De novo autoimmune hepatitis after living donor liver transplantation is unlikely to be related to immunoglobulin subtype 4-related immune disease

Background and Aim: Recently, we reported that immunoglobulin subtype 4 (IgG4) is involved in autoimmune hepatobiliary diseases, such as autoimmune hepatitis, sclerosing cholangitis, and pancreatitis. However, the association of IgG4 with autoimmune hepatic disease after living donor liver transplantation (LDLT) has not been investigated. Methods: Of the 72 LDLT recipients, four patients (5.6%) were suspected of having autoimmune-related hepatic disease after LDLT. The diagnosis was made based on a histological diagnosis following an examination of a biopsy liver specimen in three cases, while in one case a pemphigoid appeared in the flank with liver fibrosis of unknown cause. Human leukocyte antigen (HLA) mismatches were 3, 2, 2, and 2, respectively. The serum level of IgG4 in the patients was measured, and IgG4 immunohistochemical staining in the liver biopsy specimens was also performed. Results: In all cases, steroid pulse therapy or recycle treatment and subsequent increased steroid dose as well as additional azathioprine or mycophenolate mofetil were effective. While a few positive-stained cells for IgG4 were observed in the liver of one case, negative staining for IgG4 was observed in the other cases. All serum subclasses of IgG4 were within normal limits. Conclusion: In our series of LDLT, IgG4-related immune disorder is unlikely to be involved in post-transplant, autoimmune-related liver disease.