Clinical Significance of Occult HBV in People with HIV

Clinical Significance of Occult HBV in People with HIV

By Liz Highleyman

Some research has shown that coinfection with HIV and hepatitis B virus (HBV) is associated with worse liver disease progression, but the clinical relevance of low levels of occult or "hidden" HBV is unclear.

Occult infection is diagnosed when HBV DNA is detected in individuals with HBV core antibodies (anti-HBc) but without HBV surface antigen (HBsAg).

V. Lo Re and colleagues performed a seroprevalence study in subjects randomly selected from among 699 HBsAg-negative/anti-HBc-positive patients with HIV enrolled in the Penn CFAR Database and Specimen Repository.

Repeat HBsAg and anti-HBc testing was performed on banked serum from randomly selected subjects. The presence of HBV viremia was qualitatively detected using a sensitive nucleic acid amplification assay (HBV TMA assay; Gen-Probe, Inc) with about 99% specificity and 95% sensitivity in detecting HBV DNA at IU/mL (15-30 genome equivalents). The researchers used the AST-to-platelet ratio index (APRI) score to identify patients with significant liver fibrosis (defined as APRI > 1.5).

Results

Of 179 subjects, 17 (10%; 95% CI 5%-14%) had occult HBV.

HBV DNA-negative patients had higher median ALT and AST levels compared to subjects with occult HBV (38.5 vs 25; P = 0.01 and 32 vs 40; P > 0.5, respectively).

Patients with occult HBV were less likely to be using anti-HIV drugs that are also active against HBV, such as 3TC (lamivudine; Epivir), emtricitabine (Emtriva; FTC), or tenofovir (Viread).

Regression analysis controlling for chronic hepatitis C and alcohol use found no differences in ALT and AST levels based on occult HBV status.

The proportions of subjects with significant fibrosis were not different in the groups with and without occult HBV (2 [12%] vs 15 [25%]; P > 0.5).

Conclusion

In conclusion, the researchers wrote, "Among HIV patients, occult HBV was not associated with elevated transaminase levels or significant liver fibrosis by APRI score. Longitudinal studies are needed to determine if occult HBV is associated with more severe fibrosis."

"It may be that low levels of occult HBV do not induce clinically significant liver inflammation," Lo Re said during his oral presentation, "but the long-term clinical implications remain unclear."

He noted that past data suggest that HBV levels may fluctuate over time, so failure to detect viral genetic material at a given point in time does not necessarily mean a person does not have occult HBV.

Lo Re added that based on what is known to date, it is hard to make recommendations as to whether HIV positive individuals should be tested, treated, or vaccinated against hepatitis B until further longitudinal data are available.

Univ. of Pennsylvania Sch. of Med., Philadelphia, PA; Gen-Probe Inc., San Diego, CA.

10/03/06

Reference
V Lo Re, J Kostman, R Gross, and others. Clinical Significance of Occult Hepatitis B Virus Infection in HIV Patients. 46th ICAAC. San Francisco, CA. September 27-30, 2006. Abstract H-1062.

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