Marginating-hepatic (MH) leukocytes (leukocytes adhering to the sinusoids of the liver), were shown to exhibit unique composition and characteristics compared to leukocytes of other immune compartments. Specifically, evidence suggests a distinct pro- and anti-inflammatory profile of the MH-leukocyte population and higher cytotoxicity of liver-specific NK cells (namely, pit cells) compared to circulating or splenic immunocytes in both mice and rats. The method presented herein enables selective harvesting of MH leukocytes by forced perfusion of the liver in mice and rats. In contrast to other methods used to extract liver-leukocytes, including tissue grinding and biological degradation, this method exclusively yields leukocytes from the liver sinusoids, uncontaminated by cells from other liver compartments. In addition, the perfusion technique better preserves the integrity and the physiological milieu of MH leukocytes, sparing known physiological responses to tissue processing. As many circulating malignant cells and infected cells are detained while passing through the liver sinusoids, physically interacting with endothelial cells and resident leukocytes, the unique MH leukocyte population is strategically located to interact, identify, and react towards aberrant circulating cells. Thus, selective harvesting of MH-leukocytes and their study under various conditions may advance our understanding of the biological and clinical significance of MH leukocytes, specifically with respect to circulating aberrant cells and liver-related diseases and cancer metastases.