RESULTS: A multiparametric PSN revealed that the combination of a low proportion of dendritic cells (cDC2s), HLA-DR+ natural killer (NK) cells, a high proportion of NK cells from lymphocytes, a higher percentage of CD88+ cDC1 cells, and neutrophil (NEU) immunophenotypes has demonstrated outstanding performance in detecting PJI, including low-grade PJI, comparing to sterile inflammation induced by wear particles. The gene discussed is C5AR1; the disease is juvenile polyposis syndrome.