CD4+CD25+Foxp3+ regulatory T (Treg) cells, known for their immunomodulatory functions, express C-X-C chemokine motif receptor 4 (CXCR4) and C-C chemokine receptor 5 (CCR5) coreceptors and support high levels of HIV infection and replication23. The gene discussed is CXCR4; the disease is HIV infectious disease.