Fig 1: Soluble B-cell-related biomarkers corroborate robust and lasting depletion of blood B cells, but poor depletion of central nervous system B cells by rituximab (RTX) treatment. Concentration of serum and cerebrospinal fluid (CSF) B-cell activating factor (BAFF) (A), C-X-C motif chemokine 13 (CXCL13) (B), and soluble CD21 (sCD21) (C) were measured in coded samples (active-treatment cohort: n = 14, placebo cohort: n = 9; placebo data not shown) using electrochemiluminescence assay. Red lines show median values of biomarkers at each follow-up visit. Red and blue arrows show the timing of intravenous (IV) or intrathecal (IT) injection of RTX. Black brackets represent statistical significance (P < 0.05) based on adjusted P-value (Dunnett's method). Concentrations of BAFF, CXCL13, and sCD21 were compared between baseline (average of visit Months -12 and 0) and each follow-up visit (serum: Months 0.5, 0.53, 1.5, 1.53, 3, 12, and 12.03; CSF: Months 1.5, 3, and 12).