In PB samples, metastatic NB patients showed higher expression of IL-10 (2−ΔCt: 2.89 × 10−3 ± 4.66 × 10−3 versus 0.41 × 10−3 ± 0.56 × 10−3; P < 0.0001), ARG-1 (2−ΔCt: 20.21 × 10−3 ± 24.32 × 10−3 versus 4.54 × 10−3 ± 6.54 × 10−3; P < 0.0001), and CD163 (2−ΔCt: 45.2 × 10−3 ± 62.2 × 10−3 versus 13.5 × 10−3 ± 4.7 × 10−3; P = 0.02) mRNAs than healthy donors (Figure 1(b)). This evidence concerns the gene ARG1 and neuroblastoma.