Development of antigen-specific ELISA for circulating autoantibodies to extracellular matrix protein 1 in lichen sclerosus
Noritaka Oyama, … , Martin M. Black, John A. McGrath
Noritaka Oyama, … , Martin M. Black, John A. McGrath
Published June 1, 2004
Citation Information: J Clin Invest. 2004;113(11):1550-1559. https://doi.org/10.1172/JCI20373.
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Article Dermatology

Development of antigen-specific ELISA for circulating autoantibodies to extracellular matrix protein 1 in lichen sclerosus

Abstract

Lichen sclerosus is a common, acquired chronic inflammatory skin disease of unknown etiology, although circulating autoantibodies to the glycoprotein extracellular matrix protein 1 (ECM1) have been detected in most patients’ sera. We have examined the nature of ECM1 epitopes in lichen sclerosus sera, developed an ELISA system for serologic diagnosis, and assessed clinicopathological correlation between ELISA titer and disease. Epitope-mapping studies revealed that lichen sclerosus sera most frequently recognized the distal second tandem repeat domain and carboxyl-terminus of ECM1. We analyzed serum autoantibody reactivity against this immunodominant epitope in 413 individuals (95 subjects with lichen sclerosus, 161 normal control subjects, and 157 subjects with other autoimmune basement membrane or sclerosing diseases). The ELISA assay was highly sensitive; 76 of 95 lichen sclerosus patients (80.0%) exhibited IgG reactivity. It was also highly specific (93.7%) in discriminating between lichen sclerosus and other disease/control sera. Higher anti-ECM1 titers also correlated with more longstanding and refractory disease and cases complicated by squamous cell carcinoma. Furthermore, passive transfer of affinity-purified patient IgG reproduced some histologic and immunopathologic features of lichen sclerosus skin. This new ELISA is valuable for the accurate detection and quantification of anti-ECM1 autoantibodies. Moreover, the values may have clinical significance in patients with lichen sclerosus.

Authors

Noritaka Oyama, Ien Chan, Sallie M. Neill, Andrew P. South, Fenella Wojnarowska, Yoshio Kawakami, David D’Cruz, Kirti Mepani, Graham J. Hughes, Balbir S. Bhogal, Fumio Kaneko, Martin M. Black, John A. McGrath

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Figure 4

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Preabsorption assays for affinity-purified lichen sclerosus sera with re...
Preabsorption assays for affinity-purified lichen sclerosus sera with recombinant proteins. (A) Immunostaining with anti-ECM1 rabbit polyclonal antibody on normal human skin displays intracellular labeling in the lower epidermis, particularly in basal and suprabasal cell layers. Inset shows labeling of dermal blood vessels. (B) Similar staining pattern was obtained using affinity-purified IgG fractions from ΔDs/COOH-positive lichen sclerosus sera. (C) Before immunostaining, the affinity-purified IgG fractions from ΔDs/COOH-positive sera were incubated with an excess of ΔDs/COOH recombinant. This results in a marked reduction in labeling intensity (c.f. Figure 4B). (D) Before immunostaining, the affinity-purified IgG fractions from a dual ΔNH2-positive and ΔDs/COOH-positive lichen sclerosus serum were incubated with an excess of either ΔNH2 or ΔDs/COOH recombinants. No alteration occurred in the original labeling intensity. (E) Before immunostaining, the affinity-purified IgG fractions from a dual ΔNH2-positive and ΔDs/COOH-positive sera were incubated with a mixture of both the ΔNH2 and ΔDs/COOH recombinants or with (F) control recombinant protein BP180 NC16A. Note the marked signal reduction in (E) but not in (F). Scale bar: 50 ∝m.