S100A8 and acquired polycythemia vera: Comparison of gene expression profiles from multiple inflammatory skin diseases revealed that pustular psoriasis samples clustered in the vicinity of PV based on a common Th17 signature (IL17A/C, S100A8/A9, IL36G/A/RN, DEFB4A, DEFB103B), but also identified an additional autoinflammation signature with expression of IL-1 family cytokines IL1A and IL1B and neutrophil-recruiting chemokines CXCL1 and CXCL8 (Fig. 3 A).