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

The utility of FDG-PET/CT and other imaging techniques in the evaluation of IgG4-related disease

OBJECTIVES

This study aimed to evaluate the utility of imaging techniques, including 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), in immunoglobulin (IgG)4-related disease (IgG4-RD).

METHODS

We reviewed eight IgG4-RD patients who were referred to our hospital between August 2006 and April 2012. All cases underwent FDG-PET/CT and brain magnetic resonance imaging (MRI) and endobronchial ultrasonography (EBUS) were also performed in five cases and one case, respectively.

RESULTS

Although nearly all patients with IgG4-RD in this study were negative for CRP (mean 0.22 mg/dL), various organ involvement sites were detected by FDG-PET/CT. In the active phase in two autoimmune pancreatitis (AIP) cases, FDG-PET/CT showed longitudinal and heterogeneous FDG accumulation in the pancreas with FDG uptake in the hilar or mediastinal lymph nodes. Follow-up FDG-PET/CT after therapy in one case revealed that the abnormal FDG uptake in all affected lesions had completely disappeared. In two cases, brain MRI revealed asymptomatic hypertrophic pachymeningitis. In one case, EBUS imaging of mediastinal lymph node swelling was consistent with tortuous vessels with high Doppler signals and hyperechoic strands between lymph nodes.

CONCLUSIONS

When FDG-PET/CT shows FDG accumulation, characteristic of IgG4-RD in organs, without evidence of an associated inflammatory reaction, a diagnosis of IgG4-RD can be made. Treatment effects can be assessed by the disappearance of FDG uptake. A routine brain MRI is useful for detecting asymptomatic hypertrophic pachymeningitis. EBUS may also be useful for differentiating among the etiologies of lymphadenopathy with characteristic sonographic imaging findings.

Description of patients with IgG4-related disease from a Hungarian centre

OBJECTIVES

Although most reported patients with immunoglobulin G4-related disease (IgG4-RD) are from the Far East, we aimed to identify patients suffering from IgG4-RD in our University Centre in Debrecen, Hungary.

METHOD

Serum IgG4 levels were measured at 51 of our 800 patients followed up because of Sjögren's syndrome (SS) if one or more clinical signs during the disease course raised the possibility of IgG4-RD (persisting salivary gland swelling, absence of anti-Ro/SSA and anti-La/SSB antibodies in the serum, and positive salivary gland biopsy, coexistence of autoimmune pancreatitis, autoimmune hepatitis, or primary sclerosing cholangitis, persisting lymphadenopathy). Where available, histological samples of small salivary gland biopsies were revised to detect the particular features of IgG4-RD. Pathologists and surgeons were informed about the disease and asked to refer suspicious cases.

RESULTS

Based on our survey, eight patients were identified with IgG4-RD. Pancreatic, salivary gland, aortic, and retroperitoneal manifestations were detected. Of the 51 patients with SS, four appeared to have IgG4-RD, but eventually one was excluded.

CONCLUSIONS

Although IgG4-RD is not yet well known to physicians of Western countries, it occurs in Caucasians and probably in other races as well. Moreover, our eight cases diagnosed with IgG4-RD demonstrate a relatively large European patient population collected in a single centre. European clinicians, and especially rheumatologists, should be informed and at least certain laboratories should be prepared to investigate patient samples if the suspicion of IgG4-RD is raised. The main clinical significance of an accurate diagnosis is the extreme corticosteroid sensitivity of IgG4-RD.

The prevalence of IgG4-related hypophysitis in 170 consecutive patients with hypopituitarism and/or central diabetes insipidus and review of the literature

OBJECTIVE

The prevalence and clinical characteristics of IgG4-related hypophysitis remain unclear due to the limited number of case reports. Therefore, in this study, we screened consecutive outpatients with hypopituitarism and/or diabetes insipidus (DI) to estimate its prevalence.

METHODS

A total of 170 consecutive outpatients with hypopituitarism and/or central DI were screened at Kobe University Hospital for detecting IgG4-related hypophysitis by pituitary magnetic resonance imaging, measuring serum IgG4 concentrations, assessing the involvement of other organs, and carrying out an immunohistochemical analysis to detect IgG4-positive cell infiltration.

