A case of IgG4-related disease with features of Mikulicz’s disease, and retroperitoneal fibrosis and lymphadenopathy mimicking Castleman’s disease

High serum IgA levels in patients with IgG4-related disease are associated with mild inflammation, sufficient disease-specific features, and favourable responses to treatments

OBJECTIVES

Although elevated serum immunoglobulin A (IgA) levels are thought to exclude a diagnosis of IgG4-related disease (IgG4-RD), IgG4-RD has been definitively diagnosed in some patients despite elevated serum IgA levels. This study aimed to clarify the prevalence of elevated IgA levels in patients with IgG4-RD and to compare the clinical features of IgG4-RD patients with and without elevated IgA levels.

METHODS

The clinical features of 169 IgG4-RD patients were retrospectively compared among those with and without elevated serum IgA levels.

RESULTS

Of the 169 patients with IgG4-RD, 17 (10.1%) had elevated serum IgA levels. Those with elevated serum IgA levels showed higher serum C-reactive protein levels and lower prevalence of relapse than those without. Other clinical features did not differ significantly, including inclusion scores of the American College of Rheumatology/European League Against Rheumatism classification criteria. Cox regression analysis showed that elevated serum IgA levels were associated with a lower incidence of relapse. Moreover, patients with elevated serum IgA levels showed prompt improvement in response to glucocorticoids in the IgG4-RD responder index.

CONCLUSIONS

Some patients diagnosed with IgG4-RD have high serum IgA levels. These patients may form a subgroup, characterized by good response to glucocorticoids, less frequent relapse, mildly elevated serum C-reactive protein levels, and possible complications of autoimmune diseases.

Imbalance of Th1 and Th2 Cytokines and Stem Cell Therapy in Pathological Pain

The pathophysiological importance of T helper 1 (Th1) and Th2 cell cytokines in pathological pain has been highly debated in recent decades. However, the analgesic strategy targeting individual cytokines still has a long way to go for clinical application. In this review, we focus on the contributions of Th1 cytokines (TNF-α, IFN-γ, and IL-2) and Th2 cytokines (IL-4, IL-5, IL-10, and IL-13) in rodent pain models and human pain-related diseases. A large number of studies have shown that Th1 and Th2 cytokines have opposing effects on pain modulation. The imbalance of Th1 and Th2 cytokines might determine the final effect of pain generation or inhibition. However, increasing evidence indicates that targeting the individual cytokine is not sufficient for the treatment of pathological pain. It is practical to suggest a promising therapeutic strategy against the combined effects of Th1 and Th2 cytokines. We summarize the current advances in stem cell therapy for pain-related diseases. Preclinical and clinical studies show that stem cells inhibit proinflammatory cytokines and release enormous Th2 cytokines that exhibit a strong analgesic effect. Therefore, a shift of the imbalance of Th1 and Th2 cytokines induced by stem cells will provide a novel therapeutic strategy against intractable pain. It is extremely important to reveal the cellular and molecular mechanisms of stem cell-mediated analgesia. The efficiency and safety of stem cell therapy should be carefully evaluated in animal models and patients with pathological pain.

IgG4-related disease and idiopathic multicentric Castleman's disease: confusable immune-mediated disorders

IgG4-related disease (IgG4-RD) and idiopathic multicentric Castleman's disease (iMCD) are both rare systemic immune-mediated disorders. However, pathogenesis differs markedly between the two diseases, and differing therapeutic strategies are adopted: IgG4-RD is treated using a moderate dose of glucocorticoids or rituximab, while iMCD therapy involves an interleukin (IL)-6 targeted approach. Nonetheless, some clinical features of IgG4-RD and iMCD overlap, so differential diagnosis is sometimes difficult, even though the classification and diagnostic criteria of the diseases require careful exclusion of the other. The key findings in IgG4-RD are high IgG4/IgG ratio, allergic features, and germinal centre expansion involving T follicular helper cells, while iMCD involves polyclonal antibody production (high IgA and IgM levels), sheet-like mature plasma cell proliferation, and inflammatory features driven by IL-6. The distribution of organ involvement also provides important clues in both diseases. Particular attention should be given to differential diagnosis using combined clinical and/or pathological findings, because single features cannot distinguish IgG4-RD from iMCD. In the present review, we discuss the similarities and differences between IgG4-RD and iMCD, as well as how to distinguish the two diseases.

