What is the utilility of desmoglein ELISA in pemphigus patient’s follow up?
Patients with pemphigus vulgaris (PV) and pemphigus foliaceus (PF) have circulating autoantibodies in their serum against the cell surface of keratinocytes. These antibodies are directed against two glycoproteins, members of the cadherin family that have been called desmogleins (Dsg). In PF the antigen is a 160-kD protein called Dsg1. In PV the main antigen is a 130-kD protein called Dsg3, although around 50% of the patients also have antibodies against Dsg1. These last group of patients corresponds to the ones with mucocutaneous lesions. In the last 10 years an ELISA test using the extracellular domain of Dsg1 and Dsg3 has been developed and used in clinical practice. This test was initially used as a tool for diagnosis, but it has also been employed as a tool for the follow up and monitoring of these patients.
In a recent study of Abasq and coworkers from France published in the May issue of the Archives of Dermatology, the authors investigated the real value of Dsg1 and Dsg3 ELISA test in the monitoring of patients with pemphigus. In a retrospective study of 26 pemphigus patients (19 with PV and 7 with PF) the authors show that there is dissociation between the ELISA values of antibodies against Dsg1 and Dsg3. They show that both in patients with PV and PF, there was a close correlation of antibodies against Dsg1 and disease activity, and that a high level of antibodies can have a good predictive value for the occurrence of a skin relapse in these patients. On the other side, antibodies against Dsg3 in PV did not have a good correlation with disease activity (most patients had high levels of antibodies independently of disease activity). This dissociation has to be known by the physicians taking care of these patients in order to take the optimal decisions when the ELISA titers are rising or are persistently high.
ELISA Testing of Anti–Desmoglein 1 and 3 Antibodies in the Management of Pemphigus
Abasq C. et al.
Arch Dermatol 2009;145:529-535.
Objective: To assess the predictive value of anti–desmoglein (Dsg) 1 and anti-Dsg3 antibody (Ab) enzymelinked immunosorbent assay (ELISA) values for the occurrence of relapses in pemphigus.
Design: Retrospective study.
Setting: Dermatology departments from 13 university hospitals in France.
Patients: The study population comprised 26 patients with typical clinical, histologic, and immunofluorescence findings of pemphigus, who were followed up over a 17-month period.
Main Outcome Measures: Serial anti-Dsg1 and anti-Dsg3 Ab ELISA values were recorded during the patients’ follow-up examinations and correlated with the occurrence of skin and/or mucosal relapses.
Results: A significant reduction of anti-Dsg1 (P .001) and anti-Dsg3 (P<.001) Ab ELISA values was observed in serum samples from patients with pemphigus foliaceus or pemphigus vulgaris after the initial treatment. During the long-term follow-up, anti-Dsg1 Ab ELISA values correlated with the course of skin lesions (P=.03); the 20 U/mL cutoff for the anti-Dsg1 Ab ELISA value provided a 79% positive and an 84% negative predictive value for the occurrence of cutaneous relapses. No correlation was observed between anti-Dsg3 Ab ELISA values and the course of mucosal lesions (P=.13). Anti-Dsg3 Ab ELISA values higher than the 14-U/mL cutoff were observed in 5 of the 5 patients with relapse and in 10 of the 13 patients with ongoing mucosal remission, providing a 100% sensitivity but a poor specificity of 23%. A cutoff value of 130 U/mL for anti-Dsg3 Abs was calculated based on the receiver operating characteristics curve and provided an 84% positive and an 81% negative predictive value.
Conclusions: Anti-Dsg1 Ab ELISA values are more closely correlated than anti-Dsg3 Ab ELISA values with the course of the disease in patients with pemphigus vulgaris or pemphigus foliaceus. This should be taken into account for the management of patients with pemphigus.
