Clinical correlation of nitric oxide levels with acute rejection in renal transplantation

The objective of this study was to examine whether there was an association between acute rejection (AR) and nitric oxide (NO) levels and also to evaluate the clinical impact of NO measurement as a noninvasive marker for early detection of AR. Fifty consecutive patients aged 17-62 years old received a living-related kidney graft. Serum levels of total nitrite and nitrate (NOx) were measured 30 min after graft reperfusion (NOx 1) and on days 1 (NOx 2), 5 (NOx 3), and 10 (NOx 4) post-transplantation (Tx). If clinically indicated, graft biopsy was performed. Acute humoral rejection was diagnosed by biopsy on 3rd post-Tx day in one patient. His serum NOx 2 levels were remarkably higher (380%) compared with his NOx 1 measurement. At the same time, NOx 1-2 measurements in uncomplicated group showed lower levels (-12%). Additionally, during the first month post-Tx, 5 cases of acute cellular rejection (ACR) were diagnosed. The mean percent change of NOx 3-4 levels in ACR group was 180.7 versus 16.1 in uncomplicated patients (P < 0.01). In addition, > 70 mu mol/L change in NOx levels in consecutive samples had a sensitivity of 100% and a specificity of 97.7% in predicting AR episodes. Our study reports significant increase in serum NOx levels in episodes of AR. NOx might be an useful noninvasive marker for early diagnosis of AR.