EXPRESSION OF INTEGRINS IN HUMAN NAIL MATRIX

The aim of this study was to characterize cell-cell and cell-matrix in teraction by evaluating the expression of different integrins in the n ail matrix. Nail biopsies were obtained from two cadaver fingers, and eight patients with ingrowing toenails. Frozen sections were stained b y indirect immunofluorescence using anti-alpha 1, anti-alpha 2, anti-a lpha 3, anti-alpha 4, anti-alpha 5, anti-alpha 6, anti-alpha v, anti-b eta 1, anti-beta 4 and anti-ICAM-1 monoclonal antibodies. Biopsies fro m normal human foreskin were evaluated as controls. alpha 1, alpha 4 a nd alpha 5 subunits were absent from both nail matrix and normal human skin, alpha 2, alpha 3 and beta 1 subunits were expressed in the basa l and suprabasal layers of nail matrix, but only in the basal layer of skin epidermis. alpha 6 and beta 4 subunits were strongly expressed i n the basement membrane zone and in the basal layer of both nail matri x and epidermis. The av subunit was expressed in the basal layer of na il matrix. ICAM-1 was not expressed in nail matrix epidermis. Our find ings show that despite the distinctive features of the nail apparatus, compared with the epidermis, the pattern of integrin expression is si milar, although some differences in the distribution of alpha 2, alpha 3 and beta 1 subunits are detectable. These are probably related to t he peculiar differentiation and keratinization of the nail.