Immune predictors of hepatitis B surface antigen seroconversion in patients with hepatitis B reactivation

BackgroundHepatitis B surface antigen (HBsAg) seroconversion is sometimes observed in hepatitis B reactivation (rHBV), probably due to immune resetting and differentiation. AimsTo investigate sequential immune differentiation and abrogation of tolerance in patients with rHBV who achieved HBsAg seroconversion. MethodsWe included 19 patients with chronic hepatitis B (CHBV; HBV DNA log10(3-8)), 67 with rHBV (raised ALT [>5XULN], HBV DNAlog10(4-8)) and 10 healthy controls. Immune differentiation, tolerance and functional status of CD4, CD8, T regulatory cells (Tregs), B cells and follicular T helper (Tfh) cells were assessed at baseline and 24 weeks. ResultsAt 24 weeks, 81% rHBV (n = 67) lost HBV DNA and HBeAg (41%), and 12 (19%) lost HBsAg and made anti-HBs titers >10 IU/ml. rHBV patients had higher Th1/17, T-EM, Tfh, Tfh1/17, plasma and ATM B cells, and lower Tregs, Th2, Th17 and TEMRA expression. rHBV showed lower PD1, TIM3, LAG3, SLAM and TOX compared to CHBV. There was a significant increase in CD8, CD8EM, Tfh, Tfh1/17 and plasma B cells in seroconverters than non-seroconverters. At 24 weeks, we also observed increased plasma B cell frequency in seroconverters. While non-seroconverters showed higher expression of PD1, TIM3, LAG3, SLAM and TOX on CD4/CD8 T cells, blockade of PD1, TIM3, LAG3 and CTLA4 significantly enhanced IFN-gamma, TNF-alpha, IL-4 and IL-21 expression on CD4/CD8 and Tfh cells in non-seroconverters. ConclusionsNon-seroconverters have increased inhibitory markers on CD4/CD8 T cells. There is a critical play of CD8, Tfh and B cells and subsets in seroclearance, along with checkpoint molecules as a potential therapy for non-seroconverters in HBV infection.