Epstein-Barr virus and human herpesvirus type 6 infection in patients with psoriasis.

The association of psoriasis with latent human herpesvirus infection has not been well described. To better understand the relationship between severe psoriasis and its treatment with latent human herpesvirus infection, we performed a cross-sectional study to determine if patients with severe psoriasis and psoriasis patients treated with immunosuppressive therapies have higher rates of Epstein-Barr virus and human herpesvirus 6 replication compared to healthy controls. The prevalence of Epstein-Barr virus and human herpesvirus 6 replication was measured in white blood cells by quantitative polymerase chain reaction. We found no evidence of active viral replication in white blood cells of healthy controls (0/10; 95% confidence interval 0-0.26), patients with severe psoriasis (0/25; 95% confidence interval 0-0.11) or severe psoriasis patients on immunosuppressive treatment (0/26; 95% confidence interval 0-0.11). The results of this study suggest that neither severe psoriasis alone, nor in combination with immunosuppressive therapy, is associated with an increase in Epstein-Barr virus or human herpesvirus 6 replication in white blood cells.