Figure 4.

Primary cultured human thymic epithelial cells (TECs) express cytokines and chemokines. Comparison of mRNA levels of interleukin 6 (IL-6) (A), tumor growth factor-β (TGF-β) (B), CCL21 (C), and CCL19 (D) in different thymic cell types. mRNAs were analyzed by real-time PCR and normalized to GAPDH. For each gene, mRNA expressions in primary TECs were normalized to 100 and compared with others cell types. mRNA expression levels are expressed as arbitrary units and are the mean values (n > 6 for thymuses and n > 4 different donors for primary cultured TECs (day 7), fibroblasts or thymocytes). p Values were obtained using the Mann–Whitney test. Asterisks indicate significant differences (*p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001).