RESULTS

Among the screened cases, 116 cases were excluded due to diagnosis of other causes such as tumors and congenital abnormalities. Additionally, 22 cases with isolated ACTH deficiency were analyzed and were found not to meet the criteria of IgG4-related hypophysitis. The remaining 32 cases were screened and seven were diagnosed with IgG4-related hypophysitis, of which three cases were diagnosed by analyzing pituitary specimens. IgG4-related hypophysitis was detected in 30% (seven of 23 patients) of hypophysitis cases and 4% of all hypopituitarism/DI cases. The mean age at the onset of IgG4-related hypophysitis was 61.8±8.8 years, and the serum IgG4 concentration was 191.1±78.3 mg/dl (normal values 5-105 mg/dl and values in IgG4-related disease (RD) ≥135 mg/dl). Pituitary gland and/or stalk swelling was observed in six patients, and an empty sella was observed in one patient. Multiple co-existing organ involvement was observed in four of the seven patients prior to the onset of IgG4-related hypophysitis.

CONCLUSION

These data suggest that the prevalence of IgG4-related hypophysitis has been underestimated. We should also consider the possibility of the development of hypopituitarism/DI caused by IgG4-related hypophysitis during the clinical course of other IgG4-RDs.

Orbital Manifestations of Immunoglobulin G4-Related Disease in Bilateral Lacrimal Glands, Optic Nerves, Trigeminal Nerves, and Maxillary Sinuses

Immunoglobulin G4 (IgG4)-related disease is characterised by numerous aggregates of IgG4-positive plasma cells in multiple organs. We report two patients who had bilateral proptosis associated with extensive inflammation bilaterally in lacrimal glands, optic nerves, trigeminal nerves, and maxillary sinuses. The patients were treated as idiopathic orbital inflammation syndrome with corticosteroid pulse therapy. As symptoms relapsed upon tapering, a reassessment of immunohistochemical stains of the lacrimal glands confirmed the diagnosis of IgG4-related disease. During 2 years of follow-up, the inflammation regressed spontaneously without any medical treatment in the first patient; however, inflammation in the other patient progressed, and he lost his vision. The extensive orbital involvement, characteristic pathological findings, and slowly progressive clinical course might help practitioners differentiate orbital IgG4-related disease from presumed idiopathic orbital inflammation syndrome.

Radiographic patterns of orbital involvement in IgG4-related disease

PURPOSE

Immunoglobin G4 (IgG4)-related disease is a systemic condition characterized by lymphoplasmacytic infiltrates that can involve the orbit. The purpose of this study was to identify the various patterns of orbital IgG4-related disease on imaging.

METHODS

Retrospective review of radiologic examinations including CT, MRI, and positron emission tomography was performed in patients with proven cases of IgG4-related disease.

RESULTS

A total of 9 patients with orbital IgG4-related disease were identified, including 9 with CT, 4 with MRI, and 4 with 18-fluorodeoxyglucose positron emission tomography. Patterns of involvement included lacrimal gland enlargement, lacrimal sac involvement, extraocular muscle thickening, preseptal involvement, orbital fat involvement, and cranial nerve involvement, many of which occurred simultaneously. Associated demineralization of the orbital wall was evident on CT in 2 cases. On T2-weighted MRI, the lesions appeared as hypointense in 2 cases, heterogeneously hypointense to isointense in 1 case, and hyperintense in 1 case. Diffuse enhancement was present in all 3 cases in which postcontrast T1-weighted sequences were available. The lesions were hypermetabolic on positron emission tomography in 3 of 4 cases. There was definite extraorbital involvement by IgG4-related disease in 3 of the 9 patients and suspected involvement in another 3 of the 9 patients.

CONCLUSIONS

IgG4-related disease displays a wide variety of imaging manifestations in the orbit. Extraorbital disease is often present and can help suggest the diagnosis.

Diagnosis and classification of autoimmune pancreatitis

Recent studies suggested the existence of two subtypes of autoimmune pancreatitis (AIP): type 1 related with IgG4 as the pancreatic manifestation of IgG4-related disease (IgG4-RD), and type 2 related with a granulocytic epithelial lesion. Apart from type 2 AIP, the characteristic features of type 1 AIP are increased serum IgG4 levels, lymphoplasmacytic sclerosing pancreatitis (abundant infiltration of IgG4+ plasmacytes and lymphocytes, storiform fibrosis, and obliterative phlebitis), extra-pancreatic manifestations of IgG4-RD (e.g. sclerosing cholangitis, sclerosing sialadenitis, retroperitoneal fibrosis), and steroid responsiveness. Although the way how to diagnose IgG4-RD has not been established yet, the Comprehensive Diagnostic Criteria (CDC) for IgG4-RD for general use, and several organ specific criteria for AIP have been proposed; the International Consensus Diagnostic Criteria (ICDC) and the revised clinical diagnostic criteria in 2011 by Japan Pancreas Society (JPS-2011) for type1 AIP. In cases of probable or possible IgG4-RD diagnosed by the CDC, organ specific diagnostic criteria should be concurrently used according to an algorithm of diagnosis for IgG4-RD with reference to the specialist.

