https://pubmed.ncbi.nlm.nih.gov/34454951/ NAFLD

J Pediatr. 2021 Aug 26;S0022-3476(21)00826-X.
doi: 10.1016/j.jpeds.2021.08.041.Online ahead of print.

Prevalence and Clinical Significance of Autoantibodies in Children with Overweight and Obesity with Non-Alcoholic Fatty Liver Disease

Ammar Khayat 1, Bernadette Vitola 2

Abstract

Objectives: To evaluate the prevalence and clinical significance of autoantibodies in children with overweight and obesity with non-alcoholic fatty liver (NAFL), and non-alcoholic steatohepatitis (NASH) in comparison with those with autoimmune liver disease (ALD).

Study design: This is a retrospective, cross-sectional study in 2007-2016, of children with a biopsy proven diagnosis of NAFL, NASH, autoimmune hepatitis (AIH), or primary sclerosing cholangitis (PSC), and a body mass index (BMI) >85th percentile.

Results: A total of 181 cases were identified; 31 (17%) had NAFL, 121 (67%) had NASH; 12 (6.6%) had ALD (AIH, PSC, or overlap), and 17 (9.4%) had combined ALD and NAFLD. Antinuclear antibody (ANA), Anti-actin, and liver kidney-microsomal (LKM) antibodies were positive in 16.1%, 13.8%, and 0% of NAFL and 32.8%, 15.5%, and 0% of NASH cases, respectively. Total IgG was elevated in 27.3% of NAFL and 47.7% of NASH cases but in 100% of ALD cases. The positive predictive value of LKM for ALD was 100% but was only 29% for ANA and 46% for anti-actin antibody.

Conclusions: False positive rates of autoantibodies were higher in pediatric patients with overweight and obesity with NAFLD compared with the adult general population. Positive LKM had the highest specificity and positive predictive value, and elevated IgG level had the highest sensitivity for ALD. The presence of autoantibodies does not signal more severe NAFLD in children. BMI > 98th percentile seems to be an important breakpoint above which ALD is less likely.