Autoimmune pancreatitis — a surgical disease?

Abstract

The term autoimmune pancreatitis (AIP) describes a nonalcoholic, chronic lymphoplasmocytic pancreatitis. The lymphoplasmocytic infiltration is characterized by periductal localization of predominantly CD4-positive T cells, fibrosis, and acinar atrophy, frequently resulting in stenosis of the main pancreatic and distal common bile ducts. Imaging studies often reveal a diffuse narrowing of the pancreatic main duct and swelling of the pancreatic head wrongly suggesting the presence of a malignant tumor. Clinical signs include mild abdominal pain, jaundice, recurrent episodes of acute pancreatitis, and even new-onset diabetes mellitus. Additionally, AIP can be associated with other autoimmune diseases such as Sjögren's syndrome, primary sclerosing cholangitis, chronic inflammatory bowel diseases, and retroperitoneal fibrosis. Serological markers include autoantibodies and increased levels of gamma globulin and especially IgG4. Steroids seem to be effective in improving clinical symptoms as well as in the resolution of pancreatic and bile duct narrowing. This distinguishes AIP from other forms of pancreatitis and from pancreatic neoplasms. Further studies of the underlying pathophysiologic mechanisms, prognosis, and new diagnostic tools are needed to provide adequate and effective treatment in the future. In this article, we summarize the current knowledge about AIP and present 17 cases that underwent surgical resection at our institution from 2003 to 2004.

Autoimmune pancreatitis

“…Nahon et al [52] from France reported IgG4 positivity in only 20% of their cases. In a series from Mannheim/Heidelberg, the frequency was only around 20% positivity for any autoimmune serological phenomenon despite clear histological evidence of AIP [13]. Therefore, as for other forms of CP, the search for a trustful marker is still ongoing [53].…”

“…It is interesting to note that the relative frequency of the two AIP subtypes in Europe and the USA seems to differ from that in East Asia. While in Europe each subtype can be expected in about 40-50% of cases, the GEL-positive AIP subtype seems to be rare in East Asia [10,13,14,27,[50][51][52][53]90,92]. While the analysis of pancreatic core needle biopsies for the diagnosis of AIP in most studies was based on the presence of (periductal) lymphoplasmacytic inflammation, infiltration of IgG4-positive plasma cells, cellular fibrosis and/or venulitis, GELs and infiltration of eosinophilic granulocytes should also be taken into account [27,[93][94][95][96].…”

“…In the revised version, it is specifically stated that the histological criteria can also be used when observed in a pancreatic core needle biopsy specimen and not exclusively in a pancreatic resection specimen [18]. European groups have also defined criteria, which include the possibility to diagnose AIP by histology alone or by combinations of imaging features, serology, other organ involvement and trial with steroids [10,13]. Hence, the diagnosis of AIP can be established on the basis of characteristic radiologic findings, abnormal laboratory tests and histological features, and sometimes also due to recognition of the involvement of other organs and the response to a diagnostic trial with steroids [18,19,67].…”

“…Clinically, AIP patients complain of abdominal pain, anorexia and jaundice, and in a subgroup of patients other autoimmune diseases are present [11][12][13]. However, the pain in AIP is normally less intense than in alcoholic CP.…”

Autoimmune Pancreatocholangitis, Non-Autoimmune Pancreatitis and Primary Sclerosing Cholangitis: A Comparative Morphological and Immunological Analysis

“…Autoantibodies against lactoferrin or carbonic anhydrase isozymes are present in subgroups of AIPC patients [12], [13] and elevated carbonic anhydrase II autoantibodies are associated with increased serum IgG4 levels [14]. The clinical and serological features of AIPC are far from being uniform, so that a preoperative diagnosis is difficult and most patients are still subjected to probably unnecessary surgery [15]. Elevated serum levels of IgG4 have been reported to be of diagnostic value in some series,[16], [17] whereas other groups have shown that a mild (≤2-fold) elevation of IgG4 levels can also occur in other settings, such as non-autoimmune chronic pancreatitis and pancreatic cancer [18].…”