Lichen striatus versus linear lichen planus: a comparison of clinicopathological features, immunoprofile of infiltrated cells, and epidermal proliferation and differentiation.

BACKGROUND: Lichen striatus (LS) and linear lichen planus (LLP) are separate uncommon disorders belonging to linear inflammatory dermatoses. The immunotyping of inflammatory cells has been investigated in LS and lichen planus (LP), but epidermal proliferation and differentiation have little been described in LS and LLP.

METHODS: The clinical and pathological data of eight patients with LS and seven with LLP were retrospectively collected. Immunotyping of infiltrated cells and expression of Ki-67, K16, involucrin, and filaggrin were stained by immunohistochemistry in skin lesions of these patients and normal skin of eight healthy controls.

RESULTS: Dermal infiltrates contained primarily CD3+ and CD68+ cells in three groups. CD4+ cells were predominantly located in the perivascular area, while CD8+ cells were frequently close to the junctional zone. Compared with control skin, epidermal and dermal CD1a+ cells, and dermal CD3+, CD4+, CD8+, and CD68+ cells were increased in LS and LLP (P < 0.05), while Ki-67+ cells were significantly high in LLP (P < 0.05) but not in LS. K16 and involucrin expression in LLP were more extensive than in LS, and filaggrin expression was similar between both entities.

CONCLUSIONS: Our results indicate that the predominance of CD8+ cells and increased epidermal proliferation and abnormal keratinization are present in both dermatoses, although the levels of the above indexes are mild in LS as compared to LLP. These two entities might be due to the interaction of infiltrated cells and keratinocytes, and CD8+ cells could play a pivotal role in their pathogenesis.