Abstract:

OBJECTIVES: To evaluate the predictive value of serum beta2-microglobulin (beta2m) levels for virological breakthrough in hepatitis B e antigen-negative chronic hepatitis B patients under long term lamivudine monotherapy. METHODS: Serum beta2m levels were calculated at baseline and every three months during lamivudine monotherapy in 25 patients with chronic hepatitis B, using microparticle enzyme immunoassay technology to investigate their association with biochemical, virological and histological outcome data. Cox proportional hazard models were used to investigate the association between serum beta2m levels and virological breakthrough. RESULTS: Seven of 25 (28%), nine of 25 (36%) and 14 of 25 (56%) chronic hepatitis B patients exhibited virological breakthrough at months 12, 24 and 36 of treatment, respectively. All chronic hepatitis B patients who did not show virological breakthrough in the follow-up period exhibited beta2m elevation in month 3 of treatment. The duration (in months) of serum beta2m elevation was significantly higher in the responders group than the nonresponders group (7.3 +/- 2.6 versus 3.8 +/- 3.4, P=0.02). In contrast to patients whose serum beta2m levels were increased at three months, patients whose beta2m levels were decreased had a 4.6 times higher risk of experiencing virological breakthrough (hazards ratio 4.6, 95% CI 1.22 to 17.36). When age, pretreatment serum alanine aminotransferase and hepatitis B virus DNA levels, and grade of liver disease were simultaneously included in the same Cox model, decreased beta2m status was still associated with increased risk of virological breakthrough (hazards ratio 12.2, 95% CI 1.28 to 116.8). CONCLUSIONS: In hepatitis B e antigen-negative chronic hepatitis B patients under long term lamivudine monotherapy, serum b2m levels at three months of treatment, compared with baseline levels, are good predictors of risk for virological breakthrough.