Autoantibodies in patients with oral lupus erythematosus, lichen planus and leukoplakia. An aid in diagnosis.

Of 35 patients with oral discoid lupus lesions, 9 (25%) were diagnosed as Systemic (SLE) and 26 as Discoid (dle) lupus erythematosus. Antibodies to whole nuclei (ANAL), dsDNA (anti-DNA ab) and extractable nuclear antigens (anti-RNP ab, anti-Sm ab) as well as serum immunoglobulin levels (Ig) were determined in these patients, in 20 patients with reticular oral lichen planus (LP) and 20 with homogeneous oral leukoplakia (LEUK). High IgG ANA titres were found in the SLE cases, highly increased anti-DNA ab in 6 SLE cases (67%) and one DLE case (4%), slightly increased anti-DNA ab in 9 DLE (35%) but only two (5%) of the LP nd LEUK cases. The prevalence of autoantibodies and increased anti-DNA ab did not differ significantly between DLE cases with oral lesions only and those with cutaneous lesions as well. Increased Ig were present in 6 SLE (67%), 8 DLE (31%), and 3 LEUK (15%) but none of the LP cases. High ANA titres and/or elevated anti-DNA ab disclosed 8 of the 9 SLE and one of 26 DLE cases. Slightly elevated anti-DNA ab and elevated Ig indicated the diagnosis in 9 and 8, respectively, of the 26 DLE cases. It is concluded that determination of ANA, anti-DNA ab and Ig is of diagnostic importance in patients with verified or suspected oral discoid lupus lesions.