The B cell repertoire of patients with rheumatoid arthritis. Frequencies and specificities of peripheral blood B cells reacting with human IgG, human collagens, a mycobacterial heat shock protein and other antigens

Abstract

SUMMARY Using a potent in vitro limiting dilution culture system, we have activated human peripheral blood B cells to proliferate and to differentiate into antibody‐secreting cells (ASC). Under these conditions 25–100 % of B cells are clonally expanded and produce IgM, IgG or IgA. Culture supernatants were tested for antibodies binding to human IgG‐Fc fragments (RF), the 65‐kD heat shock protein of Mycobacterium bavis (hsp60), human collagens type I, II, IV, V, transferrin, lactoferrin, albumins, and gelatine. All blood samples contained precursors of ASC (p‐ASC) able to produce IgM binding to these antigens in frequencies above 003% of B cells. Most interestingly, a significant difference exists between rheumatoid arthritis (RA) patients and controls, concerning the relative frequencies of p‐ASC able to produce monospecific or multircactive RF. Whereas most p‐ASC(RF) in RA patients are monospecific (mean ratio 3.7), most p‐ASC(RF) in healthy control persons are cross‐reactive with at least one of five other antigens tested (mean ratio 0.2). The data suggest a disease‐specific expansion of p‐ASC committed to the production of monospecific rheumatoid factors.

Precursor frequencies for DNA-specific B lymphocytes in patients with systemic lupus erythematosus (SLE)

“…elevated erythrocyte sedimentation rate (> 30 mm/h) and decreased activity of complement{determinedasCH5() <20U/mIandC3d > 10/jg/dl) [16], Seven patients (nos 1-7) with only one clinical criterion and normal complement activity were included in the inactive group. Thirteen patients (nos [8][9][10][11][12][13][14][15][16][17][18][19][20] with two or more clinical criteria of aetivity and decreased complement activity were categorized as active. At the time of blood sampling, all patients were receiving corticosteroids (prednisone 10 40 mg/ day).…”

“…Peripheral B lymphocytes from 18 SLE patients and six healthy donors (HD) were polyclonally activated in the LD system described before [13,14]. Compared with B cells derived from HD, B cells from SLE patients were less efficiently activated, especially if they were derived from patients with inactive disease ( Table 1).…”

“…The culture medium consisting of RPMI 1640 (Biochrom Seromed, Berlin, Germany) supplemented with 10% heat-inactivated FCS (a selected batch; Biochrom Seromed), 2 mM L-glutamine and 5 x 10-5mmm 2-mercaptoethanol (Merck, Darmstadt, Germany). T cell/macrophage supernatants were prepared as described [13,14]. The Fig.…”

“…As B cells in this LD system are induced to switch from IgM to IgG production [13,14], we studied the coexistence of IgM and IgG in cultures, which statistically are expected to be of clonal origin [19]. (Table 2).…”

“…To study further the autoreactive B cell repertoire of SLE patients and healthy controls, we used a limiting dilution (LD) system, in which almost all B cells are activated and generate clones of antibody-secreting cells [13,14]. We estimated the frequencies of precursor cells for anti-DNA production and studied their specificity at the clonal level.…”