CD4 and infection: Gut-associated lymphoid tissue is a major anatomical site of HIV replication, CD4+ T cell depletion in acute and early infection, and a major site of HIV persistence on ART.27–31 Significantly increased 89Zr-VRC01 rSUVmean uptake was observed in both viremic and ART-suppressed individuals in various gut tissues as shown in Fig. 3.