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woensdag 24 oktober 2012

High CD8+ and low CD57+, what does it mean?

The role of CD8+, CD57+ cells in human cytomegalovirus and other viral infections.

Source

Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff, UK.

Abstract

Peripheral blood lymphocytes expressing CD8 and CD57 determinants are a small (1-15%) subset in healthy humans. CD8+, CD57+ peripheral blood lymphocytes may be divided by the level of CD8 expression, into CD8+high (CD57+) T-cells and CD8+low (CD57+) natural killer (NK) cells. CD8+high (CD57+) T-cell numbers are increased in human cytomegalovirus (HCMV)-seropositive subjects, and there is substantial evidence that HCMV is integral in the development of this subset in health and disease. Furthermore, the CD8+high (CD57+) subset is clonally derived, expressing a limited range of T-cell receptors, and are therefore likely to have restricted antigen specificity. Functionally, CD8+low(CD57+) cells exhibit NK activity, while CD8+high(CD57+) T-cells from healthy subjects mediate contact-dependent suppression in several in vitro systems including: (i) pokeweed mitogen-induced proliferation and immunoglobulin synthesis, and (ii) generation of antiviral MHC-restricted cytotoxic T-lymphocytes. This is distinct from the nonspecific, soluble factor-mediated suppression exhibited from a phenotypically similar subset in human immunodeficiency virus (HIV) and bone marrow transplant recipients. This suggests an important immunoregulatory, suppressive role for CD8+high(CD57+) T-cells that may be potentiated by HCMV and altered in diseases associated with higher numbers of this subset including HIV, allograft recipients and rheumatoid arthritis.