Children with chronic renal failure have reduced numbers of memory B cells

SUMMARY Reduced serum IgG and subclass levels have been demonstrated in children with chronic renal failure. To study possible causes of this reduction, we analysed B cell subset composition, T helper cell frequencies and immunoglobulin (Ig) production capacity in vitro in children with chronic renal failure, with or without dialysis treatment. B cell subsets were characterized by determining CD27, IgM, IgD and CD5 expression within the CD19 + population. Intracellular expression of interferon (IFN)‐ γ , interleukin (IL)‐2 and IL‐4 in PMA/ionomycin‐stimulated peripheral blood mononuclear cells (PBMC) was used to evaluate T helper frequencies. The capacity of B cells to secrete Ig in vitro was determined by measuring IgG 1 , IgG 2 and IgM in culture supernatants of anti‐CD2/CD28 monoclonal antibody (MoAb)‐ or SAC/IL‐2‐stimulated PBMC. Memory B cell numbers (identified as percentage or absolute number of CD19 + IgM¯IgD¯ or CD19 + CD27 + lymphocytes) were lower in children treated with haemodialysis (HD), peritoneal dialysis (PD) and children with chronic renal failure before starting dialysis treatment (CRF) compared to healthy controls (HC) ( P  < 0·05). Compared with HC, CD5 + (naive) B cells were reduced in HD‐treated patients but not for PD or for children with chronic renal failure before starting dialysis treatment (CRF). No significant differences in CD4 + T helper cell subsets were found between the groups. However, CRF children had a higher percentage of IFN‐ γ producing CD8 + T lymphocytes compared to HC ( P  = 0·02). Finally, IgG 1 , IgG 2 and IgM production in vitro was similar in the four groups. In conclusion, significantly lower numbers of memory type B cells were found in children with chronic renal failure compared to healthy controls. This reduction may contribute to the low Ig levels found in these children.