Sensitivity and specificity of clinical, histologic, and immunologic features in the diagnosis of paraneoplastic pemphigus

Background: Paraneoplastic pemphigus (PNP) is an autoimmune blistering dise ase characterized by the production of autoantibodies mainly directed again st proteins of the plakin family. An overlapping distribution of autoantibo dy specificities has been recently reported between PNP, pemphigus vulgaris (PV), and pemphigus foliaceus (PF), which suggests a relationship between the different types of pemphigus. Objective: Our purpose was to evaluate the sensitivity and the specificity of clinical, histologic, and immunologic features in the diagnosis of PNP. Methods: The clinical, histologic, and immunologic features of 22 PNP patie nts were retrospectively reviewed and compared with those of 81 PV and PF p atients without neoplasia and of 8 PV and 4 PF patients with various neopla sms. Results: One clinical and 2 biologic features had both high sensitivity (82 %-86%) and high specificity (83%-100%) whatever the control group considere d: (1) association with a lymphoproliferative disorder, (2) indirect immuno fluorescence (IIF) labeling of rat bladder, and (3) recognition of the envo plakin and/or periplakin bands in immunoblotting. Two clinicopathologic and two biologic features had high specificity (87%-100%) but poor sensitivity (27%-59%): (1) clinical presentation associating erosive oral lesions with erythema multiforme-like, bullous pemphigoid-like, or lichen planus-like c utaneous lesions; (2) histologic picture of suprabasal acantholysis with ke ratinocyte necrosis, interface changes, or lichenoid infiltrate; (3) presen ce of both anti-epithelial cell surface and anti-basement membrane zone ant ibodies by IIF; and (4) recognition of the desmoplakin I and/or BPAG1 bands in immunoblotting. interestingly 45% of patients with PNP presented initia lly with isolated oral erosions that were undistinguishable from those seen in PV patients, and 27% had histologic findings of only suprabasal acantho lysis, which was in accordance with the frequent detection of anti-desmogle in 3 antibodies in PNP sera. Conclusion: The association with a lymphoproliferative disorder, the IIF la beling of rat bladder, and the immunoblotting recognition of envoplakin and /or periplakin are both sensitive and specific features in the diagnosis of PNP.