Activation of basophils is a new and sensitive marker of biocompatibility in hemodialysis.

The hemodialysis procedure involves contact between peripheral blood and the surface of dialyzer membranes, which may lead to alterations in the pathways of innate and adaptive immunity. We aimed to study the effect of blood-membrane interaction on human peripheral basophils and neutrophils in hemodialysis with high- and low-permeability polysulfone dialyzers. The surface expression of CD203c (basophil selection marker) and CD63 (activation marker) after activation by the bacterial peptide formyl-methionyl-leucyl-phenylalanine (fMLP) or anti-Fcε receptor I (FcεRI) antibody and the absolute number of basophils was investigated before and after hemodialysis with each of the dialyzers. Moreover, the expression on neutrophils of CD11b, the CD11b active epitope, and CD88 was analyzed in the same groups of individuals. The expression of CD63 in basophils following activation by fMLP was significantly higher in the patient group compared with that in healthy controls, but no differences were observed after activation by anti-FcεRI. During the hemodialysis procedure, the low-flux membrane induced up-regulation of CD63 expression on basophils, while passage through the high-flux membrane did not significantly alter the responsiveness. In addition, the absolute number of basophils was unchanged after hemodialysis with either of the dialyzers and compared with healthy controls. We found no significant differences in the expression of the neutrophil activation markers (CD11b, the active epitope of CD11b, and CD88) comparing the two different dialyzers before and after dialysis and healthy controls. Together, these findings suggest that alterations in basophil activity may be a useful marker of membrane bioincompatibility in hemodialysis.

Leukocyte proliferation and immune modulator production in patients with chronic kidney disease.

INTRODUCTION: In Chronic Kidney Disease (CKD), immune cells are affected by uremic retention toxins. Given this effect, we analyzed lymphocyte proliferative response and immune modulators production following in vitro stimulation. METHODS: Whole blood was drawn from healthy controls, patients with eGFR <20 ml/min/1.73 m(2) (Pre-dialysis, CKD stages 4 and 5) and hemodialysis patients (stage 5D). Peripheral cells were incubated for six days with pokeweed mitogen, concanavalin A, Staphylococcus enterotoxin A or influenza A vaccine. Peripheral lymphocyte proliferation was then analyzed by the "Flow-cytometric Assay of Specific Cell-mediated Immune response in Activated whole blood" (FASCIA) method, and cytokine profile in the cell supernatants was analyzed by the Milliplex multi-array method. RESULTS: The absolute number of lymphoblasts in response to mitogenic stimulation and the number of cells in each CD4+ and CD8+ subpopulation were similar comparing the three groups, except for a single decline in number of lymphoblasts after stimulation with Staphylococcus enterotoxin A, comparing dialysis patients with healthy controls. Levels of interleukin (IL)-2 (p=0.026), -10 (p=0.019) and -15 (p=0.027) in the Staphylococcus enterotoxin A-stimulated supernatant were lower in hemodialysis patients compared to healthy controls. Levels of IL-15 (p=0.017) from pre-dialysis patients and levels of IL-5 (p=0.019) from hemodialysis patients in influenza A vaccine-stimulated supernatants were also lower compared to controls. In pokeweed mitogen-stimulated supernatant, IL-2 levels (p=0.013) were lower in hemodialysis patients compared to pre-dialysis patients. TNF-α, IL-10, IL-12, IL-15, IL-8, MCP-1, IP-10, IFN-α2, IL-1α and eotaxin levels were all significantly higher in plasma obtained from CKD patients. CONCLUSION: Our results suggest that T-cells from CKD patients have similar proliferative response to stimulation compared with healthy individuals. Moreover, however the immune cells show inability to produce selected cytokines, most likely due to the uremic milieu or dialysis procedure.

Expression of neutrophil SOD2 is reduced after lipopolysaccharide stimulation: a potential cause of neutrophil dysfunction in chronic kidney disease.

BACKGROUND: Neutrophils from patients with chronic kidney disease (CKD) are dysfunctional and thus a contributing factor to the risk of infections. The mechanisms for leucocyte dysfunction in CKD are not fully understood. It is known that lipopolysaccharide (LPS) activates transcription of several genes encoding proinflammatory cytokines. We therefore aimed to study the effect of LPS on neutrophil expression of genes related to the inflammatory response to address the hypothesis that LPS-induced gene transcriptions are altered in CKD patients. METHODS: We analysed gene expression of LPS-stimulated neutrophils from 30 patients with CKD and 15 healthy controls. Superoxide dismutase-2 (SOD2), IL1A, IL-1R1, IL-1R2 and IL8RA gene expression from both neutrophils and differentiated HL60 cells were measured by quantitative polymerase chain reaction. Differentiated HL60 cells were stimulated with phorbol-12-myristate-7-acetate (PMA) after inhibition of SOD2 by small interfering RNA followed by respiratory burst assessment using flow cytometry. RESULTS: LPS stimulation induced a significant mobilization of CD11b on neutrophils from CKD and healthy controls. Upregulation of SOD2, IL1A, IL-1R1 and IL-1R2 gene expression in neutrophils from healthy controls after LPS stimulation was contrasted by no change in gene transcription (IL-1R1 and IL-1R2) or even a downregulation in patients with CKD (SOD2 and IL1A). Inhibition of SOD2 reduced the PMA-induced respiratory burst and IL1A, IL-1R1, IL-1R2 and IL8RA gene expression in neutrophil-differentiated HL60 cells. CONCLUSIONS: Because of the critical role of SOD2 in the generation of hydrogen peroxide during phagocytosis, downregulation of SOD2 gene expression after LPS stimulation in neutrophils from patients with CKD indicates a potential mechanism for neutrophil dysfunction and cytokine dysregulation in these patients.

Neutrophil activation during transmigration in vivo and in vitro A translational study using the skin chamber model.

Neutrophil transmigration can be studied in vitro by use of the transwell model and in vivo by the skin chamber model. Activation during transmigration involves translocation of secretory vesicles and granules to the plasma- and phagolysosome membranes. In this study, we compared the skin chamber model with the transwell model, focusing on the mobilization of CR1 (CD35), CR3 (CD11b/CD18) and CD63 from intracellular vesicles and granules. In addition, functional responses towards a bacterial related stimulus, formyl-methionyl-leucyl-phenylalanine (fMLP), in terms of CR3 expression and production of reactive oxygen species (ROS) were assessed. Discrepancies between the skin chamber model and the transwell model were observed. The expression of CR1 increased following in vivo transmigration (p<0.001) and, in contrast, decreased following in vitro transmigration (p=0.004). Furthermore, CR1 was mobilized following an isolation procedure included in the transwell model. The expression of CR3 increased following both in vivo (p<0.001) and in vitro (p=0.03) transmigration. However, in vitro transmigration did not influence the fMLP induced CR3 expression which was significantly increased following in vivo transmigration (p=0.01). In addition, the fMLP induced production of ROS was significantly reduced following in vitro transmigration (p=0.002) but unaltered after in vivo transmigration, indicating differences between the impact of the two systems on cellular activation. The observed discrepancies between the two models might be partly explained by granule mobilization and neutrophil priming, induced during the isolation procedure included in the transwell model, which results in an altered cellular activation. Therefore, mobilization of granules needs to be accounted for when interpreting data from different model systems.