Destruction of basement membrane and cell infiltrates in oral lichen planus

Immunohistochemical staining analysis of oral lichen planus (OLP) using monoclonal antibodies (MoAbs) against the components of basement membrane (BM) and infiltrated cells was performed in 27 cases. Integrity of lining epithelial BM was more strictly elucidated by staining for laminin and type IV collagen than by fibronectin. Staining patterns of laminin were similar to type IV collagen. In the cases examined, continuity of BM was proven by laminin staining in 10 cases, partially destructive BM was seen in 9 cases and complete destruction of BM in 8 cases. Dividing OLP into 20 symptomatic (ulcerative/erosive) and 7 asymptomatic (non-ulcerative/-erosive) cases, intact BM could be observed in only 5 cases of the symptomatic group, while 5 cases of the other group possessed undamaged BM. The difference between the two groups was significant. Stromal and epidermal cell infiltrates, which were mainly composed of T cell subsets with accompanying Leu-M5 and 6-positive cells, were correlated with the condition of BM. Stromal Leu-M5+ and Leu-6+ cell infiltrates were clearly more dominant in laminin-negative (BM-destructed) cases than infiltrates in BM-intact cases. This relation was also found in epidermal infiltrates with the same manner of Leu-4 infiltration. From the above, it seems that the integrity of BM is concerned with cell infiltrates and clinical manifestations of OLP.