Assesment of risk factors for patients diagnosed with acute humoral rejection after kidney transplantation

Acute humoral rejection (AHR) has recently been recognized as an important cause of early renal allograft loss because it is frequently unresponsive to conventional antirejection therapy. After diagnosis, first year allograft survival is approximately 15-50%. Graft biopsy decision generally depends on the elevation of serum creatinine level; it leads late diagnosis and less treatment success. In this study we aimed to clarify the patients who have risk for AHR and improve their allograft survival by early diagnosis. 124 patients, who underwent kidney transplantation at Başkent University and diagnosed as AHR between 2006-2105, were included in the study. Another 75 patients without AHR diagnosis were added as control group. All subjects' data were investigated retrospectively according to AHR risk factors. Results revealed that donor age and previous blood transfusion were risk factors for AHR. The most important factor was presence of anti-HLA antibodies. There were 7 patients having positive anti-HLA antibody and all of them developed AHR during follow up period. After use of tacrolimus, AHR rate began to fall down. Higher AHR rate is seen in patients who were under mTOR inhibitor treatment. So tacromilus must be used in patients under AHR risk unless contraindication. Diffuse C4d staining and higher fibrosis index (>50%) in the pathology specimen, had worst graft survival compared to others. We determined higher serum creatinine level in patients with higher fibrosis index (2.2±0.9 mg/dL – 3.7±1.7 mg/dL). Their allograft loss was higher than low fibrosis index patients. In order to early diagnosis and better graft survival, PRA or if possible DSA must be performed periodically. Whenever this isn't possible protocol biopsy could be performed before early elevation of serum creatinine levels. Key words: Acute humoral rejection, Renal function, Graft survival