Location and frequency of lesions in patients with IgG4-related ophthalmic diseases

BACKGROUND

It is well-known that the lacrimal gland (LG) may be affected in IgG4-related ophthalmic disease (IgG4ROD). Recently, IgG4-related ophthalmic lesions other than those of the lacrimal gland have been reported. However, no study to date has revealed the details of these lesions. This study was conducted to evaluate the location and frequency of lesions found in conjunction with IgG4ROD using radiological imaging.

METHODS

Radiological images and clinical records of 65 patients collected from seven institutions in Japan were reviewed retrospectively. All patients had been pathologically diagnosed with IgG4ROD. Patients of mucosa-associated lymphoid tissue lymphoma associated with IgG4-related lesions were excluded. Orbital magnetic resonance imaging or computed tomography findings were evaluated.

RESULTS

Of the 65 patients, 31 (47.7 %) had lesions involving the LG alone, whereas 34 (52.3 %) had lesions involving the areas other than LG, including eight patients who had lesions without any LG involvement. IgG4-related ophthalmic lesions included LG enlargement in 57 patients (87.7 %), trigeminal nerve branch enlargement in 25 (38.5 %), extraocular muscle enlargement in 16 (24.6 %), diffuse orbital fat lesions in 15 (23.1 %), orbital mass lesions in 11 (16.9 %), eyelid lesions in eight (12.3 %), and nasolacrimal duct lesion in one (1.5 %). Six patients (9.2 %) presented with visual disturbance due to optic nerve disturbance, eight (12.3 %) with a restriction of ocular movement, and 19 (29.2 %) with exophthalmos.

CONCLUSIONS

Thirty-four (52.3 %) of the 65 IgG4ROD patients had lesions in areas other than LG. Lesions were found in the trigeminal nerve branch including pterygopalatine fossa, extraocular muscles, orbital fat, eyelid, and nasolacrimal duct.

Prednisolone markedly reduced serum IgG4 levels along with the improvement of pituitary mass and anterior pituitary function in a patient with IgG4-related infundibulo-hypophysitis

In 2011 a 76 year-old man with a medical history of diabetes, hypertension and autoimmune pancreatitis was admitted to our hospital because of anorexia, general malaise and repeated hypoglycemia. When he was 72 years old, he suffered from pancreatitis, and pancreas head tumor was operated. IgG4-related pancreatitis was diagnosed histopathologically. On admission anterior pituitary function test revealed impaired response of ACTH and cortisol to CRH, and no response of GH, TSH and gonadotropin to GHRH, TRH and LHRH, respectively. Baseline PRL level was elevated. Serum IgG and IgG4 levels were markedly elevated. Pituitary MRI showed significant enlargement of pituitary gland and stalk. Chest CT suggested IgG4-related lung disease. IgG4-related infundibulo-hypophysitis was diagnosed based on the above mentioned past history and results of present examinations. Twenty mg of hydrocortisone, followed by 20 mg of prednisolone (PSL) and 25 μg of levothyroxine markedly reduced serum IgG4 levels and ameliorated the symptom, the size of pituitary and stalk, and anterior pituitary function (TSH, GH and gonadotropin), although diabetes insipidus became apparent due to glucocorticoid administration. This is a typical case of IgG4-related hypophysitis in which PSL causes marked improvement of pituitary mass and pituitary function along with the reduction of serum IgG4 levels.

Mechanisms and assessment of IgG4-related disease: lessons for the rheumatologist

Recognition of IgG4-related disease as an independent chronic inflammatory disorder is a relatively new concept; previously, the condition was thought to represent a subtype of Sjögren's syndrome. IgG4-related disease is characterized by elevated serum levels of IgG4 and inflammation of various organs, with abundant infiltration of IgG4-bearing plasma cells, storiform fibrosis and obliterative phlebitis representing the major histopathological features of the swollen organs. The aetiology and pathogenesis of this disorder remain unclear, but inflammation and subsequent fibrosis occur due to excess production of type 2 T-helper-cell and regulatory T-cell cytokines. The disease can comprise various organ manifestations, such as dacryoadenitis and sialadenitis (also called Mikulicz disease), type 1 autoimmune pancreatitis, kidney dysfunction and lung disease. Early intervention using glucocorticoids can improve IgG4-related organ dysfunction; however, patients often relapse when doses of these agents are tapered. The disease has also been associated with an increased incidence of certain malignancies. Increased awareness of IgG4-related disease might lead to consultation with rheumatologists owing to its clinical, and potentially pathogenetic, similarities with certain rheumatic disorders. With this in mind, we describe the pathogenic mechanisms of IgG4-related disease, and outline considerations for diagnosis and treatment of the condition.

