ADAM10 and psoriasis: The second generation retinoid acitretin, which is in clinical use to treat psoriasis, mildly increases ADAM10 levels in vitro by 1.3‐fold (Tippmann et al, 2009) and sAPPα levels in human CSF by 25% (Endres et al, 2014) and, thus, was expected to also increase CSF levels of the cleaved ectodomain of other ADAM10 substrates in the brain.