Subclinical oral involvement in patients with endemic pemphigus foliaceus

Abstract

Background: We have described a variant of endemic pemphigus foliaceus (EPF) in El Bagre area known as pemphigus Abreu-Manu. Our previous study suggested that Colombian EPF seemed to react with various plakin family proteins, such as desmoplakins, envoplakin, periplakin BP230, MYZAP, ARVCF, p0071 as well as desmoglein 1.

Objectives: To explore whether patients affected by a new variant of endemic pemphigus foliaceus (El Bagre-EPF) demonstrated oral involvement.

Materials and methods: A case-control study was done by searching for oral changes in 45 patients affected by El Bagre-EPF, as well as 45 epidemiologically matched controls from the endemic area matched by demographics, oral hygiene habits, comorbidities, smoking habits, place of residence, age, sex, and work activity. Oral biopsies were taken and evaluated via hematoxylin and eosin staining, direct immunofluorescence, indirect immunofluorescence, confocal microscopy, and immunohistochemistry.

Results: Radicular pieces and loss of teeth were seen in in 43 of the 45 El Bagre-EPF patients and 20 of the 45 controls (P < 0.001) (confidence interval [CI] 98%). Hematoxylin and eosin staining showed 23 of 45 El Bagre-EPF patients had corneal/subcorneal blistering and lymphohistiocytic infiltrates under the basement membrane zone and around the salivary glands, the periodontal ligament, and the neurovascular bundles in all cell junction structures in the oral cavity; these findings were not seen in the controls (P < 0.001) (CI 98%). The direct immunofluorescence, indirect immunofluorescence, confocal microscopy, and microarray staining displayed autoantibodies to the salivary glands, including their serous acini and the excretory duct cell junctions, the periodontal ligament, the neurovascular bundles and their cell junctions, striated muscle and their cell junctions, neuroreceptors, and connective tissue cell junctions. The autoantibodies were polyclonal. IgA autoantibodies were found in neuroreceptors in the glands and were positive in 41 of 45 patients and 3 of 45 controls.

Conclusions: Patients affected by El Bagre-EPF have some oral anomalies and an immune response, primarily to cell junctions. The intrinsic oral mucosal immune system, including IgA and secretory IgA, play an important role in this autoimmunity. Our data contradict the hypothesis that pemphigus foliaceus does not affect the oral mucosa due to the desmoglein 1-desmoglein 3 compensation.

Keywords: IgA; cell junctions; endemic pemphigus foliaceus; oral mucosa; salivary glands; secretory immunoglobulin A.

Figure 1

(a) Missing teeth in one El Bagre–EPF patient. (b) H&E staining of the oral mucosa, showing edema in the mucosa; in the dermis, a lymphohistiocytic infiltrate (black arrow) and dilation of a blood vessel (blue arrow) (200×). (c) DIF showing positive staining with FITC conjugated anti-fibrinogen antibodies in intracorneal blister (light green staining; white arrow) and pericytoplasmic staining of the epidermal keratinocytes (light green staining; red arrow) (200×) and stain in the vessels (yellow-green staining; light blue arrow). (d) DIF showing positive staining with FITC conjugated IgG antibodies against the BMZ (green staining; yellow arrow), as well as against upper dermal blood vessels with ULEX (yellow staining, resulting from the colocalization of FITC [green] and Texas red [red]; light blue arrow) (200×). (e) DIF showing positive staining with FITC conjugated fibrinogen antibodies (green staining), colocalizing with MYZAP Alexa Fluor 555 against skeletal muscle (yellow arrow), as well as their cell junctions (red staining; white arrows) (200×). (f) DIF showing positive staining with FITC conjugated C3c antibodies against the acini of the salivary glands (yellow staining; red arrow) and colocalizing with MYZAP in a salivary duct with Alexa Fluor 555 (white arrow; 400×). [Copyright: ©2018 Abreu-Velez et al.]

Figure 2

(a) DIF showing positive dot staining with FITC conjugated IgG antibodies against epithelial cell junctions (light green staining; white arrow) (200×) and in the corneal layer (light green staining; red arrow). (b) DIF showing positive staining with FITC conjugated IgG antibodies against the corneal layer (yellow staining; yellow arrow) and dot cell junction staining in epithelial cells (light green staining; white arrow). ARVCF staining with Alexa Fluor 555 is noted in a salivary gland duct (red staining; white arrow) (200×) and in the corneal layer (red staining; yellow arrow). (c–f) Confocal microscopy, using multiple channels of fluorescence. In c, we used antibody to IgM FITC channel (excitation/emission, 495/519 nm); in (d) an antibody to p0071 (Texas red, 555 channel) (excitation/emission, 555/568 nm); in (e) a DAPI channel (blue) (excitation/emission, 360/460 nm); and in f, the combination of all showing a perfect colocalization against neuroreceptors in a salivary gland (in c–f, white arrows, 1,000×). [Copyright: ©2018 Abreu-Velez et al.]

Figure 3

(a) IHC positive staining for metallothionein between oral mucosal cell junctions (black arrow) as well as at the BMZ (brown staining; red arrow; 200×). (b) IHC positive staining for IgA on neurovascular dermal structures (brown staining; red arrow) (100×). (c) IHC positive staining mesenchymal-endothelial junctions in dermal connective tissue cell junctions (brown staining; red arrow)(200×). (d) DIF, showing positive staining with IgA FITC conjugate on dermal connective tissue cell junctions (black arrow) colocalizing with ARVCF conjugate with Alexa Fluor 555 (400×). (e) IHC positive staining with metallothionein in a salivary gland (brown staining; red arrow)(400×). (f) DIF positive staining with FITC conjugated C1q, colocalizing with Texas red DP I–II in the oral mucosa (black arrow, 1,000×). [Copyright: ©2018 Abreu-Velez et al.]