Depletion of CD4⁺ T cells by chemoradiotherapy leads to depletion of FRC and FDC networks in cancer patients. (A) Immunohistochemical staining of CD4, CD35, and desmin in LNs from chemoradiotherapy-treated patients and untreated patients, showing the depletion of CD4 T cells in B-cell follicles and T-cell zone correlates with depletion of FDCs and FRCs. Dotted circles represent the position of B-cell follicles. Original magnification ×200. (B) Quantitative image analysis of the number of CD4 T cells (top panel) and amount of stromal cells (middle panel) within LNs of chemoradiotherapy-treated patients and untreated patients, showing that both CD4 T cells and stromal cells are depleted during chemoradiotherapy. The depletion of CD4 T cells significantly correlates with the depletion of stromal cells within chemoradiotherapy-treated patients.