Levels of tumor necrosis factor (TNF) in sera of renal allograft recipients

A biological assay was used for monitoring serum levels of endogenous tumor necrosis factor in 42 renal transplant recipients. The clinical events occurring in the post-transplant period were categorized as follows: group I, acute rejection (12); group II, acute tubular necrosis (ATN, 16); group III, cyclosporine A (CyA) nephrotoxicity (13); group IV, uncomplicated transplants (22); group V, viral (6)/bacterial (4) infections. Twenty-one health subjects served as controls (group VI). Serum TNF levels were measured every other day after transplantation for 44.2 +/- 4.18 d (mean +/- SEM). The means of serum TNF levels of each week for 3 wk after the beginning of each clinical event were calculated and statistical evaluation was performed between groups. In the 1st, 2nd but not in the 3rd wk of observation, acute rejection was associated with significantly increased serum TNF levels in respect to ATN, CyA nephrotoxicity, uncomplicated transplants and healthy subjects. In the 1st but not in the 2nd wk, acute rejection did not differ from viral/bacterial infections. ATN was associated with significantly increased serum TNF levels vs. uncomplicated transplants at the end of the 1st but not of the 2nd or 3rd wk. CyA nephrotoxicity showed no significant increase in serum TNF levels vs. uncomplicated transplants in all 3 wk of observation. Early monitoring of the concentrations of TNF in serum therefore may provide an additional parameter for the differential diagnosis of acute rejection in respect to CyA nephrotoxicity, provided that intercurrent infections can be excluded.