Discussing the HBV & immune system interaction at different phases

2. HBV
Professor : Abdel Rahman A Mokhtar
Mansoura University – internal Medicine Dept
2019

3. The immune tolerant (IT) phase, the first phase of chronic
hepatitis B virus (HBV) infection, has historically been
perceived as a benign period in the natural history of this
disease.
Perinatal infection leads to a prolonged IT phase, with
transition to immune clearance with seroconversion to anti-
HBe in the second to third decade,
whereas immediate progression to immune clearance
usually occurs in newly infected children and adults.

4.  HBV is non - cytopathic , and therefore
hepatic damage due to HBV infection
results as a consequence of aggressive
activation of host immunity, aimed at
eradicating the virus.
Chisari FV. Curr Top Microbiol Immunol. 1996;206:149 -73.

5. HBV is not cytotoxic but destroys liver cells
indirectly by provoking an immunologic response
Kupffer cells
endocytose
viral antigens
and present
them bound to
MHC class II
molecules to T-
helper cells.
These CD4+ cells recognize
the antigens and release
cytokines that direct B-cell
and cytolytic T-cell (CTL)
activity.
CTLs recognize viral
peptides bound to MHC
class I molecules on
hepatocyte surfaces,
leading to destruction of
infected hepatocytes
Stimulated B
cells produce
specific
antibodies,
including
neutralizing
antibodies

6. Some individuals fail to
clear the virus and
progress to
CHB infection

9. • Immunological tolerance refers to the specific
immunological non-reactivity
(unresponsiveness) to an antigen due to a
previous exposure to the same antigen.
• While the most important form of tolerance is
non-reactivity to self antigens, it is possible to
induce tolerance to non-self antigens. When
an antigen induces tolerance, it is termed as
Tolerogens.

11. • Under normal physiological conditions,
the selection process ensures that the
immune system is stable without causing
autoimmune diseases.

12. • However, in some pathological situations, the
selection process can be used by pathogenic
microorganisms to escape the immune
clearance of the host for pathogens to
effectively continue to infect the human body.
• It has been postulated that HBV can use this
naturally occurring immune tolerance
pathway to maintain its persistent infection in
humans.

13. The IT phase is characterized by positive
hepatitis B e-antigen (HBeAg), high viremia
(typically >107–108 IU/mL), and normal alanine
aminotransferase (ALT) activity, but the hallmark
is no/ minimal necroinflammatory activity and no
fibrosis on liver histology.

14. The concept of immune tolerance phase being a
quiescent disease phase with an absence of
virus-specific T cells and minimal changes in liver
histology leads to the traditional recommendation
that :
This is an immune innert phase ( Benign) .
No need for treatment .
Monitoring only .
Yet ,,,,,,,,,,,,,,
This concept (of immune tolerance phase being a quiescent
disease phase with an absence of virus-specific T cells and
minimal changes in liver histology) is now increasingly being
challenged..

15. The efficacy of HBV vaccination within
the first year of life ,raises considerable
doubt that there is immune tolerance and
defects in T–B cell interactions.
In addition to several immunologic
studies that failed to prove immune
tolerance.
Mackie CO,et al., Hepatitis B immunization strategies: timing is everything.
Can Med Assoc J 2009; 180: 196–202.

17.  Studies performed in adenovirus infected mice have shown that T cell immunity
against hepatocytes could occur without elevation in serum ALT level
 Adoptive transfer of HBV-specific T cells can lead to significant inhibition of HBV
replication without increase in serum ALT through cytokine-mediated non-
cytopathic effect.
 Direct quantification of HBV-specific T cells in the blood and liver of CHB patients
have also shown that, in contrast to patients with acute hepatitis B , the quantity
of HBV-specific T cells does not correlate with ALT levels.
Instead, robust inflammatory events in the liver causing fluctuations in ALT levels,
demonstrated both in adult mice and in patients, are associated with
intrahepatic recruitment of granulocytes, monocytes, and non-antigen-specific T cells
Michelle Hong & Antonio Bertoletti Semin Immunopathol (2017) 39:643–652

