CXCL13 and AIDS: Fourth, the fact that differential levels of human and murine CXCL13 are readily seen in the model and are readily identifiable as being produced by tumor (human CXCL13) or non-tumor (murine CXCL13) cells, suggests that this model could have substantial potential utility for determining the source of other molecules that are known to be over-produced in persons who develop AIDS-lymphoma, such as soluble CD23 and IL-6 [30,31].