Antinuclear antibodies in patients with lichen planus

Lichen planus (LP) is a mucocutaneous syndrome of yet uncertain pathogenesis, and it has usually been considered to be a dermatosis without antinuclear antibodies (ANA) nor other specific auto-antibodies. Over 10 years ago a series of indirect immunofluorescence researches with patients' lesional skin and serum disclosed the presence of lichen planus specific antigens (LPSA). After this, a number of substrates have been submitted for evaluation. In this study we have carried out indirect immunofluorescent test in relation with different substrates, with the aim of verifying whether the negative results previously obtained were due to poor sensitivity of the substrates employed. Subsequently we have compared the results obtained in the erosive forms of LP with those obtained in the non-erosive forms. We have concluded that rat oesophagus is a better substrate for the detection of ANA in patients with LP, as it has proved to have a positivity rate of 40.42%. Monkey oesophagus has provided a rate of 27.6%, and HEP-2 cells and rat liver have proved to be unsuitable. In addition, we have observed that the frequency of ANA is higher in the erosive forms of LP (P = 0.0389). In this article we demonstrate that the presence of ANA in patients with LP depends on the substrate employed, the most suitable substrate being rat oesophagus. Also, we demonstrate that ANA is more frequently observed in patients with erosive LP.