Idiopathic multicentric Castleman disease presenting progressive reticular honeycomb infiltration of lung and immunoglobulin G and immunoglobulin G4 dominant hypergammaglobulinemia

Multicentric Castleman disease (MCD) is an uncommon systemic lymphoproliferative disorder that may cause multiple organ damage. Castleman disease-associated diffuse parenchymal lung disease (DPLD) has not been well studied. A 32-year-old man was referred to our hospital for progressive generalized weakness, light-headedness, and dyspnea on exertion for more than one year. Laboratory evaluations showed profound anemia, an elevated erythrocyte sedimentation rate, and an increased C-reactive protein level with polyclonal hypergammaglobulinemia. Chest radiography, computed tomography (CT), and positron emission tomography-CT scan demonstrated diffuse lung infiltration with multiple cystic lesions and multiple lymphadenopathy. In addition to these clinical laboratory findings, bone marrow, lung, and lymph node biopsies confirmed the diagnosis of idiopathic MCD (iMCD). Siltuximab, an interleukin-6 inhibitor, and glucocorticoid therapy were initiated. The patient has been tolerating the treatment well and had no disease progression or any complications in 4 years. Herein, we report this case of human herpesvirus-8-negative iMCD-associated DPLD accompanied by multiple cystic lesions, multiple lymphadenopathy, and polyclonal hypergammaglobulinemia with elevated immunoglobulin G (IgG) and IgG4 levels. We recommend a close evaluation of MCD in cases of DPLD with hypergammaglobulinemia.

Imaging of IgG4-Related Disease in the Head and Neck: A Systematic Review, Case Series, and Pathophysiology Update

This systematic review aims to clarify and comprehensively detail the sometimes variable published imaging features as well as the pathogenesis, clinical diagnostic criteria, and treatment options of IgG4-Related Diseases (IgG4-RD) in the head and neck to aid the radiologist in diagnosing relapse and new sites of disease. A literature search in PubMed and EMBASE for reported cases of IgG4-RD was performed in December 2019. Case reports or series of IgG4-RD in the head and neck in adults that included sufficient imaging and pathology findings were included. This yielded 50 reports. IgG4-RD locations included the orbits, thyroid, pituitary gland, paranasal sinuses, salivary and parotid glands, larynx, pharynx, cervical lymph nodes, meninges, and skull base. Most lesions demonstrated non-specific homogenous CT attenuation, diffuse enhancement, isointense/low T2 signal intensity, and low T1 signal intensity. 6 cases from our institution followed previously reported imaging patterns.

Distinct features distinguishing IgG4-related disease from multicentric Castleman's disease

Objectives

Differentiating IgG4-related disease (IgG4-RD) from multicentric Castleman’s disease (MCD) is challenging because both diseases present high serum IgG4. The objective of this study is to clarify the differences in characteristics and identify a clinically useful approach to differentiate these two diseases.

Methods

Forty-five consecutive patients with untreated active IgG4-RD and 33 patients with MCD were included in this study, who visited our institution from January 2000 to August 2016. The clinical and laboratory findings for the patients of the two diseases were compared. Various combinations of the distinctive findings were evaluated to identify the most efficient differentiating features between IgG4-RD and MCD.

Results

The levels of serum IgG4 were not different between the two diseases. Orbits, lacrimal glands, salivary glands or pancreas were involved in 88.9% of IgG4-RD cases and only in 3.0% of MCD cases. All MCD cases involved lymph nodes. Atopic history was characteristic for IgG4-RD. The levels of C reactive protein (CRP) with a cut-off of 0.80 mg/dL and IgA with a cut-off of 330 mg/dL were the most distinctive. The combination of ‘Orbits, lacrimal glands, salivary glands or pancreas involvement, atopic history, or non-involvement of lymph node’ and ‘CRP ≤ 0.8 mg/dL or IgA ≤ 330 mg/dL’ yielded the probability of 97.8% in IgG4-RD, while that of 3.0 % in patients with MCD.

