FTY720 leads to a rapid decrease of blood lymphocyte counts. We sampled blood 2 h after i.p. injection of FTY720 (1 mg/kg). FACS analysis showed a significant reduction of both CD4+ and to a lesser extent CD8+ T cells (n = 3/group). Statistical significance between groups was tested with two-tailed Student’s t-test for unpaired values. * p < 0.05.