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Development of a novel ELISA system for detection of anti‐BP180 IgG and characterization of autoantibody profile in bullous pemphigoid patients
Author(s) -
Mariotti F.,
Grosso F.,
Terracina M.,
Ruffelli M.,
CordialiFei P.,
Sera F.,
Zambruno G.,
Mastrogiacomo A.,
Di Zenzo G.
Publication year - 2004
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.2004.06245.x
Subject(s) - epitope , autoantibody , bullous pemphigoid , recombinant dna , antigen , antibody , virology , pemphigoid , microbiology and biotechnology , epitope mapping , immunology , medicine , chemistry , biology , biochemistry , gene
Summary Background The NC16A immunodominant region of the bullous pemphigoid (BP) antigen BP180 has been used to develop several enzyme‐linked immunosorbent assays (ELISAs) as diagnostic tools for BP autoantibody detection. Objectives Because BP180 autoantibody reactivity is not restricted to NC16A, we have investigated the possibility of developing an ELISA based on selected epitopes additional to this immunodominant region. Methods Initially 78 BP sera were tested using an NC16A ELISA and IgG reactivity was detected in 64 BP sera (82%). The 14 NC16A‐negative BP sera were then analysed by immunological screening against seven BP180‐specific epitopes. Recombinant phages displaying BP180 epitopes were grown as plaques, blotted onto a nitrocellulose filter and incubated with BP sera. Results Three and five NC16A‐negative BP sera reacted with epitopes AA 1080–1107 and AA 1331–1404 of the BP180 ectodomain, respectively. Thus, a novel ELISA with GST‐1080 and GST‐1331 (GST‐1080/1331) was developed: 32 of 78 BP sera (41%) proved positive by this assay. The combined use of ELISAs with GST‐NC16A and GST‐1080/1331 detected IgG reactivity in 72 of 78 BP sera, increasing the sensitivity from 82% to 92%. In addition, autoreactivity against the three extracellular epitopes appeared to be related to the presence of both skin and mucosal involvement as assessed by Fisher's exact probability test. Conclusions Our findings further characterize the autoimmune response in BP by identifying a subgroup of NC16A‐negative patients who react with different BP180 extracellular epitopes. The developed ELISA system appears more sensitive than the ELISA based on NC16A alone and also informative about the epitope profile of BP patients.