Immunoglobulin g4 non-related sclerosing disease with intracardiac mass mimicking mitral stenosis: case report

The cardiovascular system may be one of the target organs of both immunoglobulin G4 related and non-related systemic multifocal fibrosclerosis. We present a case of IgG4 non-related systemic multifocal fibrosclerosis mimicking mitral stenosis on echocardiography. For a more detailed differential diagnosis, we used multimodal imaging techniques. After surgical biopsy around the abdominal aortic area in the retroperitoneum, histological examination revealed IgG4 non-related systemic multifocal fibrosclerosis. We describe the multimodal imaging used to diagnose IgG4 non-related systemic multifocal fibrosclerosis and a positive response to steroid treatment. There have been no previous case reports of IgG4 non-related systemic multifocal fibrosclerosis with intracardiac involvement. Here, we report a case of IgG4 non-related systemic multifocal fibrosclerosis mimicking mitral stenosis.

Mikulicz's disease. A case report

CASE REPORT

We report the case of a 48 year-old male with bilateral involvement of the salivary and lacrimal glands, which was diagnosed as Mikulicz's disease by incisional biopsy of the affected lacrimal glands, which was completely resolved after corticosteroid treatment.

DISCUSSION

Sclerosing sialadenitis and/or dacryoadenitis are chronic inflammatory diseases that are currently classified into IgG4-related diseases. Specifically, Mikulicz's disease is defined by a persistent and symmetrical swelling of the lacrimal and salivary glands together with elevated serum concentration of IgG4 and tissue infiltration by IgG4 (+) plasma cells.

Hypertrophic pachymeningitis: significance of myeloperoxidase anti-neutrophil cytoplasmic antibody

The aim of this study was to elucidate the characteristics, pathogenesis and treatment strategy of hypertrophic pachymeningitis that is associated with myeloperoxidase anti-neutrophil cytoplasmic antibody (ANCA). We retrospectively investigated clinical, radiological, immunological and pathological profiles of 36 patients with immune-mediated or idiopathic hypertrophic pachymeningitis, including 17 patients with myeloperoxidase-ANCA, four patients with proteinase 3-ANCA, six patients with other immune-mediated disorders, and nine patients with 'idiopathic' variety. Myeloperoxidase-ANCA-positive hypertrophic pachymeningitis was characterized by: (i) an elderly female predominance; (ii) 82% of patients diagnosed with granulomatosis with polyangiitis (previously known as Wegener's granulomatosis) according to Watts' algorithm; (iii) a high frequency of patients with lesions limited to the dura mater and upper airways, developing headaches, chronic sinusitis, otitis media or mastoiditis; (iv) a low frequency of patients with the 'classical or generalized form' of granulomatosis with polyangiitis involving the entire upper and lower airways and kidney, or progressing to generalized disease, in contrast to proteinase 3-ANCA-positive hypertrophic pachymeningitis; (v) less severe neurological damage according to the modified Rankin Scale and low disease activity according to the Birmingham Vasculitis Activity Score compared with proteinase 3-ANCA-positive hypertrophic pachymeningitis; (vi) increased levels of CXCL10, CXCL8 and interleukin 6 in cerebrospinal fluids, and increased numbers of T cells, neutrophils, eosinophils, plasma cells and monocytes/macrophages in autopsied or biopsied dura mater with pachymeningitis, suggesting TH1-predominant granulomatous lesions in hypertrophic pachymeningitis, as previously reported in pulmonary or renal lesions of granulomatosis with polyangiitis; and (vii) greater efficacy of combination therapy with prednisolone and cyclophosphamide compared with monotherapy with prednisolone. Proteinase 3-ANCA may be considered a marker for more severe neurological damage, higher disease activity and a higher frequency of the generalized form compared with myeloperoxidase-ANCA-positive hypertrophic pachymeningitis. However, categorization into 'granulomatosis with polyangiitis' according to Watts' algorithm and immunological or pathological features were common in both proteinase 3- and myeloperoxidase-ANCA-positive hypertrophic pachymeningitis. These data indicate that most patients with myeloperoxidase-ANCA-positive hypertrophic pachymeningitis should be categorized as having the central nervous system-limited form of ANCA-associated vasculitis, consistent with the concept of ophthalmic-, pulmonary- or renal-limited vasculitis.

