Effect of rituximab on circulating and synovial autoantibodies and immunoglobulin. (a) Circulating levels of autoantibodies and total IgM and IgG 8 weeks after rituximab treatment are expressed as percentage of pretreatment levels. (b) Serum-normalized levels of autoantibodies and total IgM and IgG determined by enzyme-linked immunosorbent assay, or mRNA levels of IgM and IgG1 heavy constant region determined by quantitative real-time polymerase chain reaction, in synovial biopsies 8 weeks after rituximab treatment are expressed as percentage of pretreatment levels. Data are expressed as geometric mean ± 95% confidence interval (CI) of 14 subjects. Asterisks denote that 95% CI excludes 0% change (stippled line). anti-CCP, anti-cyclic citrullinated peptide; RF-IgM, rheumatoid factor of the IgM subtype.