Reversible expression of CD4, CCR5, and CXCR4.

Sorted CD3⁻/CD4⁺/CD117⁺ in vivo differentiated MCs/basophils from 3 patients with asthma were placed in culture for up to 35 days to assess whether or not these cells can alter their expression of CD4, CCR5, and CXCR4 ex vivo. At each time point, cells were stained with antitryptase IgG and then with either anti-CD4 (A), anti-CCR5 (B), or anti-CXCR4 (C) IgG. The hatched bars indicate the percentage of tryptase⁺ cells (mean ± SD) that fail to express CD4 or one of the chemokine receptors. The solid bars indicate the percentage of tryptase⁺ cells that continue to express CD4, CCR5, and CXCR4. Note that none of the tryptase⁺ cells in the 35-day cultures expressed CD4, CCR5, or CXCR4. Similar findings were obtained when the double-stained cells were first incubated with either antichymase or anti-TMT IgG (data not shown).