Persistent CMV infection correlates with disease activity and dominates the phenotype of peripheral CD8+ T cells in psoriasis

: Background: Previously, we have reported a frequent association of active plaque psoriasis with inflammation‐mediated cytomegalovirus (CMV) reactivation. Objectives: This study aimed at characterizing the impact of CMV infection on psoriasis disease activity and peripheral cellular adaptive immune response. Patients/Methods: Twenty nine patients with active plaque psoriasis and 29 healthy controls were analysed for CMV‐serostatus, CMV‐antigenaemia, frequencies of peripheral CMV‐specific T cells and the immunophenotype of peripheral CD8+ T cells. Results: (i) Psoriasis severity was higher in CMV‐seropositive patients and positively correlated to the severity of CMV‐antigenaemia. (ii) In comparison to CMV‐seropositive healthy controls, CMV‐seropositive psoriasis patients showed a reduced frequency of circulating CMV‐specific T cells that increased under effective antipsoriatic therapy. (iii) The immunophenotype of peripheral CD8+ T cells was dominated by CMV‐seroprevalence. (iv) Selective analysis of CMV‐seronegative psoriasis patients revealed a strong expansion of a – probably early activated – CD8+ T‐cell population with the yet undescribed differentiation phenotype ‘CD45RA‐dim/CD11a‐dim’. Under effective antipsoriatic therapy this population decreased in parallel to an increase of effector differentiated CD8+ T cells. Conclusions: Taken together with our previous results of inflammation‐mediated CMV reactivation in psoriasis, our data support the concept of an interactive relationship between psoriasis and CMV infection which may be mediated by peripheral CD8+ T cells.