Rheumatoid Arthritis Support

Three membrane receptors are concerned:

* BCMA (B cell maturation antigen)

* TACI (transmembrane activator and calcium modulator and cyclophylin ligand interactor)

* BAFF-R (also known as BR3)

These receptors are not present in early B cell precursors or in pre-B cells (stage at which CD20 receptors appear). They are present in primary mature B cells and in mature B cells (in this last stage, CD20 receptors have disappeared).

BLyS is secreted, sometimes under the influence of interferon-gamma, by a variety of cells: monocytes and macrophages, bone marrow stromal cells, astrocytes, synoviocytes during rheumatoid arthritis, salivary epithelial cells during Sjögren's syndrome, astrocytes in certain glioblastomas.

Lymphocyte apoptosis may be decreased by BLyS because stimulation of BAFF-R and BCMA increases levels of Bcl-2, which is a key anti-apoptotic mediator. Stimulation of all 3 BLyS receptors increases intranuclear levels of NF kappa B, active on differentiation and proliferation.

BLyS is not the only activator of B lymphocytes. APRIL (a proliferation activating ligand) also plays a key role, but is only active on BCMA and TACI.


Adapted from the Wikipedia article Belimumab, under the G. N. U. Free Documentation License. Please also see http://en.wikipedia.org/wiki