Distribution of AQP4 antibody values in 46 comparison samples. (A) Correlation of the results between the semiquantitative titer of the cell-based indirect immunofluorescence assay (CIIFA) and the quantitative value derived from the fluorescence immunoprecipitation assay (FIPA) based on arbitrary fluorescence units (FU). (B) Titers of AQP4 antibody measured by CIIFA in sera of patients with various diseases.

Abbreviations: MS, multiple sclerosis; NMO, neuromyelitis optica; OND, other neurological diseases.