title: Increased responsiveness of rheumatoid factor-producing B cells in seronegative and seropositive rheumatoid arthritis.
abstract: OBJECTIVE
  To compare the frequencies and responsiveness of rheumatoid factor (RF)-producing B cells in the peripheral blood of patients with seronegative and seropositive rheumatoid arthritis (RA).
  
  
  METHODS
  Frequencies of IgM+, IgG+, and RF+ B cells were determined by limiting-dilution analysis of purified peripheral blood B cells from 6 patients with seropositive RA, 8 patients with seronegative RA, and 7 normal controls. B cell help was provided by cloned T helper cells, which were stimulated by either anti-CD3 or the bacterial superantigen staphylococcal enterotoxin D (SED). IgM and IgG antibodies and RF in culture supernatants were detected by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  In the presence of anti-CD3-stimulated T helper cells, 2-10% of B cells from normal individuals secreted IgM and IgG antibodies. The frequency of RF+ B cells was low and ranged from 1:182 to 1:885 (RF+: IgM+) B cells. In patients with seropositive RA, the numbers of Ig-producing B cells were reduced by a factor of 2, while the fraction of RF+ B cell precursors was expanded by more than 50-fold (7-20% of IgM+ B cells; P = 0.004). Patients with seronegative RA had higher frequencies of RF-producing B cells (1.5-6% of IgM+ B cells) than normal individuals (P = 0.002), but not to the same extent as seropositive patients (P = 0.002). Stimulation of B cells using SED preferentially induced RF+ B cells in normal controls and in patients with seronegative and seropositive RA.
  
  
  CONCLUSIONS
  B cell precursors with the potential to secrete RF were detectable in high frequencies in normal individuals and in patients with seropositive and seronegative RA. In all donors, these B cells could be stimulated with the bacterial superantigen SED. In normal individuals, RF+ B cells remained nonresponsive to help provided by anti-CD3-activated T cells, but were responsive in RA patients. Seronegative and seropositive RA form a continuous spectrum of disease, with a higher number of RF-secreting B cells in the seropositive patients.
authors.affiliation: Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: X
authors.initials: X
authors.lastname: He
authors.forename: W
authors.initials: W
authors.lastname: Zhong
authors.forename: T G
authors.initials: TG
authors.lastname: McCarthy
authors.forename: C M
authors.initials: CM
authors.lastname: Weyand
authors.forename: J J
authors.initials: JJ
authors.lastname: Goronzy
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000145:classification / Q000276:immunology*; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D017252:CD3 Complex; D002478:Cells, Cultured; D004768:Enterotoxins / Q000494:pharmacology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D007075:Immunoglobulin M / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012217:Rheumatoid Factor / Q000378:metabolism*; D006377:T-Lymphocytes, Helper-Inducer
chemical_list: D017252:CD3 Complex; D004768:Enterotoxins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C019368:enterotoxin D, Staphylococcal; D012217:Rheumatoid Factor