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.