Importantly, only the NOS monocytes, MPO+ neutrophils, CD14+ classical monocytes and FcγRIII+ nonclassical monocytes significantly correlated with inflammation severity (Spearman correlation, P = 0.0002, P = 0.0072, P = 0.0094 and P = 0.0175 respectively, Fig. 4b, c), highlighting the relevance of these innate immune cells in kidney transplant rejection. This evidence concerns the gene MPO and kidney transplant.