Immunoglobulin G4 (IgG4)-related autoimmune hepatitis and IgG4-hepatopathy: A histopathological and clinical perspective

A case of atypical IgG4-related disease presenting hypereosinophilia, polyneuropathy, and liver dysfunction

Ig (immunoglobulin) G4-related disease (Ig4-RD) affects several organs, including salivary glands, lacrimal glands, pancreas, biliary ducts, and retroperitoneum. A 72-year-old woman was examined for hypereosinophilia, high levels of IgG4, polyneuropathy, liver dysfunction, enlargement of lymph nodes and lacrimal glands, and beaded dilation of the bile ducts. We diagnosed Ig4-RD based on biopsies of the lymph nodes, liver, and submandibular gland. The symptoms of the patient improved after glucocorticoid treatment. This was a novel and atypical case of Ig4-RD that was difficult to differentiate from other diseases, including eosinophilic granulomatosis with polyangiitis, idiopathic hypereosinophilic syndrome, and polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, skin changes syndrome. This case report highlights the importance of biopsies in differentiating Ig4-RD.

Immunoglobulin G4-related Tubulointerstitial Nephritis with Simultaneous Resolution of Plasma Cell Infiltration and Fibrosis after Steroid Treatment

We performed 3 kidney biopsies in a 71-year-old man. At the first biopsy, we made the diagnosis of immunoglobulin G4 (IgG4)-related interstitial nephritis characterized by the simultaneous presence of IgG4-positive plasma cells and characteristic fibrosis with a bird's-eye pattern. At the second biopsy, rather than finding fibrosis as a post-inflammatory scar, we noted that steroid treatment had caused the simultaneous disappearance of IgG4-positive plasma cells and fibrosis and had restored the normal tubular structure. The third biopsy showed the recurrence of the disease with inflammatory cells accompanied by fibrosis. These findings suggest that IgG4-positive plasma cells and fibrosis occur simultaneously.

Immunoglobulin G4-related Hepatopathy after COVID-19 Vaccination

An 84-year-old woman with immunoglobulin G4 (IgG4)-related disease presented with jaundice and liver dysfunction after COVID-19 vaccination. Serum IgG4 levels were elevated. Diagnostic imaging showed no stenotic lesions in the bile ducts. A liver biopsy was performed because of the enlarged liver. Infiltration of IgG4-positive plasma cells, which accounted for approximately 74% of total plasma cells, was found in the portal area, but there was no evidence of periportal hepatitis, and inflammatory cell infiltration into the lobular space was minimal. IgG4-related hepatopathy was diagnosed. The patient achieved spontaneous remission with no treatment and only follow-up and remains under observation at the time of writing.

Autoimmune liver diseases in systemic rheumatic diseases

Systemic rheumatic diseases (SRDs) are chronic, inflammatory, autoimmune disorders with the presence of autoantibodies that may affect any organ or system. Liver dysfunction in SRDs can be associated with prescribed drugs, viral hepatitis, alternative hepatic comorbidities and coexisting autoimmune liver diseases (AILDs), requiring an exclusion of secondary conditions before considering liver involvement. The patterns of overlap diseases depend predominantly on genetic determinants with common susceptible loci widely distributing in both disorders. In AILDs, it is important to identify the overlapping SRDs at an early stage since such a coexistence may influence the disease course and prognosis. Commonly co-occurring SRDs in AILDs are Sjögren syndrome (SS), rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) in autoimmune hepatitis (AIH), and SS, RA or systemic sclerosis in primary biliary cholangitis. Owing to different disease complications and therapies, it is imperative to differentiate between SLE liver involvement and SLE-AIH overlap disease. Therapeutic options can be personalized to control coexisting conditions of liver autoimmunity and rheumatic manifestations in AILD-SRD overlap diseases. The collaboration between hepatologists and rheumatologists can lead to significant advances in managing such a complex scenario. In this review, we provide a comprehensive overview on coexisting AILDs in different SRDs and the therapeutic approach in managing these overlap diseases.

Immunoglobulin G4-related autoimmune hepatitis simultaneously concomitant with autoimmune pancreatitis: a case report

Thus far, there have been limited case reports on immunoglobulin G4-related autoimmune hepatitis (IgG4-AIH), and its clinical features have not been elucidated. We herein report a rare case of IgG4-AIH simultaneously concomitant with autoimmune pancreatitis (AIP). A 73-year-old female was admitted to our hospital for further investigation of elevated levels of liver transaminase and pancreatic enzymes. Her serological tests showed a high antinuclear antibody titer, and elevated IgG and IgG4 levels. Liver biopsy revealed interface hepatitis and bridging necrosis with IgG4-positive lymphoplasmacytic infiltration in the portal area. Moreover, contrast-enhanced computed tomography (CECT) showed pancreatic tail enlargement, and magnetic resonance cholangiopancreatography showed skipped narrowing of the main pancreatic duct in the pancreatic tail. Endoscopic ultrasonography-fine needle aspiration specimens showed no malignant cells. Based on these results, we diagnosed her with IgG4-AIH simultaneously concomitant with probable type 1 AIP. She was started on prednisolone (PSL) at 35 mg/d, and her symptoms and liver transaminase levels improved. One month after starting treatment, CECT showed improvement of pancreatic tail enlargement. She is maintained on 5 mg PSL/d and has been in remission for two years.