Role of serum tumour necrosis factor alpha and its soluble receptors in predicting acute renal allograft rejection

Abstract

Tumour necosis factor alpha (TNF-o:) is known to be involved in pathogenesis of acute renal allograft rejection. However, measurement of cytokine serum levels alone are not a reliable index of acute rejection episodes. TNF-o: induces the release of soluble receptors (TNF-SR55 and TNF-SR75) that have an inhibitory activity and catabolized by the kidney. Twenty nine transplant recepients were studied and compared to ten healthy controls. TNF-o:, TNF-SR55 and TNF-SR75 were measured before and after renal transplantation. The mean pre-transplantation values were 26.3 ± 9.7 pg/ml, 28.2 ± 8.3 and 42.5 ± 11.1 ng/ml respectively. According to post-transplant course patients were divided into 3 groups. Group I (stable transplant group: no= 17): The mean level of TNF-o: value was 7.5 ± 4.6 pg/ml, TNF-SR55 6.4 ± 4.7 and TNF-SR75 12.5 ± 8 ng/ml (p NS). Group Il (acute allograft rejection group: no = 8): The mean values were 37.2 ± 16.2 pg/ml, 16.9 ± 9.6 and 30.9 ± 13.4 ng/ml respectively (p< 0.05). Group III cyclosporine (CS) nephrotoxicity group: no= 4): The mean level of TNF-o: was 9.9 ± 2.1 pg/ml with a highly significant increase in its receptor values (9.4 ± 1.0 & 21.2 ± 6.8 ng/ml; vs 5.5 ± 1.2 & 12.4 ± 4.8 ng/ml respectively (P< 0.0 I). To improve the predictive value of this cytokine and its receptors,we calculated the ratios of TNF-o: to both receptors (SR55-SR75). During acute rejection episode, the ratio values to control were 2.4 ± 0.6 vs 1.4 ± 0.7 and 1.3 ± 0.5 vs 0.7 ± 0.4 respectively (P<O.OI).