Kinetics of Hepatitis B virus load during haemodialysis sessions and α-interferon: a prospective study.

BACKGROUND It has been reported a slow progression of hepatitis B in patients undergoing maintenance dialysis, and a role of dialysis session per se has been suggested. The aim of the present study is to evaluate the kinetics of the hepatitis B viral load (HBV DNA) in serum during haemodialysis sessions using a highly sensitive technique; the role of interferon-α in lowering HBV viral load in such patients was also investigated. METHODS HBV DNA was determined in 24 HBsAg positive patients on maintenance hemodialysis immediately before and after a 4-hour hemodialysis session, the same measurements were repeated 48 and 72 hours later. HBV DNA quantitation was performed by a novel RealTime PCR assay. Serum IFN-α levels were tested in parallel in a subset of HD sessions (n=40) by ELISA. RESULTS 20 (83%) HBsAg positive patients had detectable HBV DNA in serum. Positive status for HBV DNA in serum was not predicted by demographic, clinical or biochemical parameters. HBV load decreased in many patients after hemodialysis sessions 5.92 log10 IU/mL (95% CI, 5.34 to 6.28 log10 IU/mL) vs. 4.79 log10 IU/mL (95% CI, 4.23 to 6.15 log10 IU/mL) (P=0.02). A significant relationship between mean HBV DNA levels before dialysis and percentage reduction of HBV DNA during HD sessions occurred [F-test=5.41, rho (least squares)=0.307]. Increase of serum IFN-α levels was found in a minority (3/40=7%) of HD sessions. CONCLUSIONS Hemodialysis procedure gives reduction of HBV load in HBsAg chronic carriers; no relationship with IFN-α activity during HD sessions was found. The kinetics of HBV viremia in HD procedures could explain the low viral load which is typically observed in these patients. Further studies to identify the mechanisms responsible for reduction of HBV viremia during HD procedures are under way.