Characteristic findings in images of extra-pancreatic lesions associated with autoimmune pancreatitis

IgG4-related sclerosing disease: autoimmune pancreatitis and extrapancreatic manifestations

Autoimmune pancreatitis is the pancreatic manifestation of IgG4-related sclerosing disease, which recently was recognized as a distinct disease entity. Numerous extrapancreatic organs, such as the bile ducts, gallbladder, kidneys, retroperitoneum, thyroid, salivary glands, lung, mediastinum, lymph nodes, and prostate may be involved, either synchronously or metachronously. Most cases of autoimmune pancreatitis are associated with elevated serum IgG4 levels; extensive IgG4-positive plasma cells; and infiltration of lymphocytes into various organs, which leads to fibrosis. There are several established diagnostic criteria systems that are used to diagnose autoimmune pancreatitis and that rely on a combination of imaging findings of the pancreas and other organs, serologic findings, pancreatic histologic findings, and response to corticosteroid therapy. It is important to recognize multiorgan involvement of IgG4-related sclerosing disease and be familiar with its clinical and imaging features because it demonstrates a favorable response to treatment.

Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011

BACKGROUND

IgG4-related disease (IgG4-RD) is a novel clinical disease entity characterized by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4+ plasma cells. Although IgG4-RD is not rare and is clinically important, its clinical diagnostic criteria have not been established. Comprehensive diagnostic criteria for IgG4-RD, including the involvement of various organs, are intended for the practical use of general physicians and nonspecialists.

METHODS

Two IgG4-RD study groups, the Umehara and Okazaki teams, were organized by the Ministry of Health, Labor and Welfare Japan. As IgG4-RD comprises a wide variety of diseases, these groups consist of physicians and researchers in various disciplines, including rheumatology, hematology, gastroenterology, nephrology, pulmonology, ophthalmology, odontology, pathology, statistics, and basic and molecular immunology throughout Japan, with 66 and 56 members of the Umehara and Okazaki teams, respectively. Collaborations of the two study groups involved detailed analyses of clinical symptoms, laboratory results, and biopsy specimens of patients with IgG4-RD, resulting in the establishment of comprehensive diagnostic criteria for IgG4-RD.

RESULTS

Although many patients with IgG4-RD have lesions in several organs, either synchronously or metachronously, and the pathological features of each organ differ, consensus has been reached on two diagnostic criteria for IgG4RD: (1) serum IgG4 concentration >135 mg/dl, and (2) >40% of IgG+ plasma cells being IgG4+ and >10 cells/high powered field of biopsy sample. Although the comprehensive diagnostic criteria are not sufficiently sensitive for the diagnosis of type 1 IgG4-related autoimmune pancreatitis (IgG4-related AIP), they are adequately sensitive for IgG4-related Mikulicz's disease (MD) and kidney disease (KD). In addition, the comprehensive diagnostic criteria, combined with organ-specific diagnostic criteria, have increased the sensitivity of diagnosis to 100% for IgG4-related MD, KD, and AIP.

CONCLUSION

Our comprehensive diagnostic criteria for IgG4-RD are practically useful for general physicians and nonspecialists.

Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011

BACKGROUND

IgG4-related disease (IgG4-RD) is a novel clinical disease entity characterized by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4+ plasma cells. Although IgG4-RD is not rare and is clinically important, its clinical diagnostic criteria have not been established. Comprehensive diagnostic criteria for IgG4-RD, including the involvement of various organs, are intended for the practical use of general physicians and nonspecialists.

METHODS

Two IgG4-RD study groups, the Umehara and Okazaki teams, were organized by the Ministry of Health, Labor and Welfare Japan. As IgG4-RD comprises a wide variety of diseases, these groups consist of physicians and researchers in various disciplines, including rheumatology, hematology, gastroenterology, nephrology, pulmonology, ophthalmology, odontology, pathology, statistics, and basic and molecular immunology throughout Japan, with 66 and 56 members of the Umehara and Okazaki teams, respectively. Collaborations of the two study groups involved detailed analyses of clinical symptoms, laboratory results, and biopsy specimens of patients with IgG4-RD, resulting in the establishment of comprehensive diagnostic criteria for IgG4-RD.