20. Is it really
Immunologically
innert phase?

21. Charts indicate the percentage of T cells able to produce single,double, or triple Th1
cytokines (IFN-g, TNF-a, and IL-2) in the indicated categories of patients with CHB.
KENNEDY ET AL, 2012 GASTROENTEROLOGY Vol. 143, No. 3
CONCLUSIONS:
HBV infection in younger patients is not associated with an immune profile of
T-cell tolerance. On the contrary, children and young adults with chronic HBV
infection have an HBV-specific immune profile that is less compromised than
that observed in older patients.

22. Detailed analysis of the phenotype of T cells in these
patients showed that young IT patients with CHB
have a partially exhausted T cell profile, compared to
adult patients with a more exhausted T cell profile
(CD8+ T cells that are PD-1+ and CD127lo).
This could explain why older patients have a less
favorable response to therapy, and suggest that
earlier therapeutic intervention may be more
advantageous in young people who lack a fully
exhausted T cell profile.

23. Based on these findings and other reports ( Bertoletti and colleagues ,2015)
the IT phase is neither disease free “nor is it associated with an immune
profile of T-cell tolerance”

24. A Bertoletti and PT Kennedy ,2015
Kgatle, and Setshedi, 2016
 The capacities of the immune system is a dynamic
process that change with the patient age and so the
different squele of acute infection reflect the different
capacities of the immune system at different ages.
 The immune system is not always protective , several HBV
antigens & mechanisms can stimulate certain inhibitory
receptors of cytotoxic T-lymphocytes paving the way to liberal
viral replication.

25. 1st hypothesis

26. The different squele of acute infection reflect the different capacities of the
immune system at different ages.
• The development of chronic hepatitis B (CHB)
is inextricably linked to the patient’s age at the
time of infection:

27. Physiologically , the immune responses are not
identical during the life of an individual
The production of anti-inflammatory
cytokines (e.g., IL-10) is high in preterm infants, then progressively
declines over the first years of life, but is superior in children when
compared to adults.
Conversely, pro-inflammatory cytokines (e.g., IL-1beta, TNF-alpha) steadily
increase during early life40 until they reach the state of chronic low grade
systemic inflammation called ‘inflammaging’ that is characteristic of elderly
subjects.41
A Bertoletti and PT Kennedy ,2015

28. Interestingly, a detailed, albeit small, longitudinal study
has shown that more dramatic changes in serum ALT
levels occur in CHB patients around the 20- to 25-year-
old .
This is exactly the period where more pronounced pro
inflammatory events are observed in humans.
So the following ALTERNATIVE HYPOTHESIS has been
suggested :

29. Conventional (a) and proposed new representations (b) of the immunological events
occurring during the natural history of HBV infection.

30. 2nd hypothesis
 The immune system is not always protective , several HBV
antigens & mechanisms can stimulate certain inhibitory
receptors of cytotoxic T-lymphocytes paving the way to liberal
viral replication.

31. Impairment of T cell responses through stimulation of inhibitory cell receptors.
NTCP: sodium taurocholate cotransporting polypeptide Lag-3: lymphocyte activation gene
3; CTLA-4: cytotoxic T lymphocyte antigen 4; TIM-3: T cell immunoglobulin domain and
mucin domain 3; PD-1: programmed cell death 1; TIGIT: T cell immunoreceptor with Ig and
ITIM domains.
So
Blockade of the inhibitory
receptors by specific
antibodies restores T cell
differentiation and
cytokine production
leading to resolved HBV
infection with minimal
liver damage.
These may provide
novel immunotherapeutic
targets to eradicate
CHB infection while
minimizing the risk of
HCC progression..
HBV-mediated
abnormal
regulation of
lymphocyte
activation
The effect on inhibitory receptors is associated with increased viral replication and aggressive liver disease

33. Is it really a
histologically
benign phase?

35. (A) Percentage of HBcAg positive
hepatocytes (left) and HBsAg-positive hepatocytes (right) in each group;
IT (open circles), HBeAg(+) IA (open
squares), and HBeAg(-) IA (open triangles) are shown.

