CD4 and neoplasm: On the other hand, the activated fibroblastic reticular cell subset C13-CCL19+ FRCs following neoadjuvant chemotherapy (NACI) can establish extensive communication with CD4+ T cells, CD8+ T cells, and B cells through the CXCL12-CXCR4 axis, potentially playing a positive regulatory role in lymphocyte recruitment and anti-tumor immune responses (104).