A high prevalence of cytomegalovirus antigenaemia in patients with moderate to severe chronic plaque psoriasis: an association with systemic tumour necrosis factor alpha overexpression

Microbiological aspects are considered to be of pathophysiological importan ce in psoriasis, but there has so far been no information regarding cytomeg alovirus (CMV) infection. This is of interest, due to the high prevalence o f latent infection in the general population, the frequent reactivation in inflammatory diseases, and the immunomodulating capacity of CMV; To detect active infection we analysed CMV antigen expression of peripheral blood mon onuclear cells (PBMC) from psoriatic patients (n = 30) in comparison with h ealthy volunteers (n = 65), Using three monoclonal antibodies and immunocyt ological staining (alkaline phosphatase-antialkaline phosphatase technique) , we frequently found CMV antigenaemia in psoriasis (43 %) compared with he althy laboratory staff (12%, P < 0.01) and blood donors (6%, P < 0.001), Cl earance of CMV antigenaemia was observed with antipsoriatic treatment. CMV antigenaemia was symptomless, and was associated with seropositivity for an ti-CMV IgG but not IgM antibodies, indicating subclinical activation of lat ent infection. Serological investigations in 85 psoriatic patients gave no evidence for a higher prevalence of latent CMV infection. In psoriatic lesi ons, CMV DNA was only rarely detected by polymerase chain reaction. As it h as been shown that tumour necrosis factor (TNF)-alpha can induce CMV reacti vation, we determined TNF-or plasma concentrations and mRNA expression in P BMC from psoriatic patients. Elevated TNF-alpha levels were found and corre lated with the frequency of CMV antigen-expressing PBMC, suggesting a criti cal role of TNF-alpha, in CMV activation, We speculate that active, subclin ical CMV infection may be of pathophysiological importance in psoriasis.