WT BALB/c (A, D, G and J), CD40 KO (B, E, H, and K) and CD4 KO (C, F, I and L) mice were randomly assigned to either L5Tx or sham groups. Lumbar spinal cords were collected before surgery (naïve; i.e. “Day 0” in the graph), and days 1, 3, 7, 14, and 21 after surgery. RNA expression of chemokines, CCL2 (A–C), CCL3 (D–F), CCL5 (G–I), and CXCL1 (J–L) within these spinal cord samples were determined via real-time qRT-PCR using GAPDH as control. Percentage changes of each chemokines following surgeries within each genotype of mice (naive = 100%) were calculated and presented here. Data are presented as mean ± SEM (WT n = 4, CD40 KO n = 4, and CD4 KO n = 2–4). # p < 0.1 and ## p < 0.05 compared to corresponding naïve group; and * p < 0.1, and ** p < 0.05 compared to corresponding sham group.