Immunofluorescence abnormalities in lichen planopilaris

Lichen planopilaris is believed to be a variant of lichen planus because both diseases have similar histologic features. However, as the clinical features of the two diseases differ, we conducted immunofluorescence studies to examine the relation between the two conditions more closely.

Direct immunofluorescence was performed on scalp lesions of seven patients with lichen planopilaris. All had abnormal linear deposits of Ig restricted to the basement membrane zone of hair follicles. The deposits consisted of only IgG or IgA in five patients (70%) and of IgG in combination with other Igs in two patients (30%). Basement membrane zone deposits of fibrin were present in only one patient (14%) and were linear in appearance. There was no staining of ovoid bodies. These immunofluorescence abnormalities differ from those associated with lichen planus where basement membrane zone deposits of fibrin are present in almost all patients, where the basement membrane zone deposits are fibrillar in appearance, and where the deposits of Ig over ovoid bodies are common.

The different appearance and composition of abnormal deposits of immunoreactants in lichen planopilaris and lichen planus suggest that the two conditions are different diseases.