Several cases of TNF antagonist-related reactivation of hepatitis B have been reported. Here, we describe 4 cases in patients with spondyloarthropathies. Long-term monitoring of the hepatitis B virus (HBV) load is in order in HBV-positive patients treated with TNF antagonists.

There were 3 men and 1 woman, aged 30–40 years. Follow-up ranged from 1 to 5 years. In 2 patients, the HBV infection was not discovered until the pre-TNF antagonist therapy workup. A viral load increase was noted after a TNF antagonist was added to methotrexate in 2 patients, whose viral load values returned to baseline after the introduction of the antiviral agent lamivudine. Lamivudine was started at the same time as the TNF antagonist in the other 2 patients, whose viral loads remained undetectable. Escape phenomenon requiring a switch to another antiviral agent was required in 1 patient after more than 4 years of treatment with 3 TNF antagonists.

These 4 case reports illustrate the challenges raised by latent HBV infection in patients who require TNF antagonist therapy. They support routine HBV testing before treatment initiation, followed in HBV-positive patients by viral load monitoring. Antiviral therapy can be used preventively and should be given if the viral load increases under TNF antagonist therapy. In patients on antiviral therapy, viral load monitoring should be continued, given the risk of escape phenomenon after several years.