Indirect immunofluorescence of oral lichen planus.

Sections of lesional tissue from 6 patients who exhibited only oral lesions of lichen planus (LP) were incubated with autologous serum and studied immunopathologically for the presence of lichen planus specific antigen (LPSA). None of the specimens was positive for LPSA. Serum from the oral LP patients was subsequently incubated with allogeneic cutaneous LP lesional tissue sections, which resulted in the demonstration of LPSA in 2 of the 4 sera examined. These results suggest an immunologic relationship between cutaneous LP and at least some cases of oral LP.