36. (B) Immunostaining identifying HBcAg-positive hepatocytes
(brown) and HBsAg-positive hepatocytes (pink) from
representative patients from each patient group

37. C) Ishak Fibrosis stage (left) and collagen proportionate area (right) of patients
studied in each phase of CHB .

38. (F) Identification of the inflammatory infiltrate as
from representative patients in each phase of CHB.

39. (E) Histologic activity
index scores (from left to right: interface hepatitis, confluent necrosis score, focal lytic
necrosis, apoptosis and focal inflammation
score, and portal inflammation score) of patients studied in each phase of CHB

41. In addition :
 This study confirms the presence of HBV-specific T-cell
responses and the significant extent of HBV-DNA integration/
cell mutagenesis along with clonal hepatocyte expansion
in the HRLI phase and across the disease phases.
 These findings further challenge the notion of an IT phase devoid of disease
progression, raising questions about the timing of
therapeutic intervention to minimize genetic damage to the
hepatocyte population and reduce the promotional role in
carcinogenesis of increased hepatocyte turnover.
 Because the risk of HCC already may be present in the HRLI phase
these data make a compelling case to consider antiviral therapy in these
patients.
( Mason et al., 2016).

42. Danger Lurks

44. ‘Immune tolerance’ in HBV infection:
danger lurks
Wai-Kay Seto and Man-Fung Yuen Published online 14 Sep 2016
NATURE REVIEWS | GASTROENTEROLOGY & HEPATOLOGY
On the basis of the results of this study , the immune
tolerant phase of CHB is no longer considered to be
quiescent, as liver histology, T-cell responses, viral
integration and hepatocyte clonality all point to
underlying disease activity .
In fact, the word “tolerance” is misleading, with the
term “high-replicative low-inflammatory” (HRLI),
suggested by the authors, being more appropriate.
On their excellent comment on MASON etal.,

45. ‘Immune tolerance’ in HBV
infection: danger lurks
Wai-Kay Seto and Man-Fung YuenTo
Although future
clinical studies are needed to evaluate if earlier
treatment brings about improved clinical outcomes,
the message from Mason et al. ,is clear:
in CHB patients considered immune tolerant,
underlying danger lurks.

47. Parameter
HBeAg Positive HBeAg Negative
Resolved HBV
Infection
Chronic
Infection
Chronic
Hepatitis
Chronic
Infection
Chronic
Hepatitis
HBsAg High
High/
intermediate
Low Intermediate Negative
HBeAg Positive Positive Negative Negative Negative
HBV DNA > 107 IU/mL
104 to 107
IU/mL
< 2000 IU/mL* > 2000 IU/mL Undetectable‡
ALT Normal Elevated Normal Elevated† Normal
Liver
disease
None/minimal
Moderate/sev
ere
None
Moderate/sev
ere
None§
Older term
Immune
tolerant
Immune
reactive
HBeAg positive
Inactive
carrier
HBeAg
negative
chronic
hepatitis
HBsAg
negative, anti-
HBc positive
Natural History of HBV:
New Nomenclature From EASL
Slide credit: clinicaloptions.com
EASL. J Hepatol. 2017;67:370.

49. Arguments Favoring Treatment of Immune-Tolerant CHB
• Good prognosis in the short or intermediate term does
not ensure good long-term outlook
• Reasons to fear that ongoing high-level viremia can be
oncogenic
• Marked viral suppression, even if not complete, can be
achieved in nearly all patients
• Transition to immune-active phase may go
unrecognized
• Some patients with normal ALT do have fibrosis
• Risk of transmission in viremic patients, especially
younger patients
Slide credit: clinicaloptions.com

50. Clinical Trials

53. These encouraging studies from the UK and
India contrast with 2 more recent multicenter
trials performed by the Hepatitis B Research
Network in the United States and Canada.

