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CD26/dipeptidyl‐peptidase IV in psoriatic skin: upregulation and topographical changes
Author(s) -
Van Lingen R.G.,
Van De Kerkhof P.C.M.,
Seyger M.M.B.,
De Jong E.M.G.J.,
Van Rens D.W.A.,
Poll M.K.P.,
Zeeuwen P.L.J.M.,
Van Erp P.E.J.
Publication year - 2008
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.2008.08515.x
Subject(s) - psoriasis , dipeptidyl peptidase , immunohistochemistry , downregulation and upregulation , dipeptidyl peptidase 4 , dermis , population , epidermis (zoology) , staining , biology , pathology , immunology , medicine , endocrinology , enzyme , biochemistry , anatomy , environmental health , diabetes mellitus , type 2 diabetes , gene
Summary Background Psoriasis is known to affect 2–3% of the population and can be considered an organ‐specific autoimmune disease. CD26/dipeptidyl‐peptidase IV (DPP‐IV) is a membrane‐bound protease with diverse properties. In theory, the expression of CD26/DPP‐IV has common grounds with three principal key players of the psoriatic pathogenesis: keratinocytes, T cells and cytokines. Objectives To assess CD26/DPP‐IV expression in psoriasis in order to expand on the search for complementary biomarkers related to inflammation and proliferation in psoriasis. Methods The pattern of expression of CD26/DPP‐IV was investigated on the mRNA‐, protein‐ and enzyme‐functionality level using immunohistochemical, immunofluorescent and enzyme activity labelling techniques. Results An 11‐fold significant increase of CD26/DPP‐IV on the mRNA level was demonstrated in psoriatic epidermal sheets compared with normal skin. Immunohistochemistry on psoriatic sections showed a distinct patchy honeycomb‐like CD26/DPP‐IV staining in the suprapapillary layers. Moreover, a clearly distinguishable column‐like staining pattern throughout the suprabasal compartment along the rete ridges was seen, whereas in normal skin these patterns were absent. Strikingly, CD26/DPP‐IV enzyme activity correlated with this immunohistochemical reactivity pattern for the CD26/DPP‐IV protein. The T‐cell bound expression of CD26/DPP‐IV in psoriatic skin was explicitly present, albeit in small quantities. Conclusions Our data provide clear evidence for a versatile upregulation of CD26/DPP‐IV expression in psoriatic (epi)dermis. Although the exact functional contribution remains speculative, the topographical distribution of this complex multifunctional protein suggests a suitable role as a complementary biomarker in psoriasis.