March 16, 2022
By Erica Kaufman West, MD
Hepatitis B core antibody (HBcAb) positivity indicates prior exposure but not necessarily active infection. Patients with HBcAb-only positivity either have a false-positive HBcAb or have some form of convalescent hepatitis B virus (HBV) infection. While renal transplant patients with hepatitis B surface antigen (HBsAg) positivity with HBcAb positivity are known to have a high risk of reactivation, those who are HBsAg-negative and HBcAb-positive fall into an unclear risk, with HBV reactivation rates between 1.9% and 9.6% post renal transplant cited in the literature. Current American Association for the Study of Liver Diseases (AASLD) guidelines recommend monitoring HBcAb-positive patients post-transplant with alanine aminotransferase and HBV DNA every 3 months, with the consideration of starting antiviral therapy. In general, without the use of anti-CD20 treatment, AASLD and the American Society of Transplantation Infectious Disease Community of Practice (AST ID COP) recommend against routine antiviral prophylaxis, but in which patients to start is also up for debate. Guidelines do recommend antiviral treatment in post-transplant patients taking anti-CD20 medication (e.g., rituximab).
Reporting their results in Transplant Infectious Disease, researchers performed a multicenter retrospective cohort study of adult kidney transplant patients who were HBcAb-positive. HIV-positive and HCV-positive patients were excluded; 161 met inclusion criteria. The primary outcome was HBV reactivation, and secondary outcomes were 1-year graft survival, 1-year all-cause mortality, biopsy-proven acute rejection, and antibody-medicated rejection. Of the 161 patients, 147 did not receive HBV prophylaxis and 14 did. Rabbit anti-thymocyte globulin, steroid usage, and triple maintenance (tacrolimus, mycophenolate, and prednisone) usage were all similar between the two groups. Also similar was HBsAb-positive status, with 79.6% and 78.6%, respectively, being positive. The overall reactivation rate was 3.7% with no difference between the groups. The one patient who reactivated in the prophylaxis group was on antivirals for 1,064 days post-transplant and reactivated 504 days after discontinuing.
There were no differences in the secondary outcomes between the two groups. In the six reactivation cases, four had HBsAb titers considered protective in the general population. Interestingly, almost all of the patients who went on to reactivate had delayed graft functioning (defined as requiring dialysis within 7 days post-transplant), which was the only significant risk factor for reactivation. The findings affirmed guidelines provided by AASLD and AST ID COP: HbsAg-negative and HBcAb-positive patients do not require antiviral prophylaxis. However, the authors do recommend that these patients be followed by a hepatologist so that appropriate testing is timely to minimize risk of advanced liver disease.