Cicatricial (Mucous Membrane) Pemphigoid Workup

Updated: May 03, 2017
  • Author: Manuel Valdebran, MD; Chief Editor: Dirk M Elston, MD  more...
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Workup

Laboratory Studies

The histologic findings, DIF results, and IIF results of mucous membrane pemphigoid (MMP) (cicatricial pemphigoid), BP, and EBA are similar; differentiation between these three entities depends on the clinical presentation.

Criteria for the diagnosis of  mucous membrane pemphigoid include an appropriate clinical presentation, histology demonstrating a subepidermal blistering process (as described below), and DIF results showing continuous deposits of any one or the combination of the following along the epithelial basement membrane zone: IgG, IgA, and/or C3. DIF study can be used to categorize the process as an autoimmune blistering disease, but it cannot be used to discriminate between  mucous membrane pemphigoid, BP, EBA, or anti-p200 pemphigoid.

IIF study of patients' sera depicts circulating antibasement membrane zone specific for IgG in 20% of patients, and, when present, it usually has a low titer (1:10-1:20).

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Imaging Studies

For evaluation of the upper airway or the esophagus, CT scans, barium swallows, or other imaging studies may be helpful. In patients with anti–laminin-332 mucous membrane pemphigoid (MMP), imaging may be required as part of a malignancy search.

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Other Tests

DIF study should be performed on noninvolved perilesional skin or mucous membranes. Patients with mucous membrane pemphigoid (MMP) typically demonstrate linear deposits of complement and IgG at the dermoepidermal junction. The most commonly assayed complement component is C3; however, C4, properdin, and other complement components have been described. Linear deposits of IgG are detectable in 25% of patients. Linear deposits of IgA, in addition to IgG, have been reported in 20% of patients in one series. This pattern of DIF is also seen in patients with BP and EBA, and DIF assay cannot be used to differentiate among these disorders. Conjunctival specimens have been reported to be less sensitive than biopsy specimens of oral mucosa on DIF results.

IIF assay detects the presence of circulating antibodies directed against normal epithelial basement membrane in the sera of patients who are affected. In patients with  mucous membrane pemphigoid, IIF assay reveals circulating IgG in 20% of patients, typically a low titer. When healthy human skin preincubated in 1 mol/L sodium chloride (salt-split skin) is used as a substrate, autoantibodies in patients with  mucous membrane pemphigoid associated with reactivity to BP180 bind to the epidermal roof. IIF results demonstrate a similar localization in patients with BP. Patients with autoantibodies associated with laminin-332 have circulating autoantibodies that bind to the blister floor, similar to that in patients with EBA. One laboratory has reported an increased sensitivity by IIF study by concentrating serum samples prior to assay.

Immunoblot (Western blot), immunoprecipitation, and immunoelectron microscopy are investigational tools used to better define target antigens. By immunoblot (Western blot) and immunoprecipitation, patients with  mucous membrane pemphigoid can have autoantibodies directed against BP180 (180 kd), BP230 (230 kd), and laminin-332. Enzyme-linked immunoassays using recombinant target antigens may ultimately be available to characterize autoantibody reactivity.

Routine laboratory studies are not helpful in establishing the diagnosis of  mucous membrane pemphigoid. Most hematologic studies are within the reference range. Laboratory values that may be elevated include immunoglobulins, erythrocyte sedimentation rate, and acute phase reactants.

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Histologic Findings

Biopsies specimens can be taken from a vesicle or perilesional tissue adjacent to an erosion. In oral lesions, it is recommended to avoid gingival biopsies.

Histopathologic features typically include the following [12, 13] :

  • Subepithelial blister
  • Infiltrate containing plasma cells, neutrophils, and eosinophils localized in the lamina propria
  • DIF showing linear deposits of IgG and C3 in basement membrane zone; sometimes, linear deposition of Ig A can also be present along with IgG and C3, which suggests mucous membrane pemphigoid (MMP).
  • Scar tissue may be seen in older or recurrent lesions

These histologic features can also be seen in other autoimmune subepidermal blistering diseases, including cell-poor BP, EBA, and linear IgA bullous dermatosis. The histologic features of porphyria cutanea tarda and variegate porphyria also may resemble  mucous membrane pemphigoid.

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