Expression of CD4, CCR5, and CD45RO cells in neonatal tissue determined by triple immunohistochemical staining for CD4, CCR5, and CD45RO visualized with spectral imaging and at higher magnification. The first column shows immunohistochemistry light microscopy. The following columns show the same cubes analyzed with Nuance software for spectral imaging. These analyses indicated more CD4⁺CCR5⁺ and CD4⁺CD45RO⁺ T cells (yellow) in the gut epithelium (A) and gut lymphoid aggregates (B) of newborn infants than in lymph nodes (C) or spleen (D). Scale bar indicates 0.1 mm. Data are representative of patients 1-10 included in our study.