Clinical and histopathological features of immunoglobulin G4-associated autoimmune hepatitis in children.

ABSTRACT

BACKGROUND AND AIM: We aimed to examine the frequency and the characteristics of immunoglobulin G4 (IgG4)-associated autoimmune hepatitis among pediatric patients with autoimmune hepatitis. METHODS: Immunostaining for IgG and IgG4 was performed in liver biopsies of 40 pediatric patients with autoimmune hepatitis. The patients with more than 10 IgG4-positive plasma cells/high-power field were defined as IgG4-associated autoimmune hepatitis. Clinic, laboratory, and histopathological results were compared between groups. RESULTS: Among the 40 pediatric patients, 34 patients were type 1 and 6 patients were type 2 autoimmune hepatitis. Six patients (15%), four of the type 1 and two of the type 2 autoimmune hepatitis patients, were diagnosed with IgG4-associated autoimmune hepatitis. Clinical, laboratory, and histopathological data were initially similar in both forms. There was a positive correlation between IgG4-positive plasma cell count and degree of portal (r 0.406, P 0.009) and lobular inflammation (r 0.37, P 0.019), grade of interface hepatitis (r 0.33, P 0.03), and fibrosis (r 0.318, P 0.046). Time required for normalization of liver transaminases and serum IgG level was significantly shorter in IgG4-associated autoimmune hepatitis (3.3 ± 0.5 vs 6.6 ± 3.5 for alanine aminotransferase, 3.7 ± 0.8 vs 6.7 ± 1.2 for aspartate aminotransferase, 4.3 ± 1.2 vs 7.1 ± 2.7 for gamma-glutamyl transpeptidase, and 7.2 ± 3.1 vs 12.8 ± 4.5 for IgG). CONCLUSIONS: Immunoglobulin G4-associated autoimmune hepatitis can be found in pediatric age group and also in type 2 autoimmune hepatitis patients. As steroid response may be better in IgG4-associated autoimmune hepatitis, biopsy specimens should be evaluated for this entity at diagnosis.