title: VH3-21 B cells escape from a state of tolerance in rheumatoid arthritis and secrete rheumatoid factor.
abstract: BACKGROUND
  Rheumatoid factor (RF) is a characteristic but not pathognomic feature in patients with rheumatoid arthritis (RA). It is unknown whether the repertoire of immunoglobulin genes utilized by RF+ B cells of RA patients is unique and whether RF+ B cells in normal individuals are silenced or deleted.
  
  
  METHODS
  Clonal B cell populations were established from the peripheral blood of normal donors (127 B cell clones), RA patients (113 RF- and 60 RF+ B cell clones) and patients with primary Sjögren's syndrome (82 RF- and 47 RF+ B cell clones) by coculturing with anti-CD3-stimulated T helper cell clones. The cross-reactivity pattern of antibodies secreted by the B cell clones was determined by ELISA on a panel of antigens. The molecular structure of the IgM heavy chains was characterized by VH family-specific RT-PCR and sequencing. VH elements which correlated with RF specificity were identified. The responsiveness of B cells expressing these VH elements to T helper cell signals was compared in normal individuals and RA patients.
  
  
  RESULTS
  The majority of RF+ B cells were monospecific when specificity was tested on five antigens. RF+ B cells expressed a significantly different repertoire of VH gene segments than RF- B cells. In particular, the VH3 gene segment V3-21 was not detected in B cell clones from normals but was the most frequent VH element in RF+ B cell clones from RA patients. Most of the V3-21 sequences were in germline configuration. The correlation between RF specificity and V3-21 gene segment usage was maintained in patients with Sjögren's syndrome. V3-21 transcripts were present in peripheral blood B cells from normal individuals. VH3-21+ B cells from RA patients but not from normal donors were responsive to preactivated T helper cells. Stimulation with a bacterial superantigen could overcome the nonresponsiveness of V3-21+ B cells in normal donors and induce the secretion of RF.
  
  
  CONCLUSIONS
  RF production is correlated with the usage of the V3-21 gene segment in two distinct RF+ diseases. In patients with these diseases, V3-21+ B cells secrete antibodies with RF activity in response to activated T helper cells. V3-21+ B cells remain in a state of nonresponsiveness in normal individuals that can be broken by superantigen stimulation. The germline configuration of VH3-21+ RF+ immunoglobulins in RA patients suggests that the loss of tolerance is not an antigen-driven process.
authors.affiliation: Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota, USA.
authors.forename: X
authors.initials: X
authors.lastname: He
authors.forename: J J
authors.initials: JJ
authors.lastname: Goronzy
authors.forename: W
authors.initials: W
authors.lastname: Zhong
authors.forename: C
authors.initials: C
authors.lastname: Xie
authors.forename: C M
authors.initials: CM
authors.lastname: Weyand
mesh_terms: D000918:Antibody Specificity; D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D001483:Base Sequence; D017252:CD3 Complex / Q000276:immunology; D002999:Clone Cells; D003429:Cross Reactions; D006801:Humans; D007108:Immune Tolerance; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007075:Immunoglobulin M / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics; D008969:Molecular Sequence Data; D012217:Rheumatoid Factor / Q000378:metabolism*; D012859:Sjogren's Syndrome / Q000276:immunology; D018089:Superantigens / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D017252:CD3 Complex; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D018089:Superantigens; D012217:Rheumatoid Factor