Transcriptomic-associated clusters (TACs) are groups of genes that determine the endotype, or subcategory, of asthma. There are three TACs of asthma that differ based on their autoimmune response. They have the following phenotypes:

• TAC1: eosinophilic inflammation; high levels of T2
• TAC2: neutrophilic inflammation; presence of imflammasome activation
• TAC3: paucigranulocytic inflammation

ACE2, TMPRSS2, and Furin expression levels were determined from sputum samples from those who were asthmatic as well as healthy volunteer controls. These findings suggest that the mechanisms used by TAC1 and TAC2 may increase the expression of ACE2 and furin. Additionally, this shows that genetic differences may contribute to the severity of COVID-19 in those with asthma.