Cytotoxic molecule expression and epithelial cell apoptosis in oral and cutaneous lichen planus

We evaluated the expression of T cell–restricted
intracellular antigen (Tia-1), granzyme B, and perforin
by lymphocytes and the degree of epithelial apoptosis in
oral and cutaneous lichen planus (LP) in 51 untreated
cases, including 27 oral LP (OLP) and 24 cutaneous
LP (CLP) cases. The number of total dermal-positive
lymphocytes in OLP and CLP was similar, indicating
similar activity of the inflammatory process.
Intraepithelial Tia-1–positive, perforin-positive, and
granzyme B–positive lymphoid cells were more
numerous in OLP than in CLP (P < .05). The epithelial
cell apoptotic index (AI) was increased significantly in
OLP (P < .05), particularly in erosive-atrophic
variants. A linear correlation between AI and the mean
± SEM number of intraepithelial and dermal perforin+
cells (6.85 ± 2.44 and 27.48 ± 10.19, respectively), per
10 high-power fields for OLP and for CLP (1.17 ± 0.88
and 10.42 ± 5.74, respectively), was found
(intraepithelial, r = 0.50; dermal, r = 0.51; P < .01).
These data suggest a pivotal role for perforin in
triggering epithelial cell apoptosis. The differences of
infiltrating cytotoxic cells and related AI observed in
OLP and CLP are in keeping with the clinical
behaviors that distinguish these LP variants.