Table 1.

Clinical characteristics, target autoantigens and diagnosis of the intraepithelial autoimmune bullous skin disorders (AIBDs).

Diseases	Clinical Features	Autoantigens [3]	Diagnosis [3,4]
Pemphigus vulgaris (PV)	Flaccid blisters and painful erosions on skin with propensity to strained and intertriginous areas [5,6] Extensive oral mucosal involvement precedes the skin lesions	Dsg1,3	H&E: Suprabasal acantholysis, tombstone pattern of the basal keratinocytes DIF: Intercellular deposition of IgG/C3 IIF: Intercellular deposition of IgG ELISA: Anti-Dsg3 and/or anti-Dsg1 antibodies
Pemphigus foliaceus (PF)	Flaccid blisters and erosions affect exclusively the cornified skin and spared the mucosal regions Usually in a seborrheic distribution	Dsg1	H&E: Acantholysis and spongiosis within the stratum granulosum DIF: Intercellular deposition of IgG/C3 IIF: Intercellular deposition of IgG ELISA: Anti-Dsg1 antibodies
Pemphigus erythematosus (PE)	Blisters on the erythematous plaques at the nose, nasolabial folds and malar regions [7]	Dsg1	H&E: The same as PF DIF: Intercellular and shaggy basement membrane deposition of IgG/C3 IIF: Intercellular deposition of IgG ELISA: Anti-Dsg1 antibodies Positive serum antinuclear antibody
IgA pemphigus	Vesiculopustular lesions on the erythematous plaques in an annular morphology at the trunk and proximal extremities [8]	Dsc1,2,3 & Dsg1,3	H&E: Prominent intraepidermal neutrophilic infiltrates DIF: Intercellular deposition of IgA/C3 IIF: Intercellular deposition of IgA ELISA: Anti-Dsc1,2,3 and anti-Dsg1,3 IgA antibodies
Paraneoplastic pemphigus (PNP)	Blisters, erosions or lichenoid lesions on the skin Extensive and intractable stomatitis Related to thymoma [9] and hematological malignancies [10,11,12]	Envoplakin, periplakin, BP230, Dsg1,3, desmoplakins, epiplakin, α-2- macroglobulin- like antigen-1, and plectin	H&E: Overt interface/lichenoid infiltrates with dyskeratotic cells, foci suprabasal acantholysis DIF: Intercellular and basement membrane deposition of IgG and/or C3 IIF: Intercellular deposition of IgG (monkey esophagus and monkey/rat bladder [13]) 1 ELISA: Common anti-Dsg3 and anti-envoplakin antibodies

Abbreviations: H&E, hematoxylin and eosin stain. DIF/IIF, direct/indirect immunofluorescence. ELISA, enzyme-linked immunosorbent assay. IgA/IgG, immunoglobulin A/G. Dsg, desmoglein. Dsc, desmocollin. ¹ IIF is commonly performed on monkey esophagus. The urothelium of monkey and rat bladder serve as excellent substrates for detecting anti-plakin autoantibodies to distinguish PNP from other pemphigus diseases.