RESULTS

Although many patients with IgG4-RD have lesions in several organs, either synchronously or metachronously, and the pathological features of each organ differ, consensus has been reached on two diagnostic criteria for IgG4RD: (1) serum IgG4 concentration >135 mg/dl, and (2) >40% of IgG+ plasma cells being IgG4+ and >10 cells/high powered field of biopsy sample. Although the comprehensive diagnostic criteria are not sufficiently sensitive for the diagnosis of type 1 IgG4-related autoimmune pancreatitis (IgG4-related AIP), they are adequately sensitive for IgG4-related Mikulicz's disease (MD) and kidney disease (KD). In addition, the comprehensive diagnostic criteria, combined with organ-specific diagnostic criteria, have increased the sensitivity of diagnosis to 100% for IgG4-related MD, KD, and AIP.

CONCLUSION

Our comprehensive diagnostic criteria for IgG4-RD are practically useful for general physicians and nonspecialists.

Type 1 autoimmune pancreatitis

Before the concept of autoimmune pancreatitis (AIP) was established, this form of pancreatitis had been recognized as lymphoplasmacytic sclerosing pancreatitis or non-alcoholic duct destructive chronic pancreatitis based on unique histological features. With the discovery in 2001 that serum IgG4 concentrations are specifically elevated in AIP patients, this emerging entity has been more widely accepted. Classical cases of AIP are now called type 1 as another distinct subtype (type 2 AIP) has been identified. Type 1 AIP, which accounts for 2% of chronic pancreatitis cases, predominantly affects adult males. Patients usually present with obstructive jaundice due to enlargement of the pancreatic head or thickening of the lower bile duct wall. Pancreatic cancer is the leading differential diagnosis for which serological, imaging, and histological examinations need to be considered. Serologically, an elevated level of IgG4 is the most sensitive and specific finding. Imaging features include irregular narrowing of the pancreatic duct, diffuse or focal enlargement of the pancreas, a peri-pancreatic capsule-like rim, and enhancement at the late phase of contrast-enhanced images. Biopsy or surgical specimens show diffuse lymphoplasmacytic infiltration containing many IgG4⁺ plasma cells, storiform fibrosis, and obliterative phlebitis. A dramatic response to steroid therapy is another characteristic, and serological or radiological effects are normally identified within the first 2 or 3 weeks. Type 1 AIP is estimated as a pancreatic manifestation of systemic IgG4-related disease based on the fact that synchronous or metachronous lesions can develop in multiple organs (e.g. bile duct, salivary/lacrimal glands, retroperitoneum, artery, lung, and kidney) and those lesions are histologically identical irrespective of the organ of origin. Several potential autoantigens have been identified so far. A Th2-dominant immune reaction and the activation of regulatory T-cells are assumed to be involved in the underlying immune reaction. IgG4 antibodies have two unique biological functions, Fab-arm exchange and a rheumatoid factor-like activity, both of which may play immune-defensive roles. However, the exact role of IgG4 in this disease still remains to be clarified. It seems important to recognize this unique entity given that the disease is treatable with steroids.

Whole-body gallium-67 scintigraphic findings in IgG4-related disease

PURPOSE

To clarify the features of gallium-67 (Ga-67) imaging typical of IgG4-related disease.

METHODS

We retrospectively investigated 14 patients diagnosed with IgG4-related disease who underwent Ga-67 scintigraphy in our hospital between January 2005 and May 2010. Of these, 13 patients who underwent gallium scintigraphy before steroid therapy were enrolled in this study. The patient population comprised 11 men and 2 women with age ranging from 47 to 76 years (mean age, 61.9 years).

RESULTS

Among the 13 patients, significant accumulation of Ga-67 was detected in the bilateral pulmonary hila in 10 patients (77%), pancreas in 10 (77%), salivary glands in 7 (54%), lacrimal glands in 7 (54%), periaortic lesions in 2 (15%), and lung parenchyma in 1 (8%) patient. High accumulation of Ga-67 in the salivary glands was observed in the parotid glands in 3 cases and in the submandibular glands in 6 cases, with the following pattern: normal parotid gland uptake and symmetrical submandibular gland uptake in 2 cases; symmetrical high accumulation in both parotid and submandibular glands in 1 case; symmetrical high accumulation in parotid glands and normal submandibular gland uptake in 1 case; symmetrical uptake by parotid glands and asymmetric uptake by submandibular glands in 1 case; normal parotid gland uptake and asymmetric submandibular gland uptake in 1 case; and asymmetric parotid gland uptake and symmetrical parotid gland uptake in 1 case.

