Use of indirect immunofluorescence in the lupus erythematosus/lichen planus overlap syndrome: an additional diagnostic clue.

The lupus erythematosus (LE)/lichen planus (LP) overlap syndrome comprises a heterogeneous group of patients who demonstrate clinical, histologic, and immunopathologic characteristics of two diseases. We report six patients with the syndrome who were evaluated by a double-layer indirect immunofluorescence (IF) technic using patient serum and autologous lesional skin as substrate followed by conjugate. This test demonstrated intense staining of the stratum granulosum in two patients, a finding previously shown to be consistent with LP. A third patient developed criteria for the diagnosis of systemic LE with corroborating direct IF findings and a negative indirect IF assay. This preliminary study provides evidence for a possible way of distinguishing LE from LP in some patients with the overlap syndrome.