Blys

Synonym(s)

BAFF; B-cell activating factor; B-cell activation factor

Acronym for "soluble human B lymphocyte stimulator protein". BLyS is a naturally occurring protein that is essential for the maturation, survival and function of B lymphocytes. BLyS belongs to the tumor necrosis factor superfamily (see below tumor necrosis factor-α) and is membrane-bound and dissolved in its active form. BLyS is expressed on cells of the innate immune system, on neutrophil granulocytes, monocytes and macrophages; furthermore on dendritic cells and some T- and B-cells.
3 different receptors are currently detected on B cells: BLys receptor 1-3, with BLyS receptor 3 (BR3, syn. BAFFr) being the most important. The BLyS3 receptor performs a crucial function in antibody production by inhibition of selection and apoptosis of autoreactive B cells.
In SLE patients (see below lupus erythematosus, systemic) it has been shown that serum levels of BLyS are elevated and correlate with the concentration of double-stranded antibodies. It is assumed that in systemic lupus erythematosus and certain other autoimmune diseases, elevated BLyS levels contribute to the production of autoantibodies. Inhibition of BLyS by a monoclonal antibody ( Belimumab) led to an improvement in the clinical picture.

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