By Liz Highleyman

Due to overlapping transmission routes, many people are dually infected with both hepatitis B virus (HBV) and hepatitis C virus (HCV).

In a poster presentation this week at the 48th International Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington, DC, Italian researchers presented data confirming prior research showing that the presence of HBV interferes with HCV replication.

The investigators performed long-term clinical and virological follow-up of 29 chronic hepatitis C patients with HBV superinfection and 29 HCV negative individuals with acute hepatitis B. Patients in the 2 groups were matched for age (+/- 5 years), sex, and HBV risk factors.

Results

• At the first observation, HBV-HCV coinfected patients and HBV monoinfected individuals had similar HBV DNA viral load (mean 7.1 vs 1.6 x 108) and a similar trend towards becoming HBV negative (HBV clearance).

• Severe acute hepatitis B was more frequent in the HBV-HCV coinfected group than in the HBV monoinfected group (34.5% vs 6.9%; P < 0.05).

• Of the 28 patients in the HBV-HCV superinfection group who were still alive at the end of acute illness (1 died of sub-acute progressive hepatitis), 24 (85.7%) were followed for 2-6 years (median 5 years):

• 21 of these 24 patients became hepatitis B surface antigen (HBsAg) negative (87.5%);

• 2 progressed to HBsAg positive chronic hepatitis (8.3%);

• 1 underwent liver transplantation (4.1%).

• Data on HCV RNA levels before the development of acute hepatitis B and every 12 months thereafter were available for 19 patients:

• All became HCV RNA negative during the acute phase of hepatitis B (100%);

• 16 patients still had undetectable plasma HCV RNA after 1 year (84.2%);

• 9 still had undetectable HCV RNA after 2 years (47.4%);

• 6 still had undetectable HCV viral load after 3-6 years (31.6%).

• The 6 patients who remained persistently HCV RNA negative during follow-up were compared with the 13 who experienced reactivation of HCV replication:

• During the acute phase of hepatitis B, there were no observed differences in HBV viral load (P = 0.4);

• Serum ALT values, however, were higher in the persistently HCV negative subgroup (mean 5291 vs 2208; P < 0.01).

Based on these findings, the researchers concluded, "HBV superinfection in HCV chronic carriers was associated with a strong inhibition [of] HCV replication," especially in 6 patients with marked hepatonecrosis who fully cleared chronic HCV infection.

Second Univ. of Naples, Naples, Italy; A.O. San Sebastiano e Sant'Anna Caserta, Caserta, Italy.

10/31/08

Reference
E Sagnelli, N Coppola, M Pisaturo, and others. HBV Superinfection in Chronic HCV Carriers: Clinical and Virological Long-Term Follow-Up Study. 48th International Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2008). Washington, DC. October 25-28, 2008. Abstract V-1628.