CONCLUSION

Characteristic patterns of gallium uptake would be helpful for diagnosis, detection of involved lesions, and differential diagnosis in patients with IgG4-related disease to avoid unnecessary surgery.

Proposal for diagnostic criteria for IgG4-related kidney disease

BACKGROUND

IgG4-related disease has attracted wide attention recently. It is characterized by a high level of serum IgG4 and dense infiltration of IgG4-positive plasma cells into multiple organs, with the kidney being one representative target. Although several sets of diagnostic criteria for autoimmune pancreatitis (AIP) are available and renal lesion is recognized as an extra-pancreatic manifestation of AIP, it is difficult to differentiate IgG4-related tubulointerstitial nephritis (TIN) without AIP from other types of TIN. To clarify the entity of IgG4-related kidney disease (IgG4-RKD) and support in-depth studies, the Japanese Society of Nephrology has established a working group to prepare diagnostic criteria for IgG4-RKD.

METHOD

The working group analyzed 41 patients with IgG4-RKD, and collected the following data to devise a diagnostic algorithm and diagnostic criteria for IgG4-RKD: clinical features including extra-renal organ involvement, urinalysis and serological features including serum IgG4 levels, imaging findings demonstrated by computed tomography (CT), renal histology with IgG4 immunostaining, and response to steroid therapy.

RESULTS

The conditions for criteria are as follows. (1) Presence of some kidney damage, as manifested by abnormal urinalysis or urine marker(s) and/or decreased kidney function with either elevated serum IgG level, hypocomplementemia, or elevated serum IgE level. (2) Kidney imaging studies showing abnormal renal imaging findings, i.e., multiple low density lesions on enhanced CT, diffuse kidney enlargement, hypovascular solitary mass in the kidney, and hypertrophic lesion of the renal pelvic wall without irregularity of the renal pelvic surface. (3) Serum IgG4 level exceeding 135 mg/dl. (4) Renal histology showing two abnormal findings: (a) dense lymphoplasmacytic infiltration with infiltrating IgG4-positive plasma cells >10/high power field (HPF) and/or ratio of IgG4-positive plasma cells/IgG positive plasma cells >40%. (b) Characteristic 'storiform' fibrosis surrounding nests of lymphocytes and/or plasma cells. (5) Extra-renal histology showing dense lymphoplasmacytic infiltration with infiltrating IgG4-positive plasma cells >10/HPF and/or ratio of IgG4-positive plasma cells/IgG-positive plasma cells >40%. The diagnosis is classified into 3 stages of definite, probable and possible according to the combinations of the above conditions. Thirty-nine cases (95.1%) were diagnosed with IgG4-RKD according to the criteria.

CONCLUSION

The provisional criteria and algorithm appear to be useful for clarifying the entity of IgG4-RKD and seeking underlying IgG4-RKD cases; however, further experience is needed to confirm the validity of these criteria.

Respiratory involvement in IgG4-related Mikulicz's disease

'Immunoglobulin G4 (IgG4)-related disease' is a new clinical concept of multi-organ diseases, with Mikulicz's disease (MD) being a clinical phenotype of IgG4-related disease. To clarify the clinical characteristics of respiratory involvement associated with IgG4-related MD, we retrospectively assessed 25 patients with MD, 11 (44%) of whom had allergic symptoms, and 7 (28%) of whom complained of respiratory problems. Thirteen patients (52%) presented with pulmonary and/or mediastinal lesions (P-MD) on chest computed tomography (CT), and 11 (44%) had lesions limited to the lacrimal and/or salivary glands (L-MD). Mean serum total protein, IgG, and IgG4 concentrations were significantly higher and CH50 was significantly lower in the P-MD than in the L-MD group. Immune complex was present only in the P-MD group. Chest CT images showed bronchial wall thickening, consolidation, nodule(s), interlobular thickening, ground glass opacity, pleural thickening/effusion, and mediastinal lymphadenopathy. Five of seven patients who underwent histological examination of the lungs had abundant IgG4-positive plasma cell infiltrates (IgG4/IgG-positive plasma cells >40%), but the other two did not. These findings suggest that respiratory lesions are not rare in patients with IgG4-related MD, and that they present with various manifestations. IgG4-related MD should be differentiated from similar diseases, such as sarcoidosis, bronchial asthma, Sjögren's syndrome, and malignant lymphoma.

