NAMPT is expressed by NLCs and by myeloid elements in CLL LNs. (A) Heat map showing gene expression profiling performed on conventionally differentiated NLCs (n = 10) highlighted elevated levels of genes classically associated with M2 macrophages, including NAMPT. Expression values are represented as Log2 of relative quantification (RQ) calculated as relative expression on ACTB housekeeping gene. (B-C) Box plot showing NAMPT mRNA expression levels (B) and eNAMPT soluble levels (C) in NLCs from CLL patients obtained using conventional culture conditions (n = 28) or differentiated in the presence of lenalidomide (n = 5). (D-E) NLC numbers (D) and morphology assessed by Giemsa staining (E) were determined in CLL samples differentiated with or without addition of rNAMPT. A blocking pAb anti-NAMPT or control preimmune goat serum were added to conventional NLC cultures to inhibit constitutive eNAMPT. Original magnification ×20 in panel E. (F-G) Immunohistochemical analysis of NAMPT expression in reactive (F) or CLL (G) LN. CD163 was used to detect macrophages in both normal tissues and CLL LN. Images at ×4 and ×20 original magnifications. The immunofluorescence image in panel F shows complete overlap between NAMPT (red) and CD163 (white) staining in reactive LN (magnification ×63). (H) Immunofluorescence images showing partial overlap between NAMPT staining (red) and CD163 (white) in CLL LN samples. Within the proliferation center, NAMPT shows partial colocalization with CD23⁺/Ki-67⁺ CLL lymphocytes. Original magnification ×63.