Hepatic draining lymph nodes in human liver transplant: Implications in alloimmunity and tolerance

Background: Hepatic draining lymph nodes (HDLN) are implicated in allograft alloimmunity and tolerance. In contrast to experimental work, the role of HDLNs in human liver transplant (LT) is unknown due to lack of relevant clinical tissue.

Methods: During LT, the porta hepatis was dissected near the liver hilum during native hepatectomy. The HDLN in this region was taken prior to reperfusion (prereperfusion). Following complete reperfusion with recipient portal venous blood, hepatic arterial inflow into the allograft was established. As the recipient's common hepatic artery was fully mobilized, its HDLNs were removed and submitted to pathology (postreperfusion).

Results: Of 37 LTs performed between January 1, 2021, and July 9, 2022, 20 had both pre- and postreperfusion HDLNs archived (Group A); 11 had only postreperfusion HDLNs archived (Group B), and 6 had no archived HDLNs (Group C). Removing and archiving HDLNs did not increase operative times or transfusion requirements. For groups A, B, and C, mean (SD) warm ischemic times were 25.2 (2.0), 25.3 (3.2), and 28.3 (6.2) minutes, respectively (P > .05); operating times were 3.9 (0.7), 6.9 (7.8), and 7.9 (7.1) hours, respectively (A vs C, P = .017; C vs B, P > .05); and units of transfused packed red blood cells were 8.0 (3.8), 11.1 (10.3), and 12.2 (7.6), respectively (P > .05).

Conclusion: We describe an approach for clinical archiving of HDLNs obtained within the operative field during orthotopic LT in humans. Availability of relevant HDLNs is essential for investigations of primary immune responses potentially important in allograft alloimmunity and tolerance.