Human serous cavity macrophages and dendritic cells possess counterparts in the mouse with a distinct distribution between species

In mouse peritoneal and other serous cavities, the transcription factor Gata6 drives the identity of the major cavity resident population of macrophages, with a smaller subset of cavity-resident macrophages dependent on the transcription factor Irf4. Here we showed that GATA6+ macrophages in the human peritoneum were rare, regardless of age. Instead, more human peritoneal macrophages aligned with mouse CD206+ LYVE1+ cavity macrophages that represent a differentiation stage just preceding expression of Gata6. Low abundance of CD206+ macrophages was retained in C57BL/6J mice fed a high-fat diet or in wild-captured mice, suggesting that differences between serous cavity-resident macrophages in humans and mice were not environmental. Irf4-dependent mouse serous cavity macrophages aligned closely with human CD1c+CD14+CD64+ peritoneal cells that, in turn, resembled human peritoneal CD1c+CD14-CD64- cDC2. Thus, major populations of serous cavity-resident mononuclear phagocytes in humans and mice shared common features but the proportions of different macrophage differentiation stages greatly differ between the two species and DC2-like cells were especially prominent in humans. Peritoneal wash was collected at the beginning of the procedure before it was affected by the surgical process. Patients recruited including those receiving laparoscopic surgeries including Roux-en-Y gastric bypass (RYGB) surgery, sleeve gastrectomy, gastrostomy tube placement, cholecystectomy, or inguinal hernia repair without any other clinical indication of peritoneal pathological conditions. Live CD45+ immune cells were sorted for sequencing >>>Raw data are being deposited in dbGaP due to patient privacy concerns<<<