Hepatitis B virus among hematopoietic stem cell transplant recipients: antiviral impact in seroconversion, engraftment and mortality in a Latin American center.

BACKGROUND: Hepatitis B virus (HBV) infection is a worldwide concern with a broad distribution. In immunosuppressed populations, such as solid organ and hematopoietic stem cell transplant (HSCT) recipients, it can reactivate leading to acute hepatic failure. Different risk factors are known for higher rates of reactivation, and entecavir, tenofovir, and lamivudine are often used for prophylaxis and treatment. However, data regarding the impact of antiviral drugs in neutrophil and platelet engraftment are still unknown and concerns the management of viral hepatitis post-HSCT.

METHODS: We performed a single-center retrospective, observational study reviewing medical records of patients referred for hematopoietic stem cell transplant from 2010 to 2017, which were also HBV infected, aiming to describe outcomes related to antiviral treatment and also the impact on platelet and neutrophil recovery after transplant. A secondary goal consisted of analyzing the impact of HBV infection in early and late mortality post-HSCT. The study included patients with positive blood bank screening for Hepatitis B infection (HBsAg, Anti-HBc or HBV-NAT), confirmed later on by a laboratory routine serology.

RESULTS: a total of 1132 hematopoietic stem cell recipients were assessed between 2010 and 2017. 86 patients were confirmed to have HBV infection, of which 6 were HBsAg-positive, 20 were isolated anti-HBc-positive and 60 had resolved infection (anti-HBc-positive and anti-HBs-positive). With regards to prophylaxis, 19 patients underwent HSCT on HBV antiviral therapy or prophylaxis: 2 were HBeAg-positive, 3 were HBeAg-negative and HBV-DNA was only detectable in 3 of them. Moreover, one patient had an occult HBV infection. Regarding therapy, 9 patients were on entecavir, 6 patients on lamivudine, 2 on tenofovir and 2 of them on a combination of tenofovir + lamivudine due to HIV co-infection. Reverse seroconversion was not identified in any patients receiving antiviral therapy or prophylaxis, but it was detected in one patient with occult hepatitis B and another with resolved infection. No severe side effects led to therapy discontinuation in the treated group, which also did not have any significant delay in neutrophil or platelet engraftment when compared to patients without antiviral therapy. In addition, the only factors associated with increased mortality were transplant onset after 50 years, allogeneic transplant and myeloablative conditioning regimens. Interestingly, the presence of HBsAg or detectable HBV-DNA were not related to worse outcomes, neither the use of Rituximab. In multivariate analysis, the use of antiviral therapy, the occurrence of graft-versus-host disease or CMV reactivation also were not linked to increased mortality.

CONCLUSIONS: to sum up, HBV serology, ALT and HBV-DNA monitoring are essential to detect hepatic flares earlier, even in populations with chronic inactive hepatitis, due to the possibility of later seroconversion. HBV infection was not related to increased 2-year mortality post-transplant. Antiviral prophylaxis did not cause any important clinical or laboratory side effects that could demand discontinuation, and its use was not associated with later neutrophil and platelet engraftments.