MMP9 and COVID-19: As reprograming of neutrophils could contribute to ECM fluctuations in COVID‐19, we explored this hypothesis by correlating MMP‐2, MMP‐3, MMP‐7 and MMP‐9 with the numbers of neutrophils and NCF2 expression in a four‐variable analytic setting (Figure 3B), and with the number lymphocytes vs. NCF2 (Figure 3C).