Absence of human herpesvirus 8 in pemphigus and bullous pemphigoid

Pemphigus and pemphigoid are vesicobullous disorders characterized by an autoimmune attack on intercellular or basement membrane antigens, resulting in defective keratinocyte adhesion. Recently there have been reports of human herpesvirus 8 (HHV8) associated with cases of pemphigus using polymerase chain reaction (PCR) techniques, in situ hybridization, and serologic data. However, data to date is contradictory, and the relationship between this virus and autoimmune vesiculobullous disorders is unclear. No reports have attempted immunohistochemical localization of HHV8 in tissue affected by PV or BP. We studied immunohistochemical expression of HHV8 on paraffin-embedded tissue in 10 cases of pemphigus vulgaris (PV), 1 case of pemphigus foliaceous (PF) and 14 cases of bullous pemphigoid (BP). Five cases of normal skin were included as controls. Confirmatory PCR for HHV8 was performed on 4 selected cases, including 2 cases of PV and 2 cases of BP. Immunohistochemistry failed to identified the presence of HHV8 in all cases of PV (10 cases), PF (1 case) and BP (14 cases). Molecular detection of HHV8 DNA was not detected in selected PV (2 cases) and BP (2 cases). Published studies have shown contradictory evidence regarding the presence of HHV8 in vesiculobullous diseases such as pemphigus and pemphigoid. Our results refute a causal relationship between HHV8 and PV, PF and BP.