Biomolecular index of therapeutic efficacy in psoriasis treated with anti-TNF-α agents

Clinical or quality of life assessments are currently available for psoriasis severity evaluation and therapeutic response. Laboratory scores focused to measure and follow treatment efficacy are lacking at present.A microscopic and biomolecular score was designed to monitor skin disease severity and clinical response to anti-psoriatic treatments. A susceptibility gene analysis on cellular retinoic acid binding protein-II (CRABP-II), acting on keratinocyte differentiation, was also performed. A Molecular Index of Therapeutic Efficacy (MITE) was defined by assembling morphometric/semiquantitative measurement of epidermal thickness, immunohistochemical Ki-67, keratin 17 and CRABP-II expression of lesional and non-lesional psoriatic skin biopsies before and after anti-tumor necrosis factor (TNF) α therapies. A 0-12 MITE score was correlated with Psoriasis Area and Severity Index (PASI) and Psoriasis Disability Index (PDI) scores and inflammation. Three CRABP-II SNPs were analyzed by TaqMan assay.All parameters were highly expressed in psoriatic lesions and reduced after 12 weeks of anti-TNF-α treatments. MITE score strongly correlated with PASI and PDI values either before or after therapies (P<0.001 and P<0.001, respectively). Conversely, MITE values did not change after treatments of non-responder patients. CRABP-II did not result in a psoriatic susceptibility gene for the SNPs probes analyzed.MITE score variations corresponded to the patients' clinical improvement following anti-TNF-α treatments, with significant statistical correlation among MITE, PASI and PDI scores. If confirmed in a larger series and/or in different hyperproliferative and inflammatory dermatoses, MITE score could be proposed as additional monitoring system to evaluate treatment protocols in skin disorders and targeted biomolecular pathways supporting clinical efficacy.