title: IL-4 down-regulates the surface expression of CD5 on B cells and inhibits spontaneous immunoglobulin and IgM-rheumatoid factor production in patients with rheumatoid arthritis.
abstract: There is evidence to suggest that CD5+ B cells may be associated with autoimmunity, e.g. they are increased in patients with rheumatoid arthritis (RA). In this study, we found that the expression of CD5 on RA B cells increased spontaneously, following culture for up to 4 days in vitro in the absence of T cells, supporting the idea that the CD5+ B cell possesses distinctive features. The spontaneous increase of CD5 expression was down-regulated by recombinant IL-4 (rIL-4). Other cytokines studied (rIL-1 alpha, rIL-2, rIL-5, rIL-6) did not alter CD5 expression. Studies of antibody production showed that rIL-4 could reduce spontaneous production of total IgG and IgM in non-stimulated RA T plus B cell cultures. Spontaneous production of IgM rheumatoid factor (IgM-RF), measured by a newly developed avidin-biotin complex ELISA, was also reduced by rIL-4. Furthermore, rIL-4 reduced the increase in IgM-RF production observed on stimulation with Staphylococcus aureus Cowan I (SAC) or pokeweed mitogen (PWM). Thus, IL-4 might act as a regulator of the development of abnormal B cell differentiation in patients with RA.
authors.affiliation: Internal Medicine I, National Defence Medical College, Saitama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hidaka
authors.forename: A
authors.initials: A
authors.lastname: Kitani
authors.forename: M
authors.initials: M
authors.lastname: Hara
authors.forename: M
authors.initials: M
authors.lastname: Harigai
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: T
authors.initials: T
authors.lastname: Ishizuka
authors.forename: M
authors.initials: M
authors.lastname: Kawagoe
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis*; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D018956:CD5 Antigens; D002478:Cells, Cultured; D015536:Down-Regulation; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007075:Immunoglobulin M / Q000096:biosynthesis*; D015847:Interleukin-4 / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D012217:Rheumatoid Factor / Q000096:biosynthesis*
chemical_list: D015703:Antigens, CD; D018956:CD5 Antigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015847:Interleukin-4; D012217:Rheumatoid Factor