Circulating immune complex studies on patients with oral lichen planus

To investigate the role of systemic factors such as age, diabetes, and hypertension in the formation of subepithelial immune deposits in oral lichen planus (OLP) we performed circulating immune complex CIC determinations by polyethylene glycol precipitation in sera of patients with OLP, diabetes mellitus, and hypertension and in sera of healthy control subjects. We examined patients with leukoplakia as a control group with oral keratosis but no OLP. Forty percent of the OLP patients were suffering from diabetes, hypertension, or both. The occurrence of CIC positivity was higher in the OLP group with diabetes than in the group with OLP only. However, we could not find CIC positivity in our control patients with diabetes. The almost equal distribution of hypertension among, patients with OLP who tested positive for CIC and those who tested negative does not seem to support the hypothesis that this factor causes this factor causes the CIC positivity in OLP. The same applies to other assumed factors such as age, medication, dental foci, or metal framework. In summary, we support the idea that CIC positivity may be the consequence of lichen itself, but diabetes and hypertension contribute to the development of erosive OLP lesions.