LAUSR

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are blistering autoimmune diseases that depend on interaction between genetic and environmental factors. Viral infections, like herpes simplex viruses 1 and 2 (HSV1/2), cytomegalovirus (CMV), Epstein‐Barr virus and dengue virus, could trigger or exacerbate pemphigus. IgM and IgG antibodies against these viruses in serum from PV and PF, their relatives and controls were determined. HSV1/2 expression was evaluated by direct immunofluorescence (DIF) and qPCR in affected or not oral mucosa from PV patients compared with uninjured PF mucosa. IgG anti‐HSV1 was higher in the PV group compared with all groups. IgG anti‐CMV resulted higher in PV group compared with PF patients and PV relatives. HSV1 was confirmed by DIF and qPCR on oral samples from patients with PV. Lack of HSV1 expression in the oral mucosa of patients with PF corroborate that immunosuppressive therapy cannot be the main cause for HSV1 replication in PV disease.