1.
Eosinophil responses during COVID-19
infections and coronavirus vaccination
dr. Rentha Monica S
dr. Ari Baskoro SpPD, K-AI

2.
The Topics
Eosinophil responses during respiratory track infection
Eosinophil responses in Covid 19
Vaccine induced immunopathology linked to coronavirus
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3.
The Eosinophil: A Versatile Cell
● Eosinophils are polymorphonuclear leukocytes with a bilobed
nucleus
● Eosinophil have potent antiinflammatory effects in a
number of disease.
● Recently eosinophil have shown have another functions; which
are immunoregulation and antiviral activity.

4.
EOSINOPHIL RESPONSES
DURING RESPIRATORY
VIRUS INFECTIONS

5.
Mechanisms for Viral Recognition and
Clearance by Eosinophils
Recognition of virus by eosinophil receptors
TLR in eosinophils >>>> neutrophils
RIG-1 receptor >> recognizes RNA sequences although
expression of this receptor is lower in eosinophils than in
neutrophils,
HMGB1 receptor >> Eosinophils are able to recognize viral
particles and products of cell necrosis

6.
Mechanisms for Viral Recognition and
Clearance by Eosinophils
Role of eosinophils in antigen presentation
Eosinophil are able to migrate from the bronchial lumen to the
paratracheal draining lymph nodes or thoracic lymph nodes to stimulate
proliferation of CD4+ T cells by antigen presentation.

7.
Mechanisms for Viral Recognition and
Clearance by Eosinophils
Antiviral action of activated eosinophils in the immune response
1. ECP and EDN >> antiparasitic, antibacterial molecules, antiviral.
Both EDN and ECP have been shown to destroy the extracellular virions
of RSV group B suspensions, and EDN has even been reported to have
an effect against hepatitis B virus.

8.
Mechanisms for Viral Recognition and
Clearance by Eosinophils
Antiviral action of activated eosinophils in the immune response
2. Secretion of a massive array of molecules, such as IFN regulatory
factor 7, NOS-2, IFN-β, ribonucleases (eg, EAR-1 and EAR-2), and
interleukins and chemokines (eg, IL-6, IP10, CCL2, and CCL3), all of
which have variable effects on viral clearance

9.
Mechanisms for Viral Recognition and
Clearance by Eosinophils
Antiviral action of activated eosinophils in the immune response
3. Eosinophils are able to catapult their mitochondrial DNA without
dying. The DNA then forms extracellular structures capable of trapping
and killing bacteria.
4. Eosinophils are able to release typical antiviral type 1 cytokines such
as IFN-γ, IL-2, and IL-12 stored inside their granules in response to
stimuli such as TNF-α, IFN-γ, and IL-10

10.
EOSINOPHIL RESPONSE
IN COVID-19

11.
Early observations in COVID-19 patients reported eosinopenia (low
blood eosinophil count) in hospitalized patients, and, more importantly, it
seems that this observation correlated with the severity of the disease or
with a poor prognosis
Importantly, eosinophil levels improved in patients before discharge,
suggesting that increased eosinophil counts may indicate an
improvement in a patient’s clinical condition

12.
The immune mechanism of eosinopenia in COVID-19 remains
unclear, although it is likely multifactorial
Inhibition of the main steps in the eosinophil life cycle (ontogeny, rolling,
adhesion, and migration)
apoptosis induced by type 1 IFN during acute infection
association with eosinophil consumption by eosinophil antiviral actions
Thus, Jesenak et al considered that eosinopenia could be either the sign
or the symptom of host exhaustion due to clearance of COVID-19 virus.

13.
Eosinophil responses related to Covid 19
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14.
VACCINE-INDUCED
IMMUNOPATHOLOGY
LINKED TO CORONAVIRUSES

15.
Eosinophil- associated disease enhancement following
exposure after vaccination is unfortunately not a new
phenomenon.
The development of a safe and efficacious SARS-
CoV-2 vaccine will require the development of vaccine
candidates that take into account the risk of similar
vaccine- associated immunopathology.

16.
Conclusion
● Experimental evidence that eosinophils have potential antiviral activity
● There is little indication that eosinophil have a protective effect during SARS
cov 2 infection
● There is considerable concern about whether SARS-CoV-2 exposure
postvaccination would cause eosinophil-associated lung pathology through
immunopotentiation
● Although the ongoing COVID-19 outbreak places new emphasis on the critical
need for an effective SARS-CoV-2 vaccine, safety must be a central focus for
any vaccine designed for general use.

17.
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