Immunological Methods for the Diagnosis of Oral Mucosal Diseases

S. Sun; B. Zhong; W. Li; X. Jin; Y. Yao; J. Wang; J. Liu; H. Dan; Q. Chen; X. Zeng

Disclosures

The British Journal of Dermatology. 2019;181(1):23-36. 

In This Article

Biochemical Tests

In recent years, the diagnostic spectrum of AIBDs has been expanded considerably. Biochemical tests, including enzyme-linked immunosorbent assay (ELISA), immunoblotting (IB) and immunoprecipitation (IP), are useful for diagnosing AIBDs. A case reported two patients with initial diagnoses of OLP and PV who were subsequently found to have PNP by positive serology results.[35]

Circulating antibodies against desmoglein-1 (Dsg1), desmoglein-3 (Dsg3), envoplakin, BP230, BP180, type VII collagen, laminin γ1 (e.g. USCN Life Science. Wuhan, China; ELK Biotechnology, Wuhan, China) and laminin 332/laminin 5 (e.g. Cusabio Technology LLC, Wuhan, China) can be detected in serum samples with commercially available ELISA kits. A novel multivariant ELISA consisting of six recombinant immunodominant forms of AIBD antigens (the first six antigens mentioned above) can be used in routine diagnosis of AIBDs.[36] In recent years, some novel ELISAs and commercially available ELISA kits for AIBDs have gradually appeared, such as mammalian ELISAs for the detection of IgG anti-desmocollin autoantibodies and a novel kit named the 'MESACUP anti-Skin profile TEST', which can be used for rapid diagnosis of AIBDs (especially for overlapping disorders).[37,38] Unfortunately, the 'MESACUP' seems not to be in manufacture currently.

IB and IP, which can confirm the presence of antibodies against multiple epitopes of antigens, have made a significant contribution to elucidating the antigenic sites and differential diagnosis. IB can be a supplementary test when SSS test shows atypical features or negative results of suspected AIBDs.[39–41] Furthermore, IP is mainly used for highly suspected PNP with negative results of IIF on rat bladder epithelium.

Biochemical tests have been used to identify various target antigens (Table 1). We also list the diagnostic sensitivity of ELISA, IB and IP for PV,[26,27,42,43] PNP,[18,29,44–46] MMP,[47,48] and LAD[49] (Table 3).

Protein Microarrays

Protein microarrays, the emerging field, can analyse protein–protein interactions and identify disease-related autoantigens with a performance equivalent to that of ELISA.[50] One of the most widespread applications in protein microarrays is screening autoantibodies from patient serum using various antigens printed on a chip, which can provide a high-throughput and multiplex analysis of a large number of serum samples against hundreds of antigens.[51] The disadvantage of IB and ELISA compared with protein microarrays is the limitation of identifying numerous proteins during one attempt. Identification of these autoantigens by protein microarrays can be useful in the early diagnosis; they may be used as prognostic markers of AIBDs.

A large number of protein array chips, which can be customized by users, are commercially available (Invitrogen/Thermo Fisher Scientific, Carlsbad, CA, U.S.A.). However, Tabakman et al.[52] reported that plasmonic protein chips, which were commercially available from Plasmonix, Inc. (no longer trading), showed higher sensitivity and broad dynamic range when compared with previous nitrocellulose and glass slides. However, these chips are not currently produced.

Currently, for AIBDs, protein microarrays have been mainly used in PV. The technology can identify novel targets, explore the relationship between autoantibody reactivity and disease reactivity, and identify Dsg3 epitopes recognized by autoantibodies in patients with PV.[53–57] This may help to elucidate the immunopathogenic mechanisms, explain individual differences in response to treatment and disease severity, predict the course of the disease, and develop precisely targeted and individualized therapies. Protein microarrays may serve as a future conventional diagnostic method with high sensitivity and specificity in AIBDs.

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