 The gene for CXCL13 is located on human chromosome 4 in a cluster of other CXC chemokines.In T lymphocytes, CXCL13 expression is thought to reflect a germinal center origin of the T cell, particularly a subset of T cells called follicular B helper T cells (or TFH cells).Hence, expression of CXCL13 in T-cell lymphomas, such as Angioimmunoblastic T-cell Lymphoma, is thought to reflect a germinal center origin of the neoplastic T-cells.