In the response letter by Arbab et al entitled "Ferideprotaminesulfate labeling does not alter differentiation of mesenchymalstem cells," which appeared in the November 15, 2004, issueof
Blood (Volume 104:3412-3413),
the title's first word wasincorrect. The title should read "Ferumoxideprotaminesulfate labeling does not alter differentiation of mesenchymalstem cells."