Circulating CD14(+)CD163(+)CD206(+) M2 Monocytes Are Increased in Patients with Early Stage of Idiopathic Membranous Nephropathy

AIM: To analyze changes in peripheral blood monocytes and their clinical significance in patients with early stage of idiopathic membranous nephropathy (IMN). METHODS: A total of 27 patients with early stage of IMN and 16 age- and sex-matched healthy controls (HCs) were recruited for the study. The monocyte subset counts in circulation were measured by flow cytometry, and serum interleukin- (IL-) 10 and IL-12 concentrations were tested by enzyme-linked immunosorbent assay. The potential association between clinical signs and monocyte subset counts was analyzed statistically. RESULTS: Compared with the HCs, the patients with early stage of IMN had higher counts of CD14(+)CD163(+), CD14(+)CD163(+)CD206(+), and CD14(+)CD163(+)CD206(+)CD115(+) M2-like monocytes. The CD14(+)CD163(+)CD206(+) M2-like cell counts and intracellular IL-10 concentrations in the monocytes were positively correlated with progression in proteinuria. The levels of serum IL-10 were significantly higher in early IMN patients than in the HCs. Furthermore, CD14(+)CD163(+)CD206(+) M2-like cell counts in the patients with incipient IMN were also positively related with 24 h urinary albumin levels and the values of serum M-type phospholipase A2 receptor (PLA2R). CONCLUSION: CD14(+)CD163(+)CD206(+) M2-like monocytes may contribute to the pathologic process in early-stage IMN and could serve as potential markers for evaluating the disease severity.