The chemokine receptors CCR5 (C-C chemokine receptor type 5) and CXCR4 (C-X-C motif chemokine receptor 4), which are critical in HIV infection, have been seen in the microparticles released from PBMCs (peripheral blood mononuclear cells) or megakaryocytes. Here, CXCR4 is linked to HIV infectious disease.