Of note, the disruption in PNN formation during infection was associated with increased expression of MMP-12 and -19 but not MMP-9 or ADAMTS-4 or -5, which have been previously shown to be increased in some disorders where established PNNs are disrupted (Roughley and Mort, 2014; Carceller et al., 2020). This evidence concerns the gene ADAMTS4 and infection.