Herpes simplex virus 1 and cytomegalovirus are associated with pemphigus vulgaris but not with pemphigus foliaceus disease

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 ( HSV 1/2), 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. HSV 1/2 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‐ HSV 1 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. HSV 1 was confirmed by DIF and qPCR on oral samples from patients with PV . Lack of HSV 1 expression in the oral mucosa of patients with PF corroborate that immunosuppressive therapy cannot be the main cause for HSV 1 replication in PV disease.