RNA of SARS-CoV-2 receptors but no virus in COVID-MDR lesional
skin
The distinct cellular and molecular signature in COVID-MDR suggested
that COVID-19 may impact this reaction in the skin. A SARS-CoV-2 PCR on
RNA turned out negative for all COVID-MDR skin samples. We then
investigated the expression of the known SARS-CoV-2 receptors ACE2,
Transmembrane protease, serine 2 (TMPRSS2), BSG (Basigin; CD147), and
DPP4 (Dipeptidyl peptidase-4,
CD26)27-29. We did not
find any difference in keratinocyte ACE2 expression between COVID-MDR,
DRESS and MDR on a protein level by IHC staining (Figure S2). On the
gene expression level however, ACE2 and DPP4 but not other
receptor-related molecules were upregulated in COVID MDR compared to HC
(Figure 4D, S4).