CORRECTION
Haas M, Verhave JC, Liu ZH, Alpers CE, Barratt J, et al.: A Multicenter Study of the Predictive Value of Crescents in IgA Nephropathy. J Am Soc Nephrol 28: 691–701, 2017. As originally written and published, the abstract of this paper is unclear as to whether a biopsy showing crescents in exactly 25% of glomeruli should be classified as C1 or C2; it should be C2. Thus, the last sentence of the abstract should correctly read:
We propose adding the following crescent scores to the Oxford Classification: C0 (no crescents); C1 (crescents in less than one fourth of glomeruli), identifying patients at increased risk of poor outcome without immunosuppression; and C2 (crescents in one fourth or more of glomeruli), identifying patients at even greater risk of progression, even with immunosuppression.