Figure 7
Schematic representation of BAK. The BAK device is composed of multiple HFM containing tight monolayers of ciPTEC for efficient removal of protein-bound uremic toxins. Uremic toxins bound to albumin can be taken up by ciPTEC from the blood side, and secreted into the dialysate compartment of the BAK. The presence of the polymer membrane should be sufficient to block direct interaction of host blood cells, in particular T cells, and ciPTEC via T-cell receptors and HLA molecules, thereby preventing direct activation of an immune response. However, there is a possibility of an immune response towards microvesicles, soluble allo-antigens or other cellular components that might be released by ciPTEC. In that case, it can be expected that host APC could present ciPTEC-specific antigens to helper T cells, thus leading to a semi-direct or indirect pathway of immune response activation21. Once activated, helper T cells can cause the activation of other cells such as cytotoxic T cells, as well as B cells and macrophages by releasing pro-inflammatory cytokines. This could potentially also lead to a non-specific inflammatory response, especially due to the excessive secretion of pro-inflammatory mediators by activated immune and inflammatory host cells.
