Elevated levels and functional capacity of soluble CD40 ligand in systemic lupus erythematosus sera

Arthritis Rheum. 1999 May;42(5):871-81. doi: 10.1002/1529-0131(199905)42:5<871::AID-ANR5>3.0.CO;2-J.


Objective: To measure soluble CD40 ligand (sCD40L) in sera from patients with systemic lupus erythematosus (SLE) and to study the functional capacity of sCD40L in mediating B cell activation.

Methods: A 2-site enzyme-linked immunosorbent assay (ELISA) was used to measure sCD40L in the sera of 66 SLE patients, 30 disease control patients, and 23 healthy subjects. Induction of B cell activation antigen expression was used to assess the functional capacity of sCD40L in SLE sera.

Results: The mean concentration of sCD40L was statistically significantly higher (P < 0.0001) in SLE patients than in disease controls or healthy subjects, and segregation of SLE patients by severe, moderate, or mild extent of disease showed a relationship between disease severity and sCD40L concentration. Western blot analysis demonstrated the presence of the 18-kd band of sCD40L in SLE sera, and the results of a 1-site ELISA protocol suggested that some of the product in SLE sera was present in dimer or trimer form. Functional studies showed that 10 ng/ml of recombinant CD40L, a level present in some SLE sera, induced increased expression of CD95 on B cells. Several SLE sera also induced CD95 or CD86 on Ramos B cells, a result that was inhibited by anti-CD40L monoclonal antibodies.

Conclusion: The soluble form of CD40L is present in the sera of most patients with SLE and may have the capacity to mediate B cell activation. Aberrant expression of CD40L might be predicted to result in activation of bystander B cells, including those that have encountered self antigens, and to contribute to autoantibody secretion.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antigens, Surface / biosynthesis
  • Arthritis, Rheumatoid / blood
  • B-Lymphocytes / immunology
  • CD40 Antigens / blood
  • CD40 Antigens / chemistry
  • CD40 Ligand
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Ligands
  • Lupus Erythematosus, Systemic / blood*
  • Membrane Glycoproteins / blood*
  • Membrane Glycoproteins / pharmacology
  • Molecular Weight
  • Recombinant Proteins / pharmacology
  • Solubility


  • Antigens, Surface
  • CD40 Antigens
  • Ligands
  • Membrane Glycoproteins
  • Recombinant Proteins
  • CD40 Ligand