IGFBP4 and type 1 diabetes mellitus: Notably, there were no differences in expression of any genes previously implicated in β cell senescence (14, 16), such as cyclin-dependent kinase inhibitor genes CDKN1A, CDKN2A, SASP genes IL6, CXCL1, IGFBP4 or BCL-2 family prosurvival genes BCL2, BCL2L1, and BCL2L2 in α cells of T1D donors relative to ND donors (Figure 4A).