Inhibition of CD23 and L-selectin shedding by OxATP. B-CLL lymphocytes were treated with (○) or without (•) 300 μmol/L OxATP before exposure to 100 μmol/L BzATP. Expression of CD23 (A) and L-selectin (B) was measured and results expressed as the mean percentage of initial expression ±SEM (n = 3).