elevated levels of interleukin-21 in acute kidney injury after cardiopulmonary bypass surgery

Background: it is well-established that complications following cardiopulmonary bypass (cpb) such as acute kidney injury (aki) lead to worse outcomes and higher mortality. considering the importance of the post-cpb inflammatory cytokine cascade, we first assessed the post-operative interleukin (il)-21 serum level and its association with aki development after cpb.methods: in this experimental before-after study, 40 patients with confirmed cpb-aki in the jorjani heart center, bandar abbas (from january 2017 to september 2018) were compared with 50 non-aki patients. aki was defined according to the acute kidney injury network. the il-21 serum level was measured using an enzyme-linked immunosorbent assay before and 12 hours after surgery. the association between il-21 and other variables was evaluated by correlation analyses.results: the il-21 serum level was significantly higher post-operation compared to its level before surgery in aki (21.4 ± 6.3 and 15.7 ± 5.5, p < 0.001) and non-aki (19.1 ± 6.4 and 13.7 ± 6.3, p < 0.001) patients, but no significant differences were observed between aki and non-aki patients. age, body mass index, and creatinine were not significantly correlated with the il-21 serum level 12 hours post operations in aki and non-aki subjects.conclusion: serum il-21 concentrations were significantly increased in cpb patients after operation, which may contribute to the post-cpb inflammatory response syndrome. our data did not confirm any association between increased il-21 levels and cpb-aki risk.