Interferon treatment for hepatitis C virus infection in patients on haemodialysis

Histopathological features of hepatitis C in renal transplant candidates [see comment]

BACKGROUND

Although hepatitis C virus (HCV) infection is common in renal transplant candidates, its clinical significance remains unclear in this population. Little detailed information is available about the histological severity of HCV infection in these patients. We evaluated the liver biopsy features of chronic HCV in a large population of renal transplant candidates and investigated associations between histopathological changes and host- and virus-related factors.

METHODS

Thirty-seven patients seropositive for anti-HCV with chronic renal failure (CRF) referred to UCLA Medical Center for kidney or kidney/liver transplantation during the period 1992-1997 were included. HCV genotype and viral load were measured. A multivariate analysis by logistic regression model was performed: age, gender, race, HCV load and genotype, CRF level, aspartate and alanine aminotransferase activity, duration of HCV infection, underlying nephropathy, and alcohol abuse were independent variables; liver histology score was assumed a dependent variable.

RESULTS

Liver disease was present in all HCV-infected patients. Logistic regression analysis revealed that histological damage was (P = 0.0017) independently associated with the CRF level; the severity of liver disease, as shown by univariate analysis, being significantly higher in CRF patients not requiring dialysis than among dialysis population. All patients on dialysis showed mild or moderate necroinflammatory activity; the majority (22/28 = 79%) of these individuals had fibrosis, three (3/28 = 11%) dialysis patients had established cirrhosis. Thirty-one (84%) of 37 patients were tested by polymerase chain reaction, 25 (81%) patients had detectable HCV RNA in serum, the mean HCV load among viremic patients was 10.9x10(5) copies/ ml. The most frequent HCV genotypes were la (8/24 = 33%) and 1b (7/24 = 29%), followed by genotype 2b (3/24 = 12%).

CONCLUSIONS

Pathological changes on liver biopsy were observed in all HCV-infected patients awaiting renal transplantation. The severity of histologic damage observed on liver biopsy was less in dialysis than predialysis CRF patients. All dialysis patients had mild or moderate necroinflammatory activity; fibrosis was frequent with 11% of them having cirrhosis. The HCV viral load was rather low; no relationship between liver histology changes and virological features of HCV or aminotransferase activity was apparent. Further studies with repeat liver biopsies after kidney transplantation to observe the evolution of HCV-related liver disease after immunosuppressive therapy are indicated. We suggest including liver biopsy in the evaluation of the HCV-infected renal transplant candidate.

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.

Pharmacokinetics of natural human IFN-alpha in hemodialysis patients

A pharmacokinetic study of natural human interferon-alpha (IFN-alpha) was conducted in hemodialysis patients. Natural human IFN-alpha was intramuscularly (i.m.) administered to 8 hemodialysis patients at a single dose of 5 million IU and to 7 patients undergoing hemodialysis at the same dose once daily for 5 successive days. The serum antiviral activity was determined by a cytopathic effect bioassay. In the single dose study, the serum antiviral activity reached a maximum (Cmax) of 56.4 +/- 33.3 IU/ml at 8.3 +/- 2.7 h after dosing, and the area under the serum concentration-time curve (AUC0-24h) was 957.2 +/- 601.8 IU h/ml. The Cmax and AUC0-24h values at day 5 following the repeated dosing were both 2.6-fold higher than those of day 1, and the serum antiviral activity reached a steady state within 3 days after initiation of repeated administration. The serum antiviral activity in hemodialysis patients showed a tendency to increase compared with that in the subjects with normal renal function, but the magnitude of the differences was not great. In one nonhemodialysis patient with poor renal function (creatinine clearance < 30 ml/min), no increases in serum antiviral activity owing to repeated dosing were observed. The main adverse events seen were fever (4 of 13, 30.8%), leukopenia (3 of 13, 23.1%), and fatigue (2 of 13, 15.4%). These results suggest that dosage modifications of natural human IFN-alpha are unnecessary for patients with low renal function, even those undergoing hemodialysis.

Treatment of hepatitis C infection in patients with renal disease

Hepatitis C virus infects 20-40% of the end-stage renal disease population, and has been associated with essential mixed cryoglobulinemia and several forms of immune-complex glomerulonephritis. Overall, treatment with interferon alpha has been disappointing, although certain situations may benefit from dosing regimens that differ in the amount of drug and duration of treatment from the conventional interferon doses currently recommended for non-renal patients.