Figure 2. (A) Quantification of YKL40 protein levels in the CSF in sALS (n=85) and control (n=23) cases. (B) ROC curves for YKL-40 quantification in the differential diagnosis of sALS compared to control cases. In the legend, AUC values, corresponding to the area under ROC curves, and 95% confidence intervals are reported. (C) Positive correlation between ALS-FRS-R slope (point/month) and YKL40 levels (pg/mL) (Pearson’s correlation, P=0.000). (D) Higher YKL40 protein levels in the CSF are found in cases with short survival (fast progression: FP) when compared with cases with slow and normal progression (SP and NP, respectively; P = 0.008, P = 0.004). (E) CHI3L1 mRNA expression levels in whole-blood samples of sALS and control cases. CHI3L1 is not deregulated in sALS.