Novel ELISA systems for antibodies to desmoglein 1 and 3: correlation of disease activity with serum autoantibody levels in individual pemphigus patients

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are intraepidermal blistering skin diseases. PV is characterised by autoantibodies directed against desmoglein (Dsg) 3 and in patients with the mucocutaneous variant also against Dsg 1, whereas in PF, only Dsg 1 is targeted. Here, ectodomains of Dsg 3 and Dsg 1 were recombinantly expressed in a human cell line (HEK293) and applied as authentic solid phases in ELISA test systems. Autoantibodies against Dsg 3 and/or Dsg 1 could be detected in 71 (100%) of 71 PV sera and against Dsg 1 in 48 (96%) of 50 PF sera. Control sera showed reactivity with Dsg 3 and Dsg 1 in 0.2% and 0.7%, respectively, of 401 healthy blood donors and in 2.1% of 48 randomly selected patients with bullous pemphigoid. No reactivity with Dsg 1 and 3 was detected in 21 patients with linear IgA disease. For both pemphigus variants, a statistically significant correlation between clinical severity and autoantibody levels was observed as demonstrated for 10 PV and 5 PF patients. In conclusion, the use of the ectodomains of Dsg 3 and 1 as target antigens expressed in a human cell line resulted in sensitive and specific ELISA systems for both diagnosis and monitoring of PV and PF.