one or more of these viruses, will facilitate prevention and treatment of viral hepatitis for these health care providers.

Infections After Organ Transplantation

Over the last ten to fifteen years medical and surgical advances have led to lower rates of infection and infection-related mortality in transplant recipients. Despite these advances, the process whereby one diagnoses and manages infectious problems in transplant patients has become increasingly complex. Evaluation of transplant patients with infections requires a good understanding of the intricacies of modern immunosuppressive therapy and both the typical and atypical clinical manifestations of many conventional and opportunistic pathogens. In particular, it is incumbent upon the clinicians caring for transplant patients to be familiar with the biology of cytomegalovirus and other herpes viruses, and of the prophylactic strategies that have evolved to lessen the burden of disease from these agents. Thorough knowledge is also required of common fungal pathogens and the viruses that cause chronic hepatitis. Transplant patients also should always be evaluated in the temporal context of their transplant operation, because different diseases are prevalent at different times after transplantation. Since immunosuppressive drugs modify the clinical presentation of infections is important to maintain clinical vigilance and attend to even minor new symptoms. This chapter is designed to provide a relatively concise overview of transplant infections for intensivists or other clinicians who encounter transplant patients in their practice. The references encompass much of the classic transplant infectious disease literature; they are included, not only for citation, but as a bibliography for further study.

Infections in solid-organ transplant recipients

Solid-organ transplantation is a therapeutic option for many human diseases. Infections are a major complication of solid-organ transplantation. All candidates should undergo a thorough infectious-disease screening prior to transplantation. There are three time frames, influenced by surgical factors, the level of immunosuppression, and environmental exposures, during which infections of specific types most frequently occur posttransplantation. Most infections during the first month are related to surgical complications. Opportunistic infections typically occur from the second to the sixth month. During the late posttransplant period (beyond 6 months), transplantation recipients suffer from the same infections seen in the general community. Opportunistic bacterial infections seen in transplant recipients include those caused by Legionella spp., Nocardia spp., Salmonella spp., and Listeria monocytogenes. Cytomegalovirus is the most common cause of viral infections. Herpes simplex virus, varicella-zoster virus, Epstein-Barr virus and others are also significant pathogens. Fungal infections, caused by both yeasts and mycelial fungi, are associated with the highest mortality rates. Mycobacterial, pneumocystis, and parasitic diseases may also occur.