Immunoglobulin G4-related disease of the hard palate

A 71-year-old woman presented with erythematous, nontender, bilateral hard palate nodules of 6-month duration. Biopsy showed collagenous sclerosis and a follicular lymphoplasmacytic infiltrate among the minor salivary glands. Immunoglobulin G (IgG) and IgG4 staining showed 280 IgG4(+) cells per high-power field and a ratio of IgG4(+) to IgG(+) cells of 0.8. The patient subsequently developed bilateral lacrimal gland and parotid gland enlargement associated with an increased serum IgG4 level of 3,031 mg/dL (≤ 135 mg/dL). Left lacrimal gland biopsy confirmed IgG4-related dacryoadenitis. The patient declined corticosteroid treatment for IgG4-related disease (IgG4-RD) and remained stable at 15 months after the first presentation. Spontaneous, partial resolution of the palatal lesion was observed during follow-up. IgG4-RD should be considered in the differential diagnosis of lymphoplasmacytic lesions of the hard palate.

Ophthalmic manifestations of IgG4-related disease: single-center experience and literature review

OBJECTIVES

IgG4-related disease (IgG4-RD) is an inflammatory disorder responsible for fibrosing, tumefactive lesions that can involve the lacrimal gland as well as the extraocular muscles, orbital soft tissues, sclera, and local nerves. We reviewed IgG4-related ophthalmic disease (IgG4-ROD), including the natural history, pathology, and treatment, based on our center's experience and that reported in the literature.

METHODS

We identified 27 patients with orbital manifestations from our IgG4-RD registry; six were excluded because no pathology was available for review. All 21 cases included had histopathologically confirmed diagnoses of IgG4-RD, 11 of which were of the orbital tissue. Other data were obtained by a retrospective medical records review. MEDLINE and PubMed literature searches in English were conducted to identify articles for a literature review on the topic.

RESULTS

Patients with IgG4-ROD were predominantly male (57%) and had an average age at symptom onset of 50 years (range: 21-79 years). The lacrimal gland was the most commonly involved structure (62%). Most patients (71%) had bilateral disease and extra-orbital involvement (71%); these patients also had elevated serum IgG4 concentrations compared to those with unilateral disease and no extra-orbital disease. Ten patients improved following rituximab treatment.

CONCLUSIONS

Ophthalmic involvement is a common manifestation of IgG4-RD and can affect nearly every orbital structure. Consideration of IgG4-RD and accurate diagnosis by biopsy have important implications for prognosis and treatment following the distinction of this condition from the Sjögren syndrome (SjS), granulomatosis with polyangiitis (GPA, formerly Wegener's), sarcoidosis, lymphoma, infection, and other disorders. Rituximab holds promise as an effective steroid-sparing agent or therapy for steroid-resistant cases.

Diffusivity of intraorbital lymphoma vs. IgG4-related DISEASE: 3D turbo field echo with diffusion-sensitised driven-equilibrium preparation technique

OBJECTIVES

3D turbo field echo with diffusion-sensitised driven-equilibrium preparation (DSDE-TFE) is a novel non-echo planar technique for diffusion-weighted (DW) imaging. The purpose of this study was to differentiate intraorbital lymphoma from immunoglobulin G4-related disease (IgG4-RD) using the apparent diffusion coefficient (ADC) derived from DSDE-TFE.

METHODS

Fifteen patients with lymphomas and 8 with IgG4-RDs underwent imaging. ADC and signal intensities compared with normal grey matter on T1-weighted images, fat-suppressed T2-weighted images and fat-suppressed postcontrast T1-weighted images were measured. Statistical analyses were performed using the Mann-Whitney U test and receiver operating characteristic (ROC) analysis.

RESULTS

Intraorbital lesions were clearly visualised on DSDE-TFE without obvious geometrical distortion. The ADC of lymphoma (1.25 ± 0.50 × 10(-3) mm(2)/s; mean ± standard deviation) was significantly lower than that of IgG4-RD (1.67 ± 0.84 × 10(-3) mm(2)/s; P < 0.05). Conventional sequences could not separate lymphoma from IgG4-RD (0.93 ± 0.18 vs. 0.94 ± 0.21 on T1-weighted images, 0.92 ± 0.17 vs. 0.95 ± 0.14 on T2-weighted images and 2.03 ± 0.35 vs. 2.30 ± 0.58 on postcontrast T1-weighted images, for lymphoma and IgG4-RD, respectively; P > 0.05). ROC analysis showed the best diagnostic performance with ADC.

CONCLUSION

The apparent diffusion coefficient derived from diffusion-sensitised driven-equilibrium preparation techniques may help to differentiate lymphoma from immunoglobulin G4-related disease.

