SYK and rheumatoid arthritis: Due to its major role in B lymphocyte signaling, SYK signaling has been highlighted as a therapeutic target and has shown beneficial results in models of autoimmune diseases like rheumatoid arthritis, systemic lupus erythematosus, and thrombocytopenic purpura as well as in the treatment of B-cell malignancies (14, 24, –, 26, 64).