54. • Conclusion: A lead-in strategy of 8 weeks of
entecavir followed by combination peginterferon
and entecavir therapy for 40 weeks had limited
efficacy in adults in the IT phase of chronic HBV
infection and cannot be recommended.
(Hepatology2019;69:2338-2348).

55. Conclusion: The combination of entecavir and peginterferon
for up to 48 weeks rarely led to loss of HBeAg with sustained
suppression of HBV DNA levels in children in the immune-
tolerant phase of HBV infection, and treatment was associated
with frequent AEs. (Hepatology 2019;69:2326-2337)

56. SO, Although HBV DNA levels are highest in the immune
tolerant phase, current guidelines do not recommend
treatment for patients in this phase because the
likelihood of treatment-induced HBeAg
loss is extremely low.

57. Recognizing that persistently high HBV DNA
levels and having a family history of HCC
increase the risk of HCC, guidelines recommend
treatment if patients remain in the immune
tolerant phase after the age of 30 to 40 years or
if there is a family history of HCC.

58.  The AASLD guidelines used age 40
as the cutoff based on data from a study showing the
risk of cirrhosis development increased from 1.1%
to 4.1% to 28% in patients who lost HBeAg before
age 30, between 30 and 39, and after age 40, respectively.
Chu CM&Liaw YF.2007
 By contrast, the EASL guidelines selected
age 30 as the cutoff. It is unclear which cutoff is more
appropriate.
 Many experts have advocated for treatment
early in the course of infection to minimize liver
injury, integration of HBV DNA, and risk of HCC.

59. Terrault. Hepatology. 2018;67:1560. www.aasld.org. Slide credit: clinicaloptions.c
• AASLD recommendations for antiviral therapy
– Adults with immune‐active CHB (HBeAg negative or
HBeAg positive) to decrease the risk of liver‐related complications
• Additional factors: age, family history of HCC or cirrhosis, previous
treatment history, presence of extrahepatic manifestations, presence of
cirrhosis
– Select group of immune-tolerant adults older than 40
yrs of age with normal ALT and elevated HBV DNA (1,000,000 IU/mL)
and liver biopsy specimen showing significant necroinflammation or
fibrosis.
If treatment is not indicated, actively monitor
as candidacy may change with disease progression

60. Another group of patients in the immune tolerant phase for which antiviral
treatment is recommended are :
 women with high viremia (>200,000 IU/mL).(13) Several studies showed that
administration of antiviral therapy to these mothers in the third trimester of
pregnancy further reduced the risk of mother-to-child transmission
in newborns .
 Antiviral therapy is also recommended as prophylaxis
for patients who are HBsAg-positive as well as
patients who are HBsAg-negative and hepatitis B core
antibody-positive who require treatment with immunosuppressive
therapies that are predicted to have
a moderate to high risk of HBV reactivation.(
Anna Suk-Fong Lok, Hepatology Communications, VOL. 3, NO. 1, 2019

61. 2017 EASL Guidelines: Criteria for Treatment of CHB
EASL. J Hepatol. 2017;67:370. Slide credit: clinicaloptions.com
Standard Indications
HBV DNA, IU/mL ALT Liver Disease
> 2000 > ULN* Moderate necroinflammation or fibrosis
Any Any Cirrhosis
> 20,000 > 2 x ULN* Any
*ULN ~40 IU/L.
Other Indications, Even if Standard Indications Are Not Met
CHB and family history of HCC or cirrhosis with extrahepatic manifestations
HBeAg positive, high HBV DNA, persistently normal ALT, and aged > 30 yrs
+
+
+
+
+
+
If treatment is not indicated, actively monitor
as candidacy may change with disease progression

62. To Summarize
• Immune tolerance is a misnomer , yet it is still
hard to treat.
• We must no longer simply “tolerate” the adult in
the IT phase, but rather actively manage risk
factors that promote fibrosis and HCC, such as
alcohol use or fatty liver, and serially track
changes in the IT profile that signal phase
transition to more active disease and keep low
threshold to initiate antiviral therapy untill
further recommendations approved.

63. Thank You