The degree of mucosal damage to the small intestine and serum immunoglobulin G4 levels correlate with celiac disease

Immunoglobulin G4 in primary Sjögren's syndrome and IgG4-related disease - connections and dissimilarities

Primary Sjögren's syndrome (pSS) is an autoimmune disease, with B cell hyperactivation and autoantibody production as its immunological hallmarks. Although the distinction between immunoglobulin G4-related disease (IgG4-RD) and pSS, based on the presence or absence of certain autoantibodies, seems easy to make, possibility of elevated serum IgG4 concentration and often similar organ involvement may lead to a misdiagnosis. The increased serum concentration of IgG4 in IgG4-RD is not clearly linked to the pathogenesis of IgG-RD and it has been suggested that it may constitute just an epiphenomenon. The aim of this article is to discuss the presence of IgG4 in pSS and IgG4-RD and its potential significance for these two diseases.

A Clinical and Pathophysiological Overview of Intestinal and Systemic Diseases Associated with Pancreatic Disorders: Causality or Casualty?

The relationship between chronic intestinal disease, including inflammatory bowel disease (IBD) and celiac disease (CelD), and pancreatic disorders has been little investigated. Although an increased risk of acute pancreatitis (AP), exocrine pancreatic insufficiency with or without chronic pancreatitis, and chronic asymptomatic pancreatic hyperenzymemia have been described in these patients, the pathogenetic link remains unclear. It may potentially involve drugs, altered microcirculation, gut permeability/motility with disruption of enteric-mediated hormone secretion, bacterial translocation, and activation of the gut-associated lymphoid tissue related to chronic inflammation. In addition, the risk of pancreatic cancer seems to be increased in both IBD and CelD patients with unknown pathogenesis. Finally, other systemic conditions (e.g., IgG4-related disease, sarcoidosis, vasculitides) might affect pancreatic gland and the intestinal tract with various clinical manifestations. This review includes the current understandings of this enigmatic association, reporting a clinical and pathophysiological overview about this topic.

Gastrointestinal manifestation of immunoglobulin G4-related disease: clarification through a multicenter survey

BACKGROUND

Several reports on immunoglobulin (Ig)G4-related disease (IgG4-RD) with gastrointestinal involvement (IgG4-related gastrointestinal disease; IgG4-GID) have been published, although this entity has not been fully established clinicopathologically. Thus, we carried out a multicenter survey.

METHODS

Patients with possible IgG4-GID who underwent resection were collected. Histologic slides were reevaluated, and eight cases with diffuse lymphoplasmacytic infiltration but without numerous neutrophils, granulations or epithelioid granulomas were further analyzed.

RESULTS

Overall, the IgG4 counts (87-345/high-power field) and IgG4/IgG-positive ratio were high (44-115%). The demographic findings included advanced age among the patients (55-80 years) and male preponderance (six cases). Six lesions (five gastric, one esophageal), consisting of lymphoplasmacytic infiltration with neural involvement in the muscularis propria and/or bottom-heavy plasmacytosis in the gastric mucosa, were histologically regarded as highly suggestive of IgG4-RD. Storiform fibrosis and obliterative phlebitis were found in two cases, and the former gave rise to a 7-cm-sized inflammatory pseudotumor (IPT) in one case. Ulceration and carcinoma co-existed in three and two lesions, respectively. All the patients had other organ involvement (OOI), and serum IgG4 levels were markedly elevated (four of five patients). The remaining two cases with gastric IPTs featuring reactive nodular fibrous pseudotumor or nodular lymphoid hyperplasia were regarded as possible cases of IgG4-RD because of the histologic findings and lack of OOI.

CONCLUSIONS

IgG4-GID is found in the setting of IgG4-RD, often with ulceration or cancer. Characteristic histologic findings are observed in the muscularis propria and gastric mucosa. Cases with IPT may be heterogeneous, and there may be mimickers of IgG4-GID.