Autostimulatory effects of IL-6 on excessive B cell differentiation in patients with systemic lupus erythematosus: analysis of IL-6 production and IL-6R expression

Clin Exp Immunol. 1992 Apr;88(1):75-83. doi: 10.1111/j.1365-2249.1992.tb03042.x.


Introducing avidin-biotin complex ELISA for anti-DNA antibody, the mechanism of in vitro production of anti-ssDNA antibody as well as of polyclonal immunoglobulin mediated by an IL-6-IL-6R loop was studied in patients with systemic lupus erythematosus (SLE). Regardless of the presence or absence of T cells, B cells from SLE patients could produce IgG anti-ssDNA antibody as well as total IgG without any stimulation. Low density B cells obtained by Percoll gradient density centrifugation responded to rIL-6 to produce IgG and IgG anti-ssDNA antibody. rIL-2 and rIL-4 had lesser effects on the differentiation of low density B cells. In fact, IL-6R was preferentially expressed on low density B cells from active SLE patients, as detected by anti-IL-6R MoAb, MT18, which did not inhibit IL-6 binding. SLE B cells, especially high density B cells, produced greater amounts of IL-6 in culture supernatants than did T cells, regardless of whether disease was active or inactive. Normal T cells and B cells did not produce significant amounts of IL-6. Thus, endogenous IL-6 produced by high density B cells bound to the IL-6R preferentially expressed on the low density B cells, and drove them into terminal differentiation, especially in active SLE patients. Further, addition of polyclonal anti-IL-6 or anti-IL-6R MoAb (PM1), which inhibited IL-6 binding, both inhibited IgG anti-ssDNA antibody as well as total IgG production by SLE B cells in a dose-dependent manner. These results suggest that interruption of the autocrine IL-6 loop would be of therapeutic value in SLE.

MeSH terms

  • Antibodies, Antinuclear / biosynthesis
  • Antibodies, Monoclonal / immunology
  • B-Lymphocytes / drug effects
  • B-Lymphocytes / metabolism*
  • Cell Differentiation / drug effects
  • DNA, Single-Stranded / immunology
  • Humans
  • Immunoglobulin G / biosynthesis
  • In Vitro Techniques
  • Interleukin-2 / pharmacology
  • Interleukin-6 / biosynthesis*
  • Interleukin-6 / pharmacology
  • Lupus Erythematosus, Systemic / immunology*
  • Receptors, Immunologic / analysis*
  • Receptors, Interleukin-6
  • Recombinant Proteins / pharmacology
  • T-Lymphocytes / metabolism


  • Antibodies, Antinuclear
  • Antibodies, Monoclonal
  • DNA, Single-Stranded
  • Immunoglobulin G
  • Interleukin-2
  • Interleukin-6
  • Receptors, Immunologic
  • Receptors, Interleukin-6
  • Recombinant Proteins