For example, Shu et al. in their clinical trial, performed on 41 COVID-19 patients which 12 of whom received 2 × \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${10}^{6}$$\end{document}106 UC-MSCs, for one time, found that cells could potentially reduce the serum IL-6 and CRP levels and improve CT scan images over a 28-day follow-up period [39]. Here, IL6 is linked to COVID-19.