Merkel cell number and distribution, and CD200 expression in patients with lichen planopilaris and discoid lupus erythematosus.

BACKGROUND

Immune mechanisms are considered to be responsible for the pathogenesis of cicatricial alopecia in lichen planopilaris (LPP) and discoid lupus erythematosus (DLE) diseases. CD200 has an immunomodulatory function in hair follicles. The functions of Merkel cells (MCs) in hair follicles remain to be fully understood.

OBJECTIVE

This study aimed to determine the number and distribution of MCs as well as CD200 expression in patients with DLE and LPP.

METHODS

Using immunohistochemistry, the number and distribution of MCs (staining with CK20) and CD200 expression in biopsy specimens of LPP and DLE patients were compared with control group patients.

RESULTS

The number of follicular MCs, total MCs, mean follicular MCs, and CD200 expression were significantly lower in the case groups compared to the control group. In CD200- cases, the number of follicular MCs and mean follicular MCs were significantly lower than in CD200+ cases. Retrospective design, lack of data regarding the history of alopecia in the control group, and unknown stage of disease in patients were the limitations.

CONCLUSION

MC loss might play a role in immune privilege collapse in hair follicles. This study is novel in terms of investigating MCs in DLE and LPP patients.