SummaryThe aetiology of vitiligo remains obscure. In this study, the role of integrins in the observed inability of melanocytes to repopulate lesional skin was investigated. Antibodies directed to a 2 , a 3 , a 5 , a v , a 6 , b 1 and b 3 integrin subunits were used. Immunohistology revealed no marked differences in the overall levels of expression of integrins between control, non-lesional, perilesional or lesional skin. Moreover, no differences were noted in the level of expression of integrins or the adhesive capacity between cultured control cells derived from three separate donors and vitiligo-derived melanocytes from two donors. Rather, it was clearly observed that towards the lesion, vitiligo skin contains increasing amounts of tenascin in the basal membrane and papillary dermis in five patients employing T2H5 antihuman tenascin antibody. The anti-adhesive effect observed in vitro for this extracellular matrix molecule using normal melanocytes may contribute to loss of pigment cells in vitiligo or to ineffective repopulation of the lesions.In vitiligo, melanocytes are gradually lost in depigmenting lesions of the skin. 1 It has been suggested that defective adhesion is involved in loss of melanocytes in this pigmentary disorder. 2 Moreover, the persistence of depigmented lesions is suggestive of defective melanocyte migration which may be reversed by photochemotherapy, 2 and therefore baseline expression of adhesion molecules may differ in vitiligo as compared with control skin. Melanocyte adhesion, spreading and migration is mediated by integrins. 3 Employing antibodies to integrin subunits, the specific integrins involved in each process have been identified in vitro. 3,4 Importantly, all integrins thus far identified on melanocytes can also be found on neighbouring keratinocytes. Although immunohistology has been employed to identify integrins expressed on melanocytes in situ per se, 3 this may not be the method of choice to determine differences in the level of expression by melanocytes. Even by double immunostaining procedures, it is difficult to distinguish between integrin expression by melanocytes vs. neighbouring keratinocytes. Therefore, in vitro cultures derived from control as well as from vitiligo non-lesional skin were employed to investigate further potential differences in adhesive behaviour in vitiligo and control skin. In addition, the use of cultured cells provides the opportunity to perform functional adhesion assays. In this respect it is of great interest to note that cultured melanocytes from nonlesional vitiligo skin appear to retain disease-related characteristics. It has been demonstrated that vitiligo melanocytes have altered growth characteristics under limiting conditions. 5 Moreover, upon electron microscopic observation, dilated rough endoplasmic reticulum (RER) is apparent in diseased cells from human and mouse vitiligo subjects. 6,7 Therefore, the use of cultured cells to investigate differences in adhesive characteristics is justified.The level of expression of relevant i...