Whether preemptive anti- hepatitis B virus (HBV) therapy should be considered in all hepatitis B surface antigen (HBsAg)-negative patients with occult HBV infection receiving alemtuzumab containing chemotherapy is uncertain. We determined the outcome and effect on HBV-specific immunity of an alemtuzumab-containing chemotherapy regimen in occult HBV-infected patients. Twenty-one consecutive occult HBV-infected patients treated with an alemtuzumab containing chemotherapy regimen were studied. T cell reactivity to HBV antigens and -peptides were quantified by ELISpot and the T cell subset by flow cytometry. Six of the 21 patients (28.6%) developed HBsAg seroreversion. The median (range) time to development of HBsAg seroreversion after the end of chemotherapy was 1.8 months (0.2-2.3 months). Direct sequencing showed that the occult HBV infection of all six patients (100%) was reactivated. These six patients developed severe HBV-related hepatitis. At the end of follow-up, four of these six patients (66.7%) had become negative for HBsAg again. Recovery of CD4+ T cell count and CD4+T cell reactivity against hepatitis B core antigen (HBcAg) occurred 9 months after the end of chemotherapy. Loss of HBsAg occurred after recovery of the CD4+T cell count and increased CD4+T cell reactivity against HBcAg 9 months after the end of chemotherapy.
Conclusion: An alemtuzumab-containing chemotherapy regimen is associated with a high risk of reactivation of occult HBV infection. Suppression of HBV immunity by an alemtuzumab-containing chemotherapy regimen would persist until 9 months after the end of chemotherapy. In occult HBV-infected patients receiving an alemtuzumab-containing chemotherapy regimen, preemptive anti-HBV therapy should be continued until 9 months after the end of chemotherapy, when recovery of HBV immunity has occurred.