ROC analysis
In the CIS-RRMS group, ROC analysis identified both CXCL13 (AUC = 0.959)
and IL-8 (AUC = 0.939) in cerebrospinal fluid (CSF) as significant
predictors for the conversion from clinically isolated syndrome (CIS) to
relapsing-remitting multiple sclerosis (RRMS).
The optimal cut-off value for IL-8 in CSF was determined to be 45.6
pg/ml, as calculated by the Youden’s J statistic, which maximizes the
sum of sensitivity (0.9) and specificity (0.836). For CXCL13 in CSF, the
optimal cut-off value was 0.210 pg/ml, also determined by Youden’s J
statistic, with sensitivity of 0.95 and specificity of 0.873. This test
showed higher sensitivity. Alternatively, if a higher cut-off value
(1.795) were selected, both sensitivity and specificity would be more
balanced, both approximately at 0.9, with SE = 0.900 and SP = 0.909. The
data are summarized in the Figure 4 and depicted in the