ITIH4 and HIV infectious disease: We observed positive PLA between CD4 and ⍺4β7 on both subsets, however the frequency of measurable PLA on ⍺4β7high memory cells was ~2.5 greater than on naïve CD4+ T cells, indicating HIV gp120, like MAdCAM-1, can deliver costimulatory signals through ⍺4β7 in a way that promotes cellular proliferation and HIV infection [38,39].