The Role of IL-10-Producing Regulatory B Cells in Children With Primary Nephrotic Syndrome

This study aimed to investigate the contribution of interleukin (IL)-10-producing regulatory B cells (B10 cells) to the pathogenesis of PNS.

The percentages of B10 cells, CD19⁺CD24^hiCD27⁺ B cells, CD19⁺CD24^hiCD38^hi B cells, CD19⁺CD24^hiCD27⁺IL-10⁺ B cells, CD19⁺CD24^hiCD38^hiIL-10⁺ B cells, Th17 cells, and regulatory T (Treg) cells within the peripheral blood mononuclear cells (PBMCs) from healthy subjects and PNS patients with active disease or in remission were analysed by flow cytometry.

The percentages and IL-10 production of circulating B10 cells and the two subsets were decreased in children with active PNS and returned to normal levels in PNS patients in remission. B10 cells and their subsets were negatively correlated with the Th17/Treg ratio. The percentages of B10pro+B10 cells, CD19⁺CD24^hiCD27⁺IL-10⁺ B cells, CD19⁺CD24^hiCD38^hiIL-10⁺ B cells, Th17 cells, Treg cells, and the Th17/Treg ratio did not significantly differ between groups after CpG and CD40L stimulation. However, in the presence of CpG and anti-CD40L mAb, the percentages of B10pro+B10 cells, CD19⁺CD24^hiCD27⁺IL-10⁺ B cells, CD19⁺CD24^hiCD38^hiIL-10⁺ B cells, and Treg cells were significantly reduced, whereas the Th17 cell percentage and the Th17/Treg ratio were significantly increased. Furthermore, the Th17/Treg ratio correlated negatively, whereas the percentages of B10 cells and their subsets correlated positively with serum immunoglobulin G (IgG) concentration.

Our study demonstrates that the numbers of B10 cells and their ability to produce IL-10 are decreased, leading to an imbalance in the Th17/Treg ratio and low IgG levels, which may then contribute to the pathogenesis of PNS.