PRF1 and type 1 diabetes mellitus: Analysis of the proportion of perforin- and granzyme B-positive granules and the evaluation of perforin and granzyme potential in CD16+ and CD56+ NK cells revealed an increased perforin potential in CD56+ NK cells in T2D compared to both healthy donors (p = 0.0031) and T1D (p = 0.0031), Table 4, Figures 3C, D.