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

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.