SDC1 and neuromyelitis optica: Third, in a study of single CSF B cells from an early NMO patient, 3.7% of the CSF lymphocyte population was CD19+ CD138– B cells, and 0.9% were CD138+ ASCs; most of the CD138+ CSF ASCs (70.5%) were CD19+ CD138+ SLPBs, the rest were CD138+.CD19- LLPCs.