Skin biopsy specimens from six patients with lichen nitidus (LN) were negative for γ-globulin when stained with fluorescein-labeled antihuman immunoglobulins. In only two papillae of one unusual lesion were small fluorescent bodies seen. Immunoglobulins at the epidermal-dermal interface are present in over 95% of lichen planus (LP) lesions and were present in the concomitant lesions of LP and Koebner's reaction in one of the six patients; four patients, including the one with immunoglobulin deposits in one papilla, had only LN. Although LP and LN can occur simultaneously, they are clinically and histologically distinct, and immuofluorescent findings do not substantiate a relationship between the two diseases.
Waisman M, Dundon BC, Michel B. Immunofluorescent Studies in Lichen Nitidus. Arch Dermatol. 1973;107(2):200-203. doi:10.1001/archderm.1973.01620170012002