CXCR5 and HIV infectious disease: Therefore, we next examined the relationship between TFH and TFR within HIV infected tonsils, defining TFR as CD4+CXCR5+CD25+CD127low cells that are enriched for the TREG transcriptional factor FoxP3 (30) (Figure 4A), and having found that CD25 expression is not affect by HIV infection (Figure S3A).