Comparison of 3 type VII collagen (C7) assays for serologic diagnosis of epidermolysis bullosa acquisita (EBA).
Seta, Vannina; Aucouturier, Francoise PhD; Bonnefoy, Jonathan PhD; Le Roux-Villet, Christelle MD; Pendaries, Valerie PhD; Alexandre, Marina MD; Grootenboer-Mignot, Sabine MD, PhD; Heller, Michel PhD; Lievre, Nicole; Laroche, Liliane MD, PhD; Caux, Frederic MD, PhD; Titeux, Matthias PhD; Hovnanian, Alain MD, PhD; Prost-Squarcioni, Catherine MD, PhD
[Article] Journal of the American Academy of Dermatology. 74(6):1166-1172, June 2016.

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Background: Serologic diagnosis of epidermolysis bullosa acquisita (EBA) relies on the detection of circulating autoantibodies to type VII collagen (C7).

Objective: We sought to compare the diagnostic performances of a commercialized enzyme-linked immunosorbent assay (ELISA) using C7 noncollagenous (NC) domains (C7-NC1/NC2 ELISA) and indirect immunofluorescence (IIF) biochip test on NC1-C7-expressing transfected cells (IIFT), with a full-length-C7 ELISA developed in our laboratory.

Methods: C7-NC1/NC2 ELISA, IIFT, and full-length-C7 ELISA were run on 77 nonselected consecutive EBA sera.

Results: C7-NC1/NC2 ELISA, IIFT, and full-length-C7 ELISA were positive, respectively, for: 30%, 27%, and 65% of the 77 sera; 43%, 32%, and 80% of 44 sera labeling the salt-split-skin (SSS) floor (F) by IIF (SSS/F ); 9%, 22%, and 47% of 32 SSS/F- sera; 28%, 28%, and 58% of classic EBA; 41%, 41%, and 82% of inflammatory EBA; and 18%, 0%, and 55% of mucous-membrane-predominant EBA. Significant differences for all sera were found between: the 2 ELISAs for the 77 sera, SSS/F and SSS/F- sera, and IIFT versus full-length-C7 ELISA.

Limitations: The retrospective design was a limitation.

Conclusion: C7-NC1/NC2 ELISA and IIFT sensitivities for serologic diagnoses of EBA were low. Full-length-C7 ELISA was significantly more sensitive and could serve as a reference test.

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