In vivo stability of human chemokine and chemokine receptor expression

Cross-sectional analyses of human PBMC, plasma, and tissue have reported al tered chemokine and/or chemokine receptor expression in several inflammator y diseases. Interpretation of such studies is difficult without data on the in vivo stability of such parameters. Using four color flow cytometry, we longitudinally followed CXCR3, CCR5 (Th1-associated), and CCR3 (Th2-associa ted) expression within CD4(+)/CD45RO(+) and CD8(+)/CD45RO(+) T cell populat ions in peripheral blood of healthy individuals over a 21 day period. In pa rallel, we quantified plasma levels of IP-10, Mig, eotaxin and TARC. Chemok ine and receptor expression differed markedly between subjects but was high ly stable, varying by <5% within individuals. Differences in chemokine rece ptor expression between subjects were markedly altered when quantified as a bsolute cell numbers rather than frequencies. Finally, CCR3 expression by C D4(+)/CD45RO(+) T cells was positively correlated with plasma levels of its ligand, eotaxin, whereas strong negative correlations were evident between CXCR3 expression and IP-10 or Mig. These data demonstrate longitudinal sta bility of chemokine receptor and ligand expression among healthy individual s; reveal that both frequency and absolute cell count analysis is essential fur accurate assessment of chemokine receptor expression; and identify inv erse relationships between type 1 and type 2 immunity-associated receptors and their ligands in vivo. Human Immunology 62, 668-678 2001. (C) American Society for Histocompatability and Immunogenetics, 2001. Published by Elsev ier Science Inc.