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.