Abstract: Biological filters for removing target components from biological fluids such as removal of pathogenic cells from whole blood, are described. The filters may include a medium comprising an inert surface, with capture material disposed on the inert surface. The filter may be configured to selectively recognize, capture, and remove target cells such as pathogenic cells associated with a disease, such as an autoimmune disease or cancer. Devices, systems, apparatuses, computer readable media, and methods associated with biological filtering are also provided.