Consistent with these results, confocal microscopy studies demonstrated that FDCs retain infectious HIV-1 in cycling endosomes through the complement receptor CD21 (Heesters et al., 2015) and multispectral flow cytometry (ImageStream) showed in vitro infection of macrophages via selective capture of HIV-1-infected CD4+ T cells (Baxter et al., 2014). The gene discussed is CD4; the disease is infection.