THE ROLE OF ALPHA-E-BETA-7 INTEGRIN (CD103) AND E-CADHERIN IN EPIDERMOTROPISM IN CUTANEOUS T-CELL LYMPHOMA

Adhesion molecules such as integrins and cadherins are thought to play a critical role in T-cell migration and localization within the epide rmis (epidermotropism). The purpose of this study was to correlate T-c ell expression of the integrin CD103 and E-cadherin in cutaneous T-cel l lymphoma (CTCL). Serial sections of skin biopsies from 22 patients w ith CTCL and 13 with benign reactive dermatitis were stained with anti bodies to CD4, CD103, and E-cadherin by the avidin-biotin peroxidase t echnique. CD103 was expressed on single epidermotropic CD4+ T-cells in 9/9 early stage (patch/plaque) CTCL and 6/10 reactive dermatitis biop sies. Less than 30% of dermal T-cells expressed CD103. All 4/4 late st age (tumor) CTCL were CD103-. Epidermal aggregates of CD4+ T-cells (Pa utrier's microabscesses) were CD103-. E-cadherin was expressed on epid ermal keratinocytes and follicular and sweat gland epithelia but not o n T-cells. We conclude that CD103 expression on cutaneous T-cells para llels the degree of epidermotropism exhibited in both neoplastic and i nflammatory disorders of the skin. E-cadherin is not expressed on T-ce lls infiltrating the skin. Further investigation is necessary to furth er elucidate the interaction between CD103 and E-cadherin in facilitat ing trafficking of T-cells into the epidermis.