title: A higher correlation of the antibody activities against the calcium-dependent epitopes of desmoglein 3 quantified by ethylenediaminetetraacetic acid-treated enzyme-linked immunosorbent assay with clinical disease activities of pemphigus vulgaris.
abstract: BACKGROUND
  Nonpathogenic anti-desmoglein (Dsg) 3 antibodies can be found in pemphigus vulgaris (PV) patients' sera. Previously, ethylenediaminetetraacetic acid (EDTA)-treated enzyme-linked immunosorbent assay (ELISA) was found to detect only nonpathogenic anti-Dsg3 antibodies against the non-calcium (Ca(2+))-dependent epitopes.
  
  
  OBJECTIVE
  We examined whether the calculated anti-Dsg3 antibody titer for Ca(2+)-dependent epitopes, using the conventional and EDTA-treated ELISAs, correlated better with the disease activity of PV.
  
  
  METHODS
  We analyzed 123 serum samples from 19 PV patients. Of these samples, there were 52 samples from 15 PV patients obtained in asymptomatic phases. The difference between conventional Dsg3 ELISA index and EDTA-treated Dsg3 ELISA index was calculated as the anti-Dsg3 antibody activity for Ca(2+)-dependent conformational epitopes (conformational Dsg3 ELISA index). We analyzed the correlation between Dsg3 ELISA index values and the pemphigus disease area index (PDAI). Moreover, we examined whether the conformational Dsg3 ELISA index fluctuated in parallel with the disease activity during clinical courses of 6 PV patients. We evaluated the pathogenicity of anti-Dsg3 antibodies detected in remission phases using a dissociation assay.
  
  
  RESULTS
  The conventional Dsg3 ELISA index showed a high positive rate in the asymptomatic phase of PV. By contrast, the conformational Dsg3 ELISA index showed a much closer correlation to the disease activity when monitored in individual cases. Nonpathogenic anti-Dsg3 antibodies were detected in these cases.
  
  
  CONCLUSIONS
  The conformational Dsg3 ELISA index reflected the pathogenicity of anti-Dsg3 antibodies more accurately than the conventional Dsg3 ELISA index. Using both conventional and EDTA-treated ELISAs would be useful in monitoring the disease activity of PV.
authors.affiliation: Department of Dermatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kamiya
authors.forename: Yumi
authors.initials: Y
authors.lastname: Aoyama
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Shirafuji
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Hamada
authors.forename: Shin
authors.initials: S
authors.lastname: Morizane
authors.forename: Kazuyasu
authors.initials: K
authors.lastname: Fujii
authors.forename: Keiji
authors.initials: K
authors.lastname: Iwatsuki
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000276:immunology* / Q000378:metabolism; D002908:Chronic Disease; D051184:Desmoglein 3 / Q000276:immunology* / Q000378:metabolism; D004492:Edetic Acid / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D000939:Epitopes; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D010392:Pemphigus / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012074:Remission Induction; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; C071894:DSG3 protein, human; D051184:Desmoglein 3; D000939:Epitopes; D007166:Immunosuppressive Agents; D004492:Edetic Acid; D002118:Calcium