Prevalence and Significance of Autoantibodies in Children With Acute Liver Failure

ABSTRACT Objectives: The purpose of the present study is to estimate autoantibody (auto‐AB) frequency, clinical characteristics, and 21‐day outcome of participants in the Pediatric Acute Liver Failure Study Group (PALFSG) by antinuclear antibody, smooth muscle antibody, and liver‐kidney microsomal (LKM) antibody status. Methods: Auto‐ABs were determined at local and/or central laboratories. Subjects were assigned to autoimmune hepatitis (AIH), indeterminate, and other diagnoses groups. Results: Between 1999 and 2010, 986 subjects were enrolled in the PALFSG. At least 1 auto‐AB result was available for 722 (73.2%). At least 1 auto‐AB was positive for 202 (28.0%). Diagnoses for auto‐AB+ subjects were AIH (63), indeterminate (75), and other (64). Auto‐ABs were more common in Wilson disease (12/32, 37.5%) compared with other known diagnoses (52/253, 20.6%, P = 0.03). LKM+ subjects were younger (median 2.4 vs 9.1 years, P < 0.001) and more likely to undergo liver transplantation (53.3% vs 31.4% P = 0.02) than other auto‐AB+/LKM− subjects. Steroid treatment of subjects who were auto‐AB+ was not significantly associated with survival and the subgroup with known diagnoses other than AIH had a higher risk of death. Conclusions: Auto‐ABs are common in children with acute liver failure, occurring in 28%. Auto‐AB+ subjects have similar outcomes to auto‐AB negative subjects. LKM+ children are younger and more likely to undergo liver transplantation compared with other auto‐AB+ subjects. Although auto‐AB may indicate a treatable condition, positivity does not eliminate the need for a complete diagnostic evaluation because auto‐ABs are present in other conditions. The significance of auto‐AB in pediatric acute liver failure remains uncertain, but LKM+ appears to identify a unique population of children who merit further study.