Role of humoral mechanisms in etiology of lichen planus

To examine the role of IgA, CIC and component C3 as indicators of humoral immune response in the etiopathogenesis of oral erosive lichen planus (OELP).

The study comprised 19 patients with OELP whose samples of blood, saliva and tissue were obtained after carefully taken medical history and clinical examination. Samples of oral mucosa were taken from the site of lesion, i.e. exclusively from buccal mucosa (1 cm in width and length), and from the deep epithelium as well as a segment from the lamina propria. Determination of immunoglobulins in serum and saliva, and determination of component C3, was done using the micro-elisa technique by Rook&Cameron, Engvall and Ulman. Determination of CIC in serum and mixed saliva was done with the PEG (polyethylene glycol) method. Determination of immunoglobulin A and component C3 in biopsy material was done with direct immunofluorescence.

Levels of immunoglobulin A in serum in OELP during exacerbation were decreased (1.04±0.49 gr/l) and during remission increased (5.92±0.62) in comparison with the control group (p<0.001). Levels of CIC during exacerbation and remission were increased (p<0.001), and component C3 levels were increased in both examined phases in the examined group compared with the control group (p<0.05). Deposits of IgA were registered in one (5.88%) patient with OELP and component C3 was registered in 3 (17.64%) patients.

Changes in IgA values, as well as CIC and component C3, may correlate with changes in oral mucosa emphasizing the role of humoral immune response in the pathogenesis of oral lichen planus.