One of the main functions of the lymphatic system is to filter blood. How exactly is it done? Its quite hard to find an exact answer.
The spleen is an integral part of the lymphatic system, and it is a major filter of blood.
The way this is done is by removing old, distorted, or antibody-coated red blood cells from circulation.
Interestingly, the spleen is enlarged with many leukemias and lymphomas.