KTeXpand - a novel microfluidic device for advanced cell based cross matching

Antibody-mediated rejection after kidney transplantation is a major limitation for long-term survival of donated kidneys within the recipient allograft. With the existing HLA cross-matching test only complement activating donor specific antibodies are evaluated. Other measurements are more sensitive, but cannot assert the clinical relevance of the donor specific antibodies. Thus, novel methods that address the more complex nature of cellular interactions with serum components are needed to improve antibody-mediated rejection prediction. Recent studies suggest, that the interaction of natural killer cells of the recipient with endothelial cells of the donor is of major interest. Here we present a microfluidic cell culture device and a corresponding assay to test for the relevance of natural killer cell activated antibody-mediated rejection in vitro. Therefore, a protocol to co-cultivate both cell types and track natural killer cell activated killing within a fluorescence-based assay was established. To automate this approach, the prototype of a well plate sized microfluidic device was developed, that enables staining of the two cell types and repeatable and time-dependent co-cultivation of the cells with serum. This automated approach enables further evaluation of the clinical relevance of the established assay paving the way to additional information on HLA cross-matching that helps to quickly estimate the probability of Antibody-mediated rejection and the clinical relevance of donor specific antibodies.