B-cell differentiation and T-cell cytokine production in children with chronic renal failure

Introduction: It has been reported that the antibody response to immunizations is reduced in uremic patients. Creating "immunological memory" is important for a strong antibacterial and antiviral defence. It is not known whether B-cell maturation is disturbed in these children. Furthermore, B-cell activation is regulated by T-cell cytokines. The aim of the present study was to analyse B-cell differentiation and T-cell cytokine production in children with chronic renal failure, with or without dialysis treatment. Patients/Methods: Eight children treated with peritoneal dialysis (PD), 8 on hemodialysis (HD), 9 children not yet dialyzed (CRF) and 9 healthy children (HC) were studied. Peripheral blood mononuclear cells (PBMC) were isolated from heparin blood by Ficoll-isopaque density centrifugation. For B-cell analysis PBMC were incubated with saturating amounts of CD19, CD27, IgM, IgD, and CD5 monoclonal antibodies (moAb). Subsequently, cells were analyzed by flow cytometry. For T-cell analysis PBMC were stimulated with mitogen (PMA/Ionomycin) for 4 hr. Cells were then stained for intracellular cytokines, IFN-γ IL-2 and IL-4, and analyzed by flow cytometry. Results: The median (range) absolute count of total lymphocyte number and B cell subpopulations are shown in Table 1. Tabel 20 Phenotypic characteristics of CD19⁺ B-lymphocytes. PD HD CRF HC Lymphocytes 2.8 (2.2-3.2) 1.9 (0.6-3.5)* 2.0 (0.9-3.0)** 2.8 (2.1-4.2) CD19⁺ 0.68 (0.13-0.97) 0.22 (0.07-1.33)* 0.73 (0.07-2.09) 0.56 (0.35-0.96) IgM^-IgD^- 0.08 (0.04-0.11) 0.05 (0.004-0.15)* 0.04 (0.004-0.25) 0.09 (0.06-0.14) CD27⁺ 0.07 (0.03-0.13)* 0.04 (0.01-0.15) * 0.09 (0.02-0.29) 0.13 (0.06-0.28) CD5⁺ 0.21 (0.02-0.52) 0.03 (0.01-0.16)** 0.11 (0.02-0.88) 0.18 (0.06-0.45) Absolute numbers (x 10⁹/L) * p < 0.05, ** p < 0.01, when compared with HC (nonparametric unpaired t-test). PD children had a lower CD27⁺ B-cell count compared to HC. HD patients showed reduced numbers of total lymphocyte count and all B-cell subsets when compared to HC. CRF children had a reduced lymphocyte count compared to HC and the IgM/IgD double negative B-cell number tended to be lower. CD5⁺ B-cells were lower in HD children compared to HC. CRF children had a higher percentage IFN-γ producing CD8⁺ (T-suppressor) lymphocytes (median 42%, range 23-75) compared to HC (22%, 14-72, p=0.02) and HD (27%, 16-50, p = 0.03). The IL-2 producing CD4⁺ (T-helper) cell population was also higher in CRF children (31%, 15-38) in comparison with HD (19%, 7-24, p=0.03) but similar to HC (24%, 12-42). No significant differences were found for IL-4. Conclusion: The lower CD27⁺ and IgM^-/IgD^- B-cell count in uremic children implicates that they are less capable to mount an immunological memory as do healthy children. Significant differences were especially found in HD patients. T-cell cytokine production is higher in children with CRF, before starting dialysis treatment. It is not clear whether the dialysis treatment restores the cytokine profiles.