tokens: The serum level of the shed form of L-selectin was significantly increased in ATL patients ( mean +/- SD , 4 , 215.4 +/- 4 , 111 ng/mL ) compared with those of asymptomatic carriers and healthy blood donors ( mean +/- SD , 1 , 148.0 +/- 269.0 ng/mL and 991.9 +/- 224 ng/mL , respectively ) .