PPIB and scleroderma: More specifically, IR-induced Survivin foci clearly co-localized with centromeric heterochromatin labelled with CREST serum in different cell lines, most prominently after high-dose IR (Figure 2C,D and Figure S3B) CREST autoimmune sera are derived from scleroderma patients and directed against human centromere proteins, mainly CENP-A, -B, and -C in varying stoichiometries [26].