KEY POINTS

• Distinguishing between orbital lymphoma and immunoglobulin G4-related disease can be difficult • Intraorbital lesions were clearly visualised on diffusion-sensitised driven-equilibrium preparation magnetic resonance techniques. • Variations in field homogeneity do not affect DSDE-TFE techniques all that much. • ADCs derived from DSDE-TFE may help differentiate lymphoma from IgG4-RD.

Clinical evaluation of international consensus diagnostic criteria for type 1 autoimmune pancreatitis in comparison with Japanese diagnostic criteria 2011

OBJECTIVES

The objective of this study was to evaluate the International Consensus Diagnostic Criteria (ICDC) for type 1 autoimmune pancreatitis (AIP) in comparison with the Japanese criteria 2011 (JPS2011).

METHODS

We retrospectively investigated the usefulness of ICDC in comparison with JPS2011 in 64 patients with AIP and 90 patients with pancreatic cancer.

RESULTS

The sensitivity and specificity of ICDC for AIP were 98.4% (63/64) and 100% (90/90), respectively. The sensitivities and specificities of ductal imaging, serology, other organ involvement, and pancreatic histology were 74.1%, 89.1%, 53.1%, and 26.1% and 94.7%, 94.5%, 100%, and 100%, respectively. On the other hand, the sensitivities and specificities of JPS2011 for AIP were 84.4% (54/64) and 100% (90/90), respectively. The condition of all the 10 patients who were deniable or possible under the JPS2011 could be diagnosed as definitive AIP under the ICDC. The sensitivities and specificities of Japanese criteria 2006, Asian Diagnostic Criteria, and HISORt criteria were 80.6%, 84.4%, and 92.2% and 95.8%, 87.8%, and 100%, respectively.

CONCLUSIONS

The sensitivity and specificity of ICDC are higher than those of previous criteria. The JPS2011 is easy to handle for general practice, and specificity is very high. However, the sensitivity of JPS2011 is lower than that of ICDC, and improvement of sensitivity is to be hoped in the future.

Primary Sjögren's syndrome with chronic tubulointerstitial nephritis and lymphadenopathy mimicking IgG4-related disease

We describe a 62-year-old woman with Sjögren's syndrome (SS) presenting with tubulointerstitial nephritis (TIN) and lymphadenopathy mimicking IgG4-related disease (IgG4-RD). Computed tomography revealed multiple swollen lymph nodes. Biopsy of the largest lymph node showed reactive lymphadenopathy with dense IgG4 positive plasma cell (IgG4 + PC) infiltration. Renal biopsy showed chronic plasma cell-rich TIN with IgG4 + PC infiltration. This case suggests that Immunoglobulin G4 immunostaining does not always support the diagnosis of IgG4-RD in the differential diagnosis between SS and IgG4-RD.

Raised numbers of IgG4-positive plasma cells are a common histopathological finding in orbital xanthogranulomatous disease

PURPOSE

To determine the relation of orbital xanthogranuloma with IgG4-related disease.

METHODS

Retrospective consecutive case series over a period of 25 years. We searched our charts for histologically confirmed orbital xanthogranuloma. Patient files were reviewed for clinical and follow up data including presence or absence of systemic non-ophthalmic manifestations of IgG4 related disease. Slides were re-examined and histopathological classification was re-assessed. Sixteen cases of orbital xanthogranuloma were evaluated. Immunohistochemical stains for IgG and IgG4 were performed. Positive immunohistochemical staining required increased IgG4-positive plasma cells in the involved tissues scored as >50 per high-power field, with IgG4/IgG ratio >0.40.

RESULTS

According to the criteria described above 8/16 (50%) cases showed increased numbers of IgG4-positive plasma cells in the specimens. Two of these patients may have had signs of systemic disease.

CONCLUSION

Raised numbers of IgG4-positive plasma cells are a common finding in histopathological specimens of xanthogranulomatous disease of the orbit and are often not indicative for IgG4 related systemic disease.

