Background : Acute liver graft rejection is still a common complication after liver transplantation. Diagnosis of acute cellular rejection (ACR) requires a liver biopsy with attendant expense, and risk, especially for developing country. Measurements of serum complement components C3 and C4 are useful in the diagnosis and monitoring of immune complex disease. The normal adult range of C4 is 20-50mg/dl. Low levels of C4 strongly suggest immune complex disease. The combination C4 and ALT levels are highly predictive of acute cellular rejection (ACR) in liver transplant recipients. A lowered concentration or the complete absence of C4 occurs in immunocomplex diseases, systemic lupus erythematosus (SLE), autoimmune thyroiditis and juvenile dermatomyositis.

Methods : This study has two groups, one group comprised 8 liver transplant recipients, who has predictive diagnosis of ACR. The other group comprised 8 liver transplant recipients, who has not prediction of ACR. Pathologist evaluated the ACR by Banff grading schema. Serum C4 was checked Cobas 6000/c501/ analyzer.

Results : ACR patients had an average of C4 ≤ 0.22 gm/L test, ALT ≥ 124 IU/ml. The patients without ACR had an average of C4 ≥0.61 gm/L test, ALT ≤ 87 IU/ml. The ACR patients had done needle biopsy, which showed liver rejection.

Conclusions : To detect serum C4 in blood is a relatively non-invasive, inexpensive, easy to measure and quick marker. Especially for developing country like Mongolia, preliminary diagnosis of ACR, which revealed decreasing C4 and increasing ALT convenient to biopsy results.