IL-17A Levels and Progression of Kidney Disease Following Hospitalization with and without Acute Kidney Injury.

Background: Acute kidney injury (AKI) is associated with increased mortality and new or progressive chronic kidney disease (CKD). Inflammatory cells play an important role in acute organ injury. We previously demonstrated that serum IL-17A levels were significantly elevated in critically ill patients with AKI and independently associated with hospital mortality. We hypothesize that IL-17A levels are elevated in hospitalized patients with AKI at diagnosis, and sustained elevation after discharge is associated with subsequent CKD incidence or progression.

Methods: Observational convenience sampling study of hospital survivors of Stage 2 or 3 AKI and controls without AKI from the ASSESS-AKI study. Patients were classified as progression or non-progression based on a composite of CKD incidence, progression, or end-stage kidney disease. IL-17A levels were evaluated with S-Plex assay (MSD) at 0- (during hospitalization), 3- and 12-month post-discharge, and analyzed along with clinical and biomarker data up to 84 months following discharge.

Results: Among 171 AKI and 175 non-AKI participants, IL-17A levels were elevated in AKI vs. non-AKI patients at 0M, 3M and 12M timepoints (p<0.05 for all comparisons). Further, IL-17A levels were elevated in the progression vs. non-progression group at the 3- and 12-month timepoints for outcomes occurring at 3-6 months and 12-84 months, respectively (p<0.05 for both). In adjusted multivariable models, IL-17A levels were not independently associated with progression of kidney disease. IL-17A levels were positively correlated with kidney disease and immune activation biomarkers at all timepoints (p<0.001).

Conclusions: IL-17A was higher in patients with AKI vs. without AKI during hospitalization and up to 1-year post-discharge. IL-17A was higher in patients with progression of kidney disease after hospitalization but not independently associated with subsequent progression of kidney disease in fully adjusted models.