Recently, McCord et al. reported that PB125, a CA-based therapeutic agent, was potentially useful in the treatment of respiratory viral diseases, including COVID-19, in part by inhibiting cytokine storm
[25][26][27]. They observed a marked downregulation of genes encoding inflammatory cytokines including IL-1β, IL-6, TNF-α, cell adhesion molecules (ICAM-1, VCAM-1, and E-selectin), and a group of interferon-γ-induced genes, suggesting that cytokine storm might be suppressed by CA
[25][26][27]. McCord and colleagues further reported that PB125 downregulates ACE2 and TMPRSS2 mRNA expression in human liver-derived HepG2 cells, consistent with the notion that CA might inhibit viral entry, which ACE2 and TMPRSS2 proteins mediate
[25][26][27]. These results suggest that the use of rosemary extract or CA might represent a possible therapeutic against acute ARDS in the lung and more protracted cytokine production
[25][26][27]. Therefore, clinical testing of rosemary extract or CA for either acute COVID-19 lung disease or chronic (so-called long) COVID-19 might be considered. The rationale for such treatment is discussed further below. A caveat with these findings, however, is the fact that IL-1 or IL-6 inhibitors have been reported to suppress SARS-CoV-2 neutralizing antibodies in patients with COVID-19
[28]. Hence, the timing of any therapy aimed at suppressing these cytokines will have to be judiciously monitored in order not to interfere with anti-SARS-CoV-2 antibody therapies
[25].