Development of quantitative analysis from immunofluorescence assay. Serum from diverse patients were used as primary antibody in an immunofluorescence assay (A). Quantification of fluorescence resulted from the densitometric analysis of fluorescence intensity using the NIH ImageJ software taking in account the fluorescent area (B). C+, corresponds to a positive control serum in which NMO-IgG antibodies had previously been confirmed, and C-, corresponds to a negative control serum in which the antibodies were absent. Sera from different patients appear indicated with an identifying reference number. Significant differences (* p ≤ 0.05 and ** p ≤ 0.01) with respect to C- serum are indicated. Error bars are ± SEM (n = 5).