Cutting edge: A role for B lymphocyte stimulator in systemic lupus erythematosus

Increased levels of B lymphocyte stimulator (BLyS) are associated with syst emic autoimmunity in animal models of spontaneous autoimmune disease, and t ransgenic animals expressing BLyS develop typical autoimmune disease. Here, we demonstrate significant elevations of BLyS in the patients with systemi c lupus erythematosus (SLE). The BLyS isolated from the sera of SLE patient s had the same m.w. as the natural soluble form and was able to stimulate B cell activation in vitro. Increased BLyS in SLE patients was partially ass ociated with higher levels of anti-dsDNA Ab of the IgG, IgM, and IgA classe s, but not associated with the disease activity. Our results suggest that B LyS may be a useful marker for early activation of an autoimmune diathesis and likely plays a critical role in triggering activation of self-hg-driven autoimmune B cells in human SLE. BLyS may provide an effective therapeutic target in systemic autoimmunity.