Abstract
Immune dysregulation contributes to the pathogenesis of pediatric acute liver failure (PALF). Our aim was to identify immune activation markers (IAMs) in PALF that are associated with a distinct clinical phenotype and outcome. Among 47 PALF study participants, 12 IAMs collected ≤6 days after enrollment were measured by flow cytometry and IMMULITE assay on blood natural killer and cluster of differentiation 8-positive (CD8+ ) lymphocytes and subjected to unsupervised hierarchical analyses. A derivation cohort using 4 of 12 IAMs which were available in all participants (percent perforin-positive and percent granzyme-positive CD8 cells, absolute number of CD8 cells, soluble interleukin-2 receptor level) were sufficient to define high (n = 10), medium (n = 15), and low IAM (n = 22) cohorts. High IAM was more frequent among those with indeterminate etiology than those with defined diagnoses (80% versus 20%, P < 0.001). high iam was associated with higher peak serum total bilirubin levels than low iam (median peak 21.7 versus 4.8 mg dl, p >< 0.001) and peak coma grades. the 21-day outcomes differed between groups, with liver transplantation more frequent in high iam participants (62.5%) than those with medium (28.2%) or low iam (4.8%) (p =" 0.002);" no deaths were reported. in an independent validation cohort (n =" 71)" enrolled in a prior study, segregation of iam groups by etiology, initial biochemistries, and short-term outcomes was similar, although not statistically significant. high serum aminotransferases, total bilirubin levels, and leukopenia at study entry predicted a high immune activation profile. four circulating t-lymphocyte activation markers identify a subgroup of palf participants with evidence of immune activation associated with a distinct clinical phenotype and liver transplantation; these biomarkers may identify palf participants eligible for future clinical trials of early targeted immunosuppression.> 0.001)> 0.001).>