IGF1 and keratoconus: In order to assess whether IGFBP2 released by psoriatic keratinocytes was functionally active, and hence able to bind and regulate IGF-1 binding to its receptors on cell surface, we collected sups from unstimulated cultures of psoriatic keratinocytes (pso KC, IGFBP2 concentration: 10.06 ± 1.20 ng/ml) and from healthy cells (IGFBP2 concentration: 0.06 ± 0.01 ng/ml).