Rituximab reduces B cells and T cells in cerebrospinal fluid of multiple sclerosis patients

Abstract

Effects of B cell depletion by rituximab, a monoclonal antibody to CD20, were studied in patients with relapsing MS that had not responded optimally to standard immunomodulatory therapies. Flow cytometry demonstrated reduced cerebrospinal fluid (CSF) B cells and T cells in most patients at 6 months post-treatment. ELISAs demonstrated modest reductions in serum antibodies to myelin oligodendrocyte glycoprotein and myelin basic protein in some subjects. Beta-interferon neutralizing antibodies were reduced in three subjects, but developed anew after treatment in three others, suggesting caution in considering rituximab as a means to eliminate NABs. In summary, rituximab depleted B cells from CSF at 24 weeks after initial treatment, and this B cell depletion was associated with a reduction in CSF T cells as well.

Figures

Fig. 1

(A–D) Serum ELISA results for: (A) total Ig (IgG, IgM and IgA) and (B) IgM to human myelin oligodendrocyte glycoprotein, and (C) total Ig (IgG, IgM, IgA) and (D) IgM to human myelin basic protein. Each subject is identified by study number and represented by 2 bars, the first collected at week 0 (pre-rituximab — R) and the second at week 24 (post-rituximab — S). The post-treatment (S) sample on subject 012 was not obtained until 36 weeks post-treatment. For (A) and (B), samples were diluted 1:250 and 1:500, and antibody specific for rMOG was detected via ELISA vs. recombinant protein. Samples with an Abs450 nm greater than 0.1 (dotted line) were considered positive, based on results obtained with healthy donors. For (C) and (D), serum dilutions of 1:500 and 1:1000 were used. An Abs450 of ≥ 0.30 was set for positive total Ig to MBP due to lack of a consistent dilution effect below that absorbance.

Fig. 2

Results of CSF Immune analyses of CSF obtained prior to and 24 weeks after beginning rituximab therapy. (A) IgG concentration; (B) IgG synthesis rate; (C) IgG Index and (D) oligoclonal band number. The post-treatment sample on one patient (012) was not obtained until 9 months post-treatment.

Fig. 3

CSF concentration of lymphocytes pre- and post-rituximab therapy. Number of cells per ml of CSF for (A) B cells and (C) T cells determined on 20–25 ml CSF samples obtained at week 0 and week 24. (B and C) show the mean±S.E.M. for B and T cell numbers at weeks 0 and 24 after therapy. The post-treatment sample on one subject (012) was delayed until 9 months post-treatment. P-values derive from paired t-tests.

Fig. 4

Serial unblinded clinical assessments. Expanded disability status scores (EDSS) for the first 16 patients in this open-label trial.