CXCR3 and infection: We were unable to measure HIV-specific responses in these samples due to the low cell number and early infection stage, but HIV-specific Tfh and B cells may be measured in future studies of lymph node biopsies from participants in S4-5 of AHI, as we have shown here that there are significant increases in proliferation of CXCR3+ Tfh and B cells in these stages.