Quantitative assessment of serum Beta-2 Microglobulin in liver transplant recipients and relationship to liver graft rejection

OBJECTIVE: To investigate the usefulness of serum beta 2-microglobulin determination in the diagnosis of acute liver allograft rejection. DESIGN: Prospective study. SETTING: Liver transplant unit. PATIENTS: Twenty consecutive patients who underwent liver transplantation because of a non-virus-related end-stage liver disease. METHODS: Serum samples were collected before the transplant, at days 7, 30 and 90 and whenever a clinical complication developed after liver transplantation. beta 2-Microglobulin was quantified using a new quantitative automated microparticle enzyme immunoassay. RESULTS: Serum beta 2-microglobulin levels increased significantly (P < 0.05) during rejection episodes and correlated with the degree of hepatocyte injury as assessed using serum aspartate aminotransferase levels. Increased beta 2-microglobulin levels were also found in surgical or infectious post-transplant complications. A significant difference in beta 2-microglobulin values was recorded between patients with rejection and only those with bacterial sepsis. CONCLUSION: Although highly sensitive in recognizing damage to the graft, determination of beta 2-microglobulin was not sufficiently specific to differentiate between rejection and other post-transplantation complications.