As we have recently shown that the number of CCR5 molecules at the cell surface determines the efficiency of its function as a chemokine receptor, we tested the hypothesis that cell surface CCR5 density could influence the intensity of T lymphocyte recruitment into the rheumatoid joint. For this purpose, we established two Jurkat cell line-derived clones that differed only by their cell surface CCR5 densities. We studied their chemotaxis towards TNF-alpha-transduced rheumatoid synoviocytes supernatant. The Jurkat cell subline that expressed the higher cell surface CCR5 density migrated more intensively towards the supernatant of TNF-alpha-transduced synoviocytes than the Jurkat cell subline that expressed a lower surface CCR5 density. Moreover, this migration was blocked by an anti-CCR5 mAb. The CCR5 density on T cell surface, which is constant over time for a given individual, but varies drastically from one individual to another, might thus be a factor determining the intensity of joint inflammation in the course of RA.