Cytomegalovirus-seropositivity has a profound influence on the magnitude of major lymphoid subsets within healthy individuals


Professor P. Moss, Professor of Haematology, University of Birmingham, Edgbaston, Birmingham B15 2TA, UK.


Cytomegalovirus (CMV) infects most individuals and elicits a strong CMV-specific immune response. We have studied the influence of CMV-seropositivity on the size of lymphoid subsets in healthy donors and demonstrate that the virus substantially modulates the peripheral lymphoid pool. CD8+ T cell numbers are increased in all CMV-seropositive individuals because of a striking 60% increment in the CD8+ T cell memory pool. The CD45RA+ resting memory pool is doubled after CMV infection and increases further with age. The magnitude of the naïve CD8+ T cell pool is dramatically reduced in CMV-seropositive individuals at all ages, and this accelerates the physiological decline by approximately 40 years. The number of CD4+ effector memory T cells is increased in CMV-seropositive individuals and is differentially accommodated by a reduction in the number of naïve and central memory CD4+ T cells in young and elderly donors respectively. CMV-seropositivity also increases the total number of B cells in older donors and suppresses the number of CD5+ B cells. These data reveal that CMV has a profound influence on the immune system of all healthy individuals and add to growing concern regarding the clinical and immunomodulatory significance of CMV infection in healthy donors.