CD4 and acute kidney injury: Neutrophils increased ~ threefold in KO versus WT animals after injury (Fig. 3B and E, 0.71 ± 0.11% of positive area per high power field in KO AKI vs. 0.24 ± 0.04% of that in WT AKI kidney), and CD4 + T cells increased ~ twofold in KO as compared to WT (Fig. 3C and E, 0.88 ± 0.11% of positive area per high power field in KO AKI kidney vs. 0.47 ± 0.01% positive area per high power field in WT AKI).