Lichen sclerosus: evidence that immunological changes occur at all levels of the skin

An immunohistochemical approach was used to characterize the inflammatory i nfiltrate in vulval lichen sclerosus, using monoclonal antibodies to CD3, C D4, CD8, CD68 and HLA-DR. Significant numbers of CD4+ and CD8+ lymphocytes were observed in the dermal band of inflammatory cells in approximately equ al proportions. Less numerous CD4 + and CD8 + lymphocytes also occurred adj acent to the dermoepidermal junction and occasionally in the lower epidermi s. Increased numbers of cells staining with the monocyte/macrophage marker CD68 were also present in the band of inflammatory cells as well as being s cattered diffusely throughout the sclerotic region. Expression of HLA-DR in the lichen sclerosus specimens was increased within the inflammatory infil trate and around blood vessels in the dermis. All the vulval lichen scleros us specimens also demonstrated some HLA-DR expression around the keratinocy tes, suggesting that these keratinocytes might be involved in antigen prese ntation. We also studied the expression of CD44 and its isoforms 3G5 (marke r of V3), 8G5 (marker of V6), 3D2 (marker of V4/5) and IE8 (marker of V8/9) . CD44 has been proposed to play a part in lymphocyte homing, cell-matrix i nteraction (particularly with hyaluronic acid), lymphocyte activation and m alignant progression of certain tumours. The epidermis of the lichen sclero sus specimens appeared to demonstrate a greater intensity of staining with the pan-CD44 marker F10-44, and reduced staining with 3G5, 3D2 and IE8 comp ared with normal skin. Like normal skin, the dermis of the lichen sclerosus specimens did not demonstrate staining with 3G5, 3D2, 8G5 or 1E8, but did show staining with F10-44. However, the pattern of the dermal staining with F10-44 reflected the position of the inflammatory infiltrate and was spars e in the five sections where there was a prominent sclerotic zone, but incr eased in the three sections where there was a prominent band of inflammatio n cells. Our results demonstrate evidence of immunological changes at all l evels of skin involved by lichen sclerosus, including the epidermis.