The thymus is a source of B-cell-survival factors-APRIL and BAFF-in myasthenia gravis

Mathula Thangarajh1, Thomas Masterman, Lars Helgeland

  • 1Neurology Division, Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden. Mathula.Thangarajh@ki.se

The accumulation of B cells in the thymus is a common feature of myasthenia gravis (MG). To understand whether factors enhancing B-cell survival are increased in MG, we studied the expression of APRIL, BAFF and three of their receptors in the thymus. In hyperplastic thymi, macrophages expressed APRIL and BAFF, and germinal-center B cells, BAFF-R. CD138-positive plasma cells were abundant in MG thymi. By contrast, BCMA-positive plasma cells were scarce. The expression of APRIL and BAFF in MG thymi may reflect the establishment of an environment favorable to B-cell survival.

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