- Psoriasis lesions are rich in IL-17–producing T cells as well as neutrophils, which release webs of DNA-protein complexes known as neutrophil extracellular traps (NETs). Because we and others have observed increased NETosis in psoriatic lesions, we hypothesized that NETs contribute to increased T helper type 17 (Th17) cells in psoriasis. After stimulating peripheral blood mononuclear cells with anti-CD3/CD28 beads for 7 days, we found significantly higher percentages of CD3+CD4+IL-17+ (Th17) cells in the presence versus absence of NETs, as assessed by flow cytometry, IL-17 ELISA, and IL17A/F and RORC mRNAs.
- Mild versus severe psoriasis is often distinguished by clinical measures such as the extent of skin involvement or Psoriasis Area and Severity Index score, both of which use arbitrary boundaries. It is widely assumed that severe psoriasis involves higher levels of skin inflammation, but comparative molecular profiles of mild versus severe disease have not been performed. In this study, we used immunohistochemistry, reverse transcription PCR, and gene arrays to determine the phenotype of North American patients with mild psoriasis (n = 34, mean PASI score = 5.5) versus severe psoriasis (n = 23, mean PASI score = 23.2).