Human Polyomavirus 6 Detected in Cases of Eosinophilic Pustular Folliculitis.

BACKGROUND Human polyomaviruses (HPyVs) have been associated with several cutaneous inflammatory conditions. More investigation is needed to identify further presentations of cutaneous pathology associated with HPyVs. Our aim was to investigate the possible association of skin-tropic HPyVs with folliculitis, particularly eosinophilic pustular folliculitis (EPF). METHODS This study included 55 Japanese patients, comprising 13 patients with EPF and 42 patients with suppurative folliculitis. HPyV DNAs were detected by quantitative polymerase chain reaction. Expression of viral antigen and geographically related viral genotypes were also assessed. RESULTS Human polyomavirus 6 (HPyV6) DNA was found in nine of 13 (69%) patients with EPF, a rate significantly higher than that found in suppurative folliculitis (1/42; 2%). Of the seven HPyV6 DNA-positive EPF specimens analyzed, four were positive for HPyV6 small T-antigen. All the HPyV6 strains detected in this study were of the Asian/Japanese genotype. CONCLUSIONS The predominant detection of HPyV6 DNA and the expression of viral antigen suggest a possible association between HPyV6 infection and EPF in a subset of patients. Worldwide studies are warranted to determine whether Asian/Japanese genotype HPyV6 is associated preferentially with the incidence and pathogenesis of this eosinophil-related skin disease that has an ethnic predilection for the East Asian population.