Background: Pediatric Acute Liver Failure (PALF) is a rare condition with significant morbidity and mortality. In many affected children, a specific etiology is never identified. These patients are labeled indeterminant (IND-PALF) and often have worse outcomes compared to children with a known cause. In 2021and early 2022, clusters of children with acute hepatitis/PALF were identified in children globally. Adenovirus type 41, a common cause of acute gastroenteritis, was detected in blood of many cases prompting proposal of broader testing strategies including testing for adenovirus. Adenovirus has historically been an uncommon etiology of PALF in immunocompetent children, and whether it was causative remains unclear. There is a paucity of large-scale data regarding the potential contribution of adenovirus to the development of PALF.

Methods: The Pediatric Acute Liver Failure Study Group (PALFSG, U01 DK072146) was an NIH-funded prospective observational study that enrolled PALF patients between 1999-2014 and collected clinical data and biospecimens. We tested 85 serum and 46 plasma IND-PALF PALFSG subject samples for pan-adenovirus by real time PCR. IND-PALF cases were compared to controls (final diagnosis other than IND-PALF) and were matched for age and month-year of admission.

Results: Adenovirus was detected in 7/262 (3%) samples - 4 IND-PALF samples (3/85 [4%] plasma, 1/46 [2%] serum) and 3/85 (4%) serum from patients with other diagnosis (Valproate drug-induced liver injury [DILI, Acetaminophen DILI, and Wilson’s Disease). Two IND-PALF subjects with a positive adenovirus test on this analysis had previous negative adenovirus PCR results recorded in the PALFSG database. The other 5 subjects did not have any prior adenovirus testing recorded. PCR Cycle threshold (Ct) values ranged from 25.68-38.86, with a median of 35.23 (interquartile range 30.11-37.66). Ct values for 3 subjects were ≥ 37 which is close to the detection limit of 40, indicating they contained very few adenovirus genomes. The 2 subjects with the lowest Ct values (highest viral load) had alternative diagnoses.

Conclusion: Interrogating PALFSG biorepository samples for adenovirus prevalence in IND-PALF yielded few positive cases with relatively low viral RNA levels. The number of positive cases and controls were similar. While further comprehensive viral testing may be needed, these data suggests that adenovirus is unlikely to be a cause of IND-PALF in this historical cohort.