Conclusions

Our study revealed distinct features between IgG4-RD and MCD. Differentiating between the diseases based on those distinct features, including distribution of organ involvement, atopic history, levels of IgA and CRP, was a useful approach.

Immunoglobulin G4-Related Lymphadenopathy

Immunoglobulin G4-related lymphadenopathy (IgG4-RLAD) occurs in the setting of extranodal IgG4-related disease (IgG4-RD), an immune-mediated process described in many organ systems characterized by lymphoplasmacytic infiltrates with abundant IgG4-positive plasma cells and fibrosis. Although the morphologic features in the lymph node sometimes resemble those seen at the extranodal sites, 5 microscopic patterns have been described, most of which resemble reactive lymphoid hyperplasia. This morphologic variability leads to unique diagnostic challenges and a broad differential diagnosis. As IgG4-RD may be exquisitely responsive to steroids or other immunotherapy, histologic recognition and inclusion of IgG4-RLAD in the differential diagnosis is vital.

Enhanced IgG4 production by follicular helper 2 T cells and the involvement of follicular helper 1 T cells in the pathogenesis of IgG4-related disease

Background

The aim of this study was to elucidate the function of circulating follicular helper T (Tfh) cell subsets in helping B cells in patients with active, untreated IgG4-related disease (IgG4-RD) and determine their relationship with disease activity.

Methods

Seventeen consecutive patients with active, untreated IgG4-RD, 20 with primary Sjögren syndrome (pSS), 5 with multicentric Castleman’s disease (MCD), and 12 healthy controls (HC) were enrolled. Tfh cell subset function was evaluated by co-culture with naïve B cells in vitro. Activated Tfh cell subsets were defined as a CCR7^lowPD-1^high subset among Tfh cell subsets. Disease activity was evaluated by IgG4-RD responder index (IgG4-RD RI) score.

Results

The number of Tfh2 cells was significantly higher in IgG4-RD compared to pSS, MCD, or HC, and correlated with serum IgG4 level or the number of plasmablasts. In vitro, Tfh2 cells more efficiently induced the differentiation of naïve B cells into plasmablasts compared to Tfh1 or Tfh17 cells. Of note, while IgG production in culture supernatants of Tfh2 cells was comparable between IgG4-RD and HC, IgG4 production was significantly higher with Tfh2 cells from patients with IgG4-RD than in those from HC. Accordingly, the IgG4:IgG ratio in culture supernatants was also significantly higher with Tfh2 cells from IgG4-RD compared to HC. Moreover, the number of activated Tfh2 cells was higher in IgG4-RD compared to pSS, MCD, or HC, and strongly correlated with IgG4-RD RI score in the baseline active phase. Particularly, the number of activated Tfh2 cells was associated with the number of affected organs and serum IgG4 level. Importantly, the number of activated Tfh2 cells was decreased after glucocorticoid treatment and paralleled disease improvement. Moreover, the number of activated Tfh1 cells was also increased in IgG4-RD compared to pSS, MCD, or HC, correlating with IgG4-RD RI score, but not with serum IgG4 level.

Conclusions

Tfh2 cells, but not Tfh1 or Tfh17 cells, induce the differentiation of naïve B cells into plasmablasts and enhanced production of IgG4 in patients with active, untreated IgG4-RD. Furthermore, activated Tfh2 cells reflect disease activity, suggesting the involvement of this T cell subset in the pathogenesis of IgG4-RD. Interestingly, the number of activated Tfh1 cells was also increased in IgG4-RD, correlating with disease activity but not with serum IgG4 level, suggesting the involvement of Tfh1 cells but not in the process of IgG4 production in patients with IgG4-RD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1064-4) contains supplementary material, which is available to authorized users.