Infraorbital nerve swelling associated with autoimmune pancreatitis

PURPOSE

The aim of our study was to examine the relation between autoimmune pancreatitis (AIP) and infraorbital nerve swelling.

MATERIALS AND METHODS

A total of 11 AIP patients underwent magnetic resonance imaging (MRI) examination of the head and neck region. The infraorbital nerve thicknesses were measured on coronal images and compared with those of a control group. We also examined whether the infraorbital nerve thicknesses were altered from before to after steroid therapy in nine patients who underwent MRI examination after such therapy.

RESULTS

The mean thicknesses were 3.8 ± 2.0 mm in the AIP group and 2.6 ± 0.5 mm in the control group (P < 0.05). The nerve thicknesses were >5 mm in 5 of 11 patients (45%) in the AIP group, and <5 mm in all of the control group. Among the nine patients who underwent MRI examination after steroid therapy, three had shown nerve swelling before steroid therapy; the therapy diminished the swelling in all three patients.

CONCLUSION

Infraorbital nerve swelling was observed more frequently in AIP patients than in patients without a history of AIP. Therefore, such swelling seems to be an extrapancreatic lesion of AIP.

Review article: autoimmune pancreatitis - management of an emerging disease

BACKGROUND

Autoimmune pancreatitis is a steroid-responsive inflammatory pancreatic disease considered to be part of an immunoglobulin G4 (IgG4)-associated systemic disease.

AIM

To review the management of autoimmune pancreatitis.

METHODS

We conducted a PubMed search using the following key words: autoimmune pancreatitis, IgG4-associated systemic disease, IgG4-associated cholangitis, diagnosis, natural history, treatment.

RESULTS

Although there are reports of spontaneous resolution of autoimmune pancreatitis, steroids have been shown to be effective in inducing remission, reducing the frequency of relapse and that of long-term unfavourable events compared to historical controls. There are no randomised data on autoimmune pancreatitis treatment. Oral steroids are used for induction of remission. Reported response results are excellent with variable proportions of patients achieving remission in different studies. After a period of 2-4 weeks, steroids are tapered and usually withdrawn within several months, although long-term maintenance therapy for all autoimmune pancreatitis patients has also been proposed. Disease relapse occurs in more than 40% of patients and can be effectively treated with additional immunosuppression, including azathioprine.

CONCLUSIONS

Steroids are effective in inducing remission and in treating relapse in patients with autoimmune pancreatitis. Randomised trials on autoimmune pancreatitis therapy are lacking. To date, questions concerning the timing, choice and duration of long-term immunosuppression remain unanswered.

IgG4-related airway involvement which developed in a patient receiving corticosteroid therapy for autoimmune pancreatitis

A 66-year-old man was diagnosed with autoimmune pancreatitis in February 2009 and started 40 mg of oral prednisolone followed by a maintenance dose of 5 mg daily. The patient developed a cough in October 2010 and visited our division. He had a high serum concentration of immunoglobulin (Ig) G4 and his chest computed tomography showed airway stenosis without bilateral hilar lymphadenopathy (BHL). The bronchial biopsy specimens revealed lymphoplasmacytic infiltrations with IgG4-positive/IgG-positive plasma cells of more than 50%. Thus, we diagnosed the airway lesion with IgG4-related airway involvement. This is the first report of a patient with IgG4-related airway involvement without BHL.

IgG4-related pleural disease diagnosed by a re-evaluation of chronic bilateral pleuritis in a patient who experienced occasional acute left bacterial pleuritis

A 78-year-old man with cryptogenic chronic bilateral lymphoplasmacytic pleuritis, diagnosed based on left parietal pleural biopsy specimens obtained by pleuroscopy, developed acute left bacterial pleuritis. The left pleural effusion was neutrophil dominant, however, the right pleural effusion showed lymphoplasmacytic infiltration. Laboratory examinations revealed that his serum IgG4 concentration was increased, with a higher level of IgG4 in the right pleural effusion. Re-evaluation of the previous biopsy specimens using an immunostaining method revealed numerous IgG4-positive plasma cell infiltrations with IgG4-positive/IgG-positive plasma cells at 85.4%. Accordingly, the new diagnosis of this patient was considered to be chronic bilateral IgG4-related pleuritis.