Rebuttal TO THE EDITORWe read with interest the letter of Kounis et al. questioning the possible role of nickel allergy in mediating adverse events in patients with jailed side branches in the SPIRIT III study [1]. This topic has been a subject of considerable notoriety since the relationship between cutaneous allergic reactions to nickel first incited the suggestion for vascular allergic reactions to nickel-containing products contributing to stent thrombosis or restenosis. The authors are correct that the first generation paclitaxel-eluting and sirolimuseluting stents with a stainless steel stent (316L) backbone have relatively high nickel content (14% by weight) [2]. However, the author's assertion that second-generation cobalt chromium stent do not contain nickel is incorrect. L605, the cobalt chromium alloy in the everolimus-eluting Xience V/Promus drug-eluting stent has a nickel content of 10% by weight [3], and the MP35N cobalt chromium alloy of the zotarolimus-eluting endeavor drug-eluting stent has a nickel content of 35% by weight [4]. In this regard, it is worthwhile to note that animal studies evaluating the vascular responses to these two drug-eluting cobalt chromium stents have shown less inflammation than those with a 316L stainless steel backbone [5][6][7]. Because the nickel content in these two newer drug-eluting stents vary widely, the reasons(s) for their reduced inflammatory response remains to be clarified, but likely is multifactorial, due possibly to thinner stent struts, lower drug dosing, and most importantly use of less inflammatory polymers.