In the thymus of MG patients, CXCL13 is overexpressed by medullary TECs [17, 18, 19] and several indications suggest that CXCL13 could be involved in the infiltration of B cells: 1) thymic extracts from MG patients have a strong chemoattractive effect on B cells, 2) this effect is reduced when using anti-CXCL13 blocking antibodies and 3) the thymus of MG patients under corticotherapy shows a normalized level of CXCL13 together with a reduced number of GCs [17]. The gene discussed is CXCL13; the disease is myasthenia gravis.