Angiotensin-converting Enzyme 2 (ACE2) Expression in Tonsils and Adenoids

The entry point for SARS-CoV-2 into the body is the nasal and pharyngeal mucosa.
Angiotensin-converting enzyme 2 (ACE 2) was quickly identified as the functional receptor for
SARS-CoV-2. Furthermore, the TMPRSS2 serine protease is required for the anchoring of the S
protein in cell lines. In addition, the most commonly used screening test is a test for viral
RNA by RT-PCR on a nasopharyngeal sample because the viral load is high.

The tonsils and adenoids could be a target organ of the virus. In order to study this
hypothesis, the expression of ACE 2 and the serine protease TMPRSS2 will be sought in these
tissues.

In addition, children, generally at high risk of severe viral respiratory infections (RSV,
influenza), have milder symptoms than older patients with SARS-CoV-2 infection. The reason
for this difference remains elusive. But one of the hypotheses formulated is that the level
of expression of ACE 2 and / or TMPRSS2 may differ between adults and children, the viral
load seeming to be correlated with the severity of the attack. In order to study this
hypothesis, we will therefore compare the level of expression of ACE 2 in the tonsil tissue
of children and adults.