GZMB and infection: Thus, in the extracellular milieu, GrB plays an important role in the loss of tissue function and integrity in the response to infection (Choy et al., 2004; Tschopp et al., 2006; Granville, 2010; Hendel et al., 2010; Russo et al., 2018; Turner et al., 2019; Matsubara et al., 2020), with high levels of GrB in bronchoalveolar lavage fluid that correlate with disease severity (Rasmuson et al., 2016).