CD44 and hyaluronate expression in follicular mucinosis.

BACKGROUND: CD44 is a membrane glycoprotein and the major cell-surface receptor of hyaluronate (HA). Lack of CD44 expression in mouse epidermis leads to an abnormal HA accumulation in the dermis, indicating an important role of CD44 in local HA metabolism. Decrease of epidermal CD44 expression in patients of lichen sclerosus et atrophicus is potentially responsible for dermal deposition of HA in this disease. Stromal HA accumulation is associated with decreased or lost expression of CD44 in perifollicular solitary cutaneous myxoma, myxoid dermatofibroma, and dermatofibrosarcoma protuberans.

METHODS: We examined the expression of CD44 and HA in the skin biopsy specimens of 10 patients with follicular mucinosis by using CD44-specific antibodies and biotinylated HA-binding protein (HABP), respectively.

RESULTS: No difference of CD44 expression was observed in the follicular keratinocytes when compared with those of unaffected interfollicular epidermis. The follicular zones of mucin deposition were strongly positive for HA. A weak interkeratinocyte staining for HA was also observed in the interfollicular epidermis. However, HABP staining revealed a stronger reactivity in the follicular keratinocytes surrounding the mucin-accumulated areas compared to the interfollicular keratinocytes.

CONCLUSION: Our results suggest an active secretion of HA by follicular cells in follicular mucinosis.