Biomolecular index of therapeutic efficacy in psoriasis treated by anti-TNF alpha agents.

BACKGROUND: 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. METHODS: Design a microscopic and biomolecular score 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, keratin17 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)/Psoriasis Disability Index (PDI) scores and inflammation. Three CRABP- II SNPs were analyzed by TaqMan assay. RESULTS: All parameters were highly expressed in psoriatic lesions and reduced after 12 weeks of anti-TNFα 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 resulted a psoriatic susceptibility gene for the SNPs probes analyzed. CONCLUSIONS: MITE score variations corresponded to the patients' clinical improvement following anti-TNFα 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.