FRI-153
Potent hepatitis B core-specific B cell responses associate with
clinical parameters in untreated and virally suppressed chronic
HBV patients
Thomas Vanwolleghem1,2, Anthony Grooshuismink2, Kim Kreefft2,
Magdeleine Hung3, Nikolai Novikov3, Andre Boonstra2. 1Antwerp
University Hospital, Gastroenterology and Hepatology, Antwerp,
Belgium; 2Erasmus University Medical Center, Gastroenterology and
Hepatology, Rotterdam, Netherlands; 3Gilead Sciences, Biology, Foster
City, United States
Email: [email protected]
Background and aims: Exhaustion of virus-specific T cells is a
hallmark of chronic HBV (cHBV) infections, but the HBV-specific B cell
response is less well studied. Previously, we identified B cell-related
transcriptomic changes in blood and liver of cHBV patients in
different clinical phases. We now examined, the number, phenotype
and function of HBcAg-specific B cells during cHBV, in comparison to
HBsAg-specific B cells.
Method: Serum and PBMC were obtained from 137 cHBV patients,
both untreated (n = 114) belonging to different clinical phases as NUC
treated (n = 23), and 22 healthy HBsAg-vaccinated controls. The
phenotype of overall and HBV-specific B lymphocytes was studied by
FACS using DyLight650 and DyLight550 dual fluorescently labelled
HBsAg and HBcAg in combination with antibodies against CD3, CD10,
CD19, CD27, CD21, CD38, and FcRL5. In vitro anti-HBs and anti-HBc
antibody production was measured after polyclonal PBMC stimulation
by ELISPOT assays. Anti-HBs and anti-HBc antibodies were
measured in serum and in supernatant by ELISA.
Results: Serum levels of anti-HBc, but not anti-HBs antibodies
associate with the clinical phases of cHBV, characterized by
increasing titers in patients with ALT rise (p < 0.0001). In vitro, a
similar profile is seen for the number of spot-forming anti-HBcproducing
cells and their levels in the supernatant of these cultures
(p < 0.0001). Also the number of HBcAg-specific B cells in blood
followed this pattern (p = 0.0035). In contrast, HBsAg-specific B cells
showno typical numeric or functional changes in cHBV and are vastly
outnumbered by HBcAg-specific B cells in blood (92.8-fold, P <
0.0001). HBcAg-specific B-cells are enriched for a CD21- and CD21 +
CD27 + memory B cell profile compared to total B cells (3.6-fold and
2.0-fold, P < 0.0001 respectively), but demonstrate a less activated
phenotype (activation marker CD38: 0.8-fold, P = 0.0017; inhibitory
IgG co-receptor FcRL5: 2.3-fold, P < 0.0001). Interestingly, complete
viral suppression in the NUC cohort, led to reduced numbers of
HBcAg-binding B cells and in vitro production of anti-HBc antibodies
(all P < 0.05). For the total chronic HBV cohort, HBV DNA levels
positively correlated with in vitro anti-HBc production levels (r =
0.388, P = 0.0008) and with the number of HBcAg-binding B cells (r =
0.323 P < 0.05).
Conclusion: HBcAg-specific B cells vastly outnumber HBsAg-specific
B cells in blood of chronic HBV patients, are enriched for a classical
memory B cell phenotype and show no impairment with increasing
HBV DNA titers. 作者: StephenW 时间: 2019-4-17 18:39