Quantification of CD4⁺CCR5⁺ cells, CD4⁺CD45RO⁺ cells, and CD4⁺CD45RO⁺CCR5⁺ cells in neonatal tissue and cord blood. Data are derived from spectral imaging analyses of triple immunohistochemical stainings and flow cytometry. The graphs show mean percentages ± SEM of CD4⁺CCR5⁺ (A), CD4⁺CD45RO⁺ (B), and CD4⁺CD45RO⁺CCR5⁺ (C) cells. Percentages of CCR5⁺, CD45RO, and triple-positive CD4⁺ T cells in various tissues all differed significantly from those of CD4⁺ T cells in cord blood (P < .001 by Student t test). CD4⁺ T cells from gut epithelium and gut lymphoid aggregates (LA) expressed significantly more CCR5 and CD45RO than CD4⁺ T cells derived from lymph nodes (P < .01 and P = .05, respectively).