We thus investigated the effect of a CXCR4 antagonist, AMD3100, and sCD4 on CCL21-induced migration using a CD4- and CXCR4-expressing H9 human T-lymphoma cell line; this cell line showed enhanced CCL21- or CCL19-dependent chemotaxis in the presence of gp120 at a comparable level to that observed in primary human CD4 T cells (data not shown). The gene discussed is CXCR4; the disease is lymphoma.