IgG4-related kidney disease

IgG4-related kidney disease (IgG4-RKD) is a comprehensive term for renal lesions associated with IgG4-related disease, which is a recently recognized clinical entity characterized by a dense lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells with fibrosis affecting several organs. Tubulointerstitial nephritis with increased IgG4-positive plasma cells and fibrosis is the most dominant feature of IgG4-RKD and may cause acute or chronic renal dysfunction, although some glomerular lesions such as membranous nephropathy are sometimes evident. Radiologically, several characteristic abnormalities are often demonstrated, sometimes mimicking malignancies. IgG4-RKD predominantly affects middle-aged to elderly men, and most patients have accompanying IgG4-related extrarenal lesions such as sialadenitis, lymphadenopathy, or type 1 autoimmune pancreatitis. Serology usually demonstrates high levels of serum total IgG and IgG4, and high levels of serum IgE and hypocomplementemia are also frequent features. Corticosteroid therapy is usually quite effective, leading to amelioration of the renal dysfunction and radiological and serological abnormalities. However, as any delay in treatment may result in irreversible renal failure, early diagnosis and appropriate therapy are very important. Despite these distinctive clinicopathological features of IgG4-RKD, its pathogenesis remains poorly understood. Awareness of this condition and accumulation of more cases worldwide are necessary.

A clinicopathologic case study of two patients with pediatric orbital IgG4-related disease

The purpose of this report is to describe the clinical, radiographica, and histopathologic findings in two pediatric patients with orbital IgG4-related disease.

IgG4-related disease

The term "IgG4-related disease" encompasses several disorders described many years ago under various designations depending on the organ or system involved (e.g., Mikulicz syndrome, Riedel's thyroiditis, and retroperitoneal fibrosis). The clinical presentation varies widely, as one or more organs may be affected, usually in the same region of the body and either synchronously or metachronously. The main targets are the pancreas, bile ducts, salivary glands, lachrymal glands, mediastinal lymph nodes, and retroperitoneum. IgG4-related disease is rare, with an estimated incidence of 0.2 to 1/100,000 in Japan and no available incidence data in occidental countries. Men older than 50 years are predominantly affected. Serum IgG4 levels are often greater than 1.35 g/L. Enlargement of the involved organs, which may be pseudotumoral, is due to a combination of infiltration by T cells and IgG4-expressing plasma cells, storiform fibrosis, and obliterative thrombophlebitis. Glucocorticoid therapy is effective but may be followed by relapses requiring the use of immunomodulating agents such as azathioprine, methotrexate and, more recently, rituximab. IgG4-related disease is not an autoimmune condition related to IgG4 autoantibodies, and neither does it involve immune complexes. Specific joint involvement has been reported in a very small number of patients.

Establishment of a serum IgG4 cut-off value for the differential diagnosis of IgG4-related sclerosing cholangitis: a Japanese cohort

BACKGROUND AND AIM

IgG4-related sclerosing cholangitis (IgG4-SC) must be precisely distinguished from primary sclerosing cholangitis and cholangiocarcinoma (CC) because the treatments are completely different. However, the pathological diagnosis of IgG4-SC is difficult. Therefore, highly specific non-invasive criteria such as serum IgG4 should be established. This study established a cut-off for serum IgG4 to differentiate IgG4-SC from respective controls using serum IgG4 levels measured in Japanese centers.

METHODS

A total of 344 IgG4-SC patients were enrolled in this study. As controls, 245, 110, and 149 patients with pancreatic cancer, primary sclerosing cholangitis, and CC, respectively, were enrolled. IgG4-SC patients were classified into three groups: type 1 (stenosis only in the lower part of the common bile duct), type 2 (stenosis diffusely distributed throughout the intrahepatic and extrahepatic bile ducts), and types 3 and 4 (stenosis in the hilar hepatic region) with 246, 56, and 42 patients, respectively. Serum IgG4 levels were compared, and the cut-offs were established.

RESULTS

The cut-off obtained from receiver operator characteristic curves showed similar sensitivity and specificity to that of 135 mg/dL when all IgG4-SC and controls were compared. However, a new cut-off value was established when subgroups of IgG4-SC and controls were compared. A cut-off of 182 mg/dL can increase the specificity to 96.6% (4.7% increase) for distinguishing types 3 and 4 IgG4-SC from CC. A cut-off of 207 mg/dL might be useful for completely distinguishing types 3 and 4 IgG4-SC from all CC.

CONCLUSIONS

Serum IgG4 is useful for the differential diagnosis of IgG4-SC and controls.

IgG4-related lung disease showing high standardized uptake values on FDG-PET: report of two cases

