Abstract
BACKGROUND Kidney transplantation is the most recommended treatment in chronic kidney disease. The recipient's immune system reacts to a kidney graft as to an alloantigen by producing antibodies (anti-human leukocyte antigens [HLAs]). Although immunosuppressive therapy is used to overcome this problem, the long-term survival of a kidney graft after 5 years remains low. This retrospective study from a single center in Romania of 347 renal transplant patients treated with tacrolimus, mycophenolate, and steroids aimed to evaluate the association between anti-HLA antibodies and 5-year graft survival. MATERIAL AND METHODS Anti-HLA antibodies were screened and identified using the Luminex method, while tacrolimus levels were monitored using the chemiluminescent assay. RESULTS Twenty-seven patients had pre-existing anti-HLA antibodies, while 320 patients did not. Of the 320 patients, 15% developed anti-HLA antibodies following kidney transplantation. The intrapatient minimum blood level of tacrolimus (cut-off value: 4.6 ng/mL) after transplantation was significantly associated with the risk of de novo anti-HLA antibodies (P<0.001). In patients with or without de novo anti-HLA antibodies, the 5-year allograft survival rate was 77.1% vs 90.8% (P=0.004). After Bonferroni correction, donor age (P=0.001), and donor type (P<0.0001) were statistically associated with the risk of allograft rejection. CONCLUSIONS This study showed that anti-HLA antibodies at 5 years after kidney transplantation were significantly associated with graft failure. The findings support previous studies and indicate that monitoring of anti-HLA antibodies should be considered in patients with renal transplant.