CD1A and leprosy: To obtain more knowledge of the role of epidermal LCs in the immune response to Mycobacterium leprae, the causative agent of leprosy, and the pathogenic mechanisms underlying M. leprae-induced immune responses in both types of leprosy reactions, a quantitative analysis of epidermal and dermal CD1a expression in the biopsy specimens of cutaneous leprosy lesions was performed using immunohistochemistry.