Immunoglobulin G4 (IgG4)-related lung disease is a disease in which IgG4-positive plasma cells and lymphocytes infiltrate lung tissues along with immunohistochemically evident fibrous interstitial proliferation in the background, in addition to hyper-IgG4 disease. The diagnosis of this disease can be difficult. Here, we report 2 cases with IgG4-related lung disease that was difficult to differentiate from malignant tumors because both cases had pulmonary lesions showing high standardized uptake values (SUV) on positron emission tomography (PET). Case 1: A 75-year-old man under treatment for autoimmune pancreatitis and diabetes mellitus was noted to have multiple nodular opacities in both lungs and a mass density in the right paravertebral region on computed tomography (CT). As high SUVmax was noted for both lesions on exploration by fluorodeoxyglucose (FDG)-PET/CT, an advanced malignant tumor was diagnosed and a video-assisted thoracoscopic (VATS) biopsy was performed and diagnosed IgG4-related lung disease. Case 2: A 48-year-old woman consulted our clinic with a chief complaint of bloody sputum. Chest CT revealed a mass density with 12-, 13-, and 16-mm spiculations in the S2 segment of the right upper lobe and irregular thickening of the pleura including the paravertebral region. The lesion was a mass showing high SUV in the S2 segment on FDG-PET. Malignancy was suspected from the imaging findings, and a VATS biopsy was performed and diagnosed IgG4-related lung disease. Actively undertaking VATS biopsy in cases with this disease is valuable for making the differential diagnosis between malignant tumors and IgG4-related lung disease, since the diagnosis can be difficult in some patients showing high SUV.

The clinical course of patients with IgG4-related kidney disease

Long-term follow-up for IgG4-related kidney disease, including relapse information, is sparse. To gather data on this we retrospectively examined the clinical course of 43 patients with IgG4-related kidney disease, in which most patients were treated with, and maintained on, corticosteroids. One month after the start of treatment, most of the abnormal serology and radiology parameters had improved. In 34 of the steroid-treated patients whose follow-up period was more than 12 months (median 34 months), excluding one hemodialysis patient, the estimated glomerular filtration rate (eGFR) before treatment was over 60 ml/min in 14 patients (group A) and under 60 ml/min in 20 patients (group B). In group A, there was no difference between the eGFR before therapy and at the last review. In group B, the mean eGFR before treatment (34.1 ml/min) was significantly improved after 1 month (45.0 ml/min), and renal function was maintained at a similar level through last follow-up. Among 24 evaluated patients at the last review, however, renal atrophy had developed in 2 of 9 in group A and in 9 of 15 in group B. Relapse of IgG4-related lesions occurred in 8 of 40 treated patients. Thus, the response of IgG4-related kidney disease to corticosteroids is rapid, not total, and the recovery of renal function persists for a relatively long time under low-dose maintenance. A large-scale prospective study to formulate more useful treatment strategies is necessary.

Membranous nephropathy associated with type 1 autoimmune pancreatitis and dominant glomerular IgG4 deposit

We report a case of membranous nephropathy associated with type 1 autoimmune pancreatitis. A 58-year-old man presented with anorexia. Work-up revealed a mass in the pancreatic head, which was subsequently resected. Pathological examination showed diffuse infiltration of immunoglobulin (Ig) G4-positive plasma cells, which was compatible with the diagnosis of type 1 autoimmune pancreatitis. Serum IgG4 was elevated. He developed nephrotic syndrome around the time of the surgery. Kidney biopsy confirmed the diagnosis of membranous nephropathy. Immunofluorescent staining showed predominant glomerular IgG4 deposit among IgG subclasses. Tubulointerstitial nephritis, which is usually a dominant feature of renal involvement in IgG4-related disease, was not observed. The patient was treated with prednisolone and several immunosuppressants. During the course, the degree of proteinuria was associated with the serum IgG4 level. Serum antibody against phospholipase A2 receptor was negative. These findings together with IgG4-dominant glomerular deposit suggest that IgG4 may play a unique role in the pathogenesis of secondary membranous nephropathy caused by IgG4-related diseases.

A subset of Rosai-Dorfman disease exhibits features of IgG4-related disease

In this study we investigated the distribution of IgG4+ plasma cells and regulatory T (T(REG)) cells, a major regulator of IgG4 production, in nodal and extranodal Rosai-Dorfman disease (RDD). Twenty-six specimens (15 nodal, 11 extranodal) were examined, with reactive lymph nodes and site-matched extranodal specimens as controls. Overall, 84.6% (22/26) of the specimens showed various degrees of sclerosis (7 mild, 8 moderate, and 7 severe). Nineteen cases (73.1%) exhibited more than 10 IgG4+ cells/0.060 mm(2) (photographed area at ×40), and 8 cases (30.8%) showed more than 40% of IgG+ cells being IgG4+. Only 1 control case exhibited more than 10 IgG4+ cells/0.060 mm(2) (P < .05). The number of T(REG) cells was comparable between nodal RDD and controls, whereas extranodal RDD exhibited significantly higher numbers of T(REG) cells than controls. These findings demonstrate that a subset of RDD shows features of IgG4-related disease and indicate an overlap between certain aspects of the 2 diseases.