In rheumatoid arthritis soluble CD30 ligand is present at high levels and induces apoptosis of CD30+T cells

• In RA high sCD30 reflects the attempt by CD30+T cells to downmodulate inflammation.
• Evaluation of sCD30 serum levels in RA may predict a good response to DMARDs.
• sCD30L is present at high levels in rheumatoid patients and is functionally active.
• Indeed it has the ability to bind CD30+T cells and to inhibit cell proliferation.
• sCD30L may correlate with disease activity and with lack of response to treatment.

CD30 and CD30 ligand (CD30L) are members of TNF-receptor and TNF superfamilies respectively. CD30+T cells are increased in several diseases and interaction between CD30+ and CD30L+T cells leads either to cell proliferation or apoptosis.In patients with rheumatoid arthritis (RA), soluble CD30 (sCD30) levels seem to reflect the recruitment of CD30+T cells into the inflamed joints and are predictive of a positive response to classical and biological immunosuppressive therapy. We have evaluated the presence of soluble CD30L (sCD30L) in the sera and synovial fluid of patients with RA and defined whether it binds surface CD30 molecule and is functionally active. We found high levels of sCD30L in sera and synovial fluid of RA patients; the molecule is shedded upon direct contact of CD30+/CD30L+T cells. Moreover sCD30L binds surface CD30 constitutively expressed by Jurkat cell line. Finally recombinant sCD30L and sera from patients with high levels of sCD30L are able to inhibit CD30+T cell proliferation by inducing cell apoptosis.Our findings suggest that circulant sCD30L is functionally active and that it may favor persistence of active inflammation by inducing apoptosis of CD30+T cells, known to down-modulate inflammation in rheumatoid synovitis.