Quantitative assessment of apoptosis in oral lichen planus

Objective. The aims of this study were to examine the frequency of apoptose s in oral lichen planus by in situ end labeling, to ascertain whether this technique is as sensitive as conventional histologic analysis, and to exami ne the effect of lymphocytic infiltration. Study design, Numbers of apoptoses in hematoxylin-eosin stained sections we re compared with numbers of apoptotic nuclei identified by in situ end labe ling in oral lichen planus (n = 26) and normal buccal epithelium (n = 8). I mmunohistochemical staining with MIB-1 and for Bcl-2 and Bar enabled possib le regulatory pathways to be investigated. Results. In oral lichen planus, approximately 1 apoptotic cell was detected per millimeter of basal layer, cell death increasing with lymphocytic infi ltration. Epithelial cell proliferation did not correlate with apoptosis. B cl-2 expression was weak or absent in basal cells, and Bar was localized to upper prickle cells. Conclusions. Increased numbers of apoptoses were detected in oral lichen pl anus, especially in association with lymphocytic infiltration, higher numbe rs being seen with hematoxylin-eosin staining than with in situ end labelin g.