PF4 and depressive disorder: The mRNA expression profile associated with Any Depression (AD) included four genes, three of them (PDGFA, PF4, and TGF-β1) were down-regulated (P-values: <0.0054, <0.0123 and <0.0152; respectively), while the STAT4 gene was up-regulated (P-value <0.0396) (Table 2).