68 | fulminant sjs/ten-like pemphigus vulgaris with high ANTI-DSG1 titers and cmv reactivation: An immunological challenge

Introduction. Pemphigus vulgaris (PV) is an autoimmune blistering disease driven by IgG autoantibodies against desmoglein (Dsg) 1 and 3. Rare fulminant variants may mimic Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). We report an exceptionally severe SJS/TEN-like PV in a previously healthy woman, focusing on its immunological basis and management.Materials and Methods. Case report of a 55-year-old woman with an unremarkable history. The work-up included histology, direct (DIF) and indirect immunofluorescence (IIF), anti-Dsg1/Dsg3 ELISA, a viral panel and malignancy screening; disease activity was scored by PDAI.Results. The patient developed rapidly progressive mucocutaneous erosions evolving into extensive epidermal detachment (PDAI activity 25), without drug trigger or fever. Histology showed suprabasal acantholysis; DIF revealed intercellular IgG1 and C3; IIF was positive (1:80). ELISA demonstrated markedly elevated anti-Dsg1 (107.5 IU/mL) with only modest anti-Dsg3 (9.6 IU/mL). Anti-envoplakin was negative and malignancy screening unremarkable, while rat-bladder IIF was unavailable. CMV reactivation (IgM positive) was detected and treated with ganciclovir. The Dsg1-dominant, discordant profile together with complement-fixing IgG1/C3 deposition supports antibody- and complement-mediated acantholysis as drivers of the SJS/TEN-like phenotype. Combined rituximab and intravenous immunoglobulin achieved rapid re-epithelialization. At 12-month follow-up the patient was in complete clinical and serological remission (PDAI 0; anti-Dsg negative), with no malignancy.Conclusions. This case expands the clinical spectrum of PV, showing that high anti-Dsg1 titers, complement activation and CMV-related immune dysregulation can converge to produce a life-threatening SJS/TEN-like phenotype. Early B-cell-directed therapy combined with immunoglobulin can be life-saving, and prolonged oncological surveillance remains warranted.