George A, Pushkaran S, Konstantinidis DG, et al. Erythrocyte NADPH oxidase activity modulated by Rac GTPases, PKC, and plasma cytokines contributes to oxidative stress in sickle cell disease. Blood. 2013;121(11):2099-2107.

On page 2100 in the 14 March 2013 issue, there is an error concerning 2 red blood cell densities. The fifth and sixth densities reported, “1.010 and 1.015 g/mL,” but should have read, “1.10 and 1.15 g/mL.” In “Methods,” the first sentence of the second paragraph under “RBC collection and density fractionation” reads, “For the experiments using fractionated RBC, whole blood was layered onto Optiprep density gradient medium (Sigma-Aldrich, St. Louis, MO) diluted from stock solution in PBS following the manufacturer’s instructions to obtain gradient layers with densities of 1.075, 1.085, 1.090, 1.095, 1.010, and 1.015 g/mL (fractions 1 to 6, respectively).” The sentence should have read, “For the experiments using fractioned RBC, whole blood was layered onto Optiprep density gradient medium (Sigma-Aldrich, St. Louis, MO) diluted from stock solution in PBS following the manufacturer’s instructions to obtain gradient layers with densities of 1.075, 1.085, 1.090, 1.095, 1.10, and 1.15 g/mL (fractions 1 to 6, respectively).”