SSB and peeling skin syndrome: Additionally, elevated levels of B-lymphocyte stimulator (BLyS, also known as B cell activating factor [BAFF], which promotes B cell maturation, proliferation, and survival) are found in the serum and saliva of patients with pSS, with serum BLyS levels correlating with markers of disease activity, including salivary gland B cell clonal expansion, lymphoproliferation, and pSS-associated autoantibodies (anti–Ro/SS-A, anti–La/SS-B), IgG, and rheumatoid factor (RF) (5–8).