CD4 and lymphopenia: FTY720 treatment also led to lymphopenia and affected both the percentage of total lymphocytes (69.98 ± 1.182% to 44.77 ± 1.320, P < 0.001) and CD4 cells (26.40 ± 1.895% to 13.70 ± 0.6234, P < 0.001) in the spleen.