IgG4-related Disease Involving Multiple Organs with Elevated Serum Interleukin-6 Levels

A 63-year-old woman presented to our hospital with elevated levels of serum IgG4, marked wall thickening of the gallbladder, hepatomegaly, and abdominal lymphadenopathy. She experienced a recurrent fever and leg edema. Her laboratory data demonstrated anemia, hypoalbuminemia, and elevated serum levels of interleukin-6 and C-reactive protein. The patient was eventually diagnosed with IgG4-related disease according to the comprehensive diagnostic criteria, although the patient exhibited common clinical manifestations of multicentric Castleman disease such as a fever, anemia, lymphadenopathy, and elevated levels of serum interleukin-6 and C-reactive protein. This case report highlights the difficulties in differentiating between these two diseases.

Multicentric Castleman disease mimicking IgG4-related disease: A case report

A 50-year-old woman was referred to our hospital for shoulder joint stiffness. She had a history of polyclonal hypergammaglobulinemia and an elevated C-reactive protein level. Her laboratory data revealed an elevated serum immunoglobulin G4 (IgG4) level, hypergammaglobulinemia, and rheumatoid factor positivity in the absence of anticyclic citrullinated peptide antibody. [18^F]-Fluorodeoxyglucose positron emission tomography showed significant [18^F]-fluorodeoxyglucose uptake in multiple lymph nodes (axillary, hilar, para-aortic, and inguinal). Biopsy of the inguinal lymph node showed expansion of the interfollicular areas by heavily infiltrating plasma cells, consistent with multicentric Castleman disease (MCD). Immunohistochemical analysis revealed a 37.3% IgG4-positive:IgG-positive plasma cell ratio, indicating overlapping IgG4-related disease. However, serological cytokine analysis revealed elevated levels of interleukin-6 (9.3 pg/ml) and vascular endothelial growth factor (VEGF) (1210 pg/ml), which are compatible with MCD. Corticosteroid treatment resolved the serological and imaging abnormalities. IgG4-related disease can mimic MCD, and it is crucial to distinguish between these two diseases. Serum interleukin-6 and VEGF levels may help to discriminate MCD from IgG4-related disease.

Rethinking Ormond's disease: "idiopathic" retroperitoneal fibrosis in the era of IgG4-related disease

Idiopathic retroperitoneal fibrosis (RPF) is a periaortic sclerotic disease that encases adjacent retroperitoneal structures, particularly the ureters. A subset of idiopathic RPF cases can be associated with IgG4-related disease, but the frequency of this association is not clear. We selected 23 cases of idiopathic RPF and identified IgG4-related RPF cases based on the presence of IgG4+ plasma cells in the tissue, using an IgG4/IgG ratio cutoff of >40%. We then compared the IgG4-related RPF patients and the non-IgG4-related RPF patients in terms of both the presence of histopathologic features typical of IgG4-related disease and the simultaneous occurrence (or history) of other organ manifestations typical of IgG4-related disease. The IgG4-related RPF and non-IgG4-related RPF groups were also analyzed in terms of clinical, laboratory, and radiologic features and treatment review. We identified 13 cases of IgG4-related RPF (57% of the total cohort). The distinguishing features of IgG4-related RPF were histopathologic and extra-organ manifestations of IgG4-related disease. The IgG4-related RPF patients were statistically more likely than non-IgG4-related RPF patients to have retroperitoneal biopsies showing lymphoplasmacytic infiltrate (p = 0.006), storiform fibrosis (p = 0.006), or tissue eosinophilia (p = 0.0002). Demographics of the 2 groups, including a middle-aged, male predominance (mean age, 58 yr; 73% male), were similar. IgG4-related disease accounts for a substantial percentage of patients with "idiopathic" RPF. Histopathologic features such as storiform fibrosis, obliterative phlebitis, and tissue eosinophilia are critical to identifying this disease association. Extraretroperitoneal manifestations of IgG4-related disease are also often present among patients with IgG4-related RPF. Elevated IgG4/total IgG ratios in tissue biopsies are more useful than the number of IgG4+ plasma cells per high-power field in cases of RPF that are highly fibrotic.