Immunoglobulin subtypes predict therapy response to the biologics in patients with rheumatoid arthritis.

To analyze the effectiveness of rituximab (RTX) versus alternative TNF antagonists (aTNFs) on rheumatoid arthritis (RA) disease activity in different subgroups of patients and relation with extraarticular manifestations of RA and to assess that RF-subsets have potential as predictors of clinical response to RTX. Patients with RA (n = 40, M/F: 3/37) who received aTNFs at least 6 months with good response (group I; n = 20) or discontinued at least one aTNFs because of the ineffectiveness and subsequently received RTX at least one course (group II; n = 20) were retrospectively evaluated. IgM-, IgA-, IgG-rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) levels were measured by ELISA technique.