Polyclonal hypergammaglobulinaemia: assessment, clinical interpretation, and management

Rosai-Dorfman-Destombes disease in adults: a single center experience

Recent advances in Rosai-Dorfman-Destombes disease (RDD), notably molecular testing, targeted therapy, and PET-CT imaging, hold promise for better recognition and improved outcomes. This study presents patients diagnosed and treated in a "real world" setting, where navigating limited resources must be considered. This retrospective single-center review includes 15 adult patients diagnosed with RDD at Vancouver General Hospital between November 2015 and October 2023. The cohort comprised five males and ten females with a median age 53 years (range 19-80 years). All 15 patients had extra-nodal disease; 11 patients exclusively had extra-nodal disease, and four patients also had lymph node involvement. Seven patients had tissue next-generation sequencing, identifying MAP2K1 mutations in four cases and a KRAS p.K117N mutation in one case that was treated with targeted therapy using trametinib. PET-CT was used for disease staging in four cases. Six patients with refractory disease tolerated lenalidomide and dexamethasone without significant toxicity; three patients achieved complete response, and three had partial response. This study highlights RDD's diverse extra-nodal manifestations. Lenalidomide combined with dexamethasone is an effective and well-tolerated treatment option for select patients, especially those with refractory disease. Broad utilization of NGS and PET-CT can positively influence management decisions.

Unusual Cases of Monoclonal Gammopathy of Renal Significance

Introduction

Monoclonal gammopathy of renal significance (MGRS) is a rare entity describing patients with renal impairment related to the secretion of immunoglobulins without hematological criteria for treatment of a specific disease. We present 3 cases of MGRS identified at our center that were either rare or difficult to diagnose. Case Presentations. The first patient presented with monoclonal membranoproliferative glomerulonephritis in the context of known chronic lymphocytic leukemia (CLL), diagnosed about 10 years prior. She presented with nephritic syndrome with serum protein electrophoresis revealing an IgG/lambda peak of less than 1 g/L, stable from the last few years. A renal biopsy confirmed a diagnosis of monoclonal membranoproliferative glomerulonephritis with granular IgG and C3 deposits of various sizes. The second patient presented with renal TMA in the context of IgM MGUS. The patient was admitted for acute nephritic syndrome and thrombotic microangiopathy. Serum protein electrophoresis demonstrated IgM/kappa paraprotein at 1.8 g/L, with a kappa/lambda ratio of 5.48. Renal biopsy demonstrated endocapillary proliferative glomerulonephritis associated with the presence of numerous monotypic IgM/kappa intracapillary pseudothrombi. Characteristic changes of thrombotic microangiopathy were also described. The third patient presented with immunotactoid glomerulonephritis likely from small B-cell lymphoma that later transformed to DLBCL. The patient presented with acute renal failure with IgM/kappa paraprotein of less than 1 g/L on electrophoresis and with a kappa/lambda ratio of 7.09. A diagnosis of immunotactoid glomerulonephritis was made on renal biopsy. Bone marrow with limited specimen revealed a B-cell infiltrate. Biopsy of a breast lesion was compatible with diffuse large B-cell lymphoma (DLBCL). Lymphomatous cells expressed IgM/kappa, thus confirming paraprotein-associated renal lesion.

Conclusion

We described 3 different cases of MGRS, highlighting the diversity of renal pathohistological presentations and different associated lymphoproliferative disorders. Biopsy should rapidly be considered, as early diagnosis of MGRS is essential to initiate clone-directed therapy promptly to prevent progression to ESRD or hematologic progression to malignancy.

A hypothesis on treatment strategy of severe multicentric Castleman disease with continuous renal replacement therapy

Castleman disease (CD) is a rare lymphoproliferative disorder, with non-specific clinical manifestations, often delayed diagnosis and treatment, which pose a significant challenge in the present times. Patients diagnosed with this disease have poor prognosis due to the limited treatment options. Multicentric CD occurs at multiple lymph node stations and is associated with a proinflammatory response that leads to the development of the so-called 'B symptoms'. IL-6 seems to be a key cytokine involved in various manifestations such as lymphadenopathies, hepatosplenomegaly, and polyclonal hypergammaglobulinemia. Its levels correlate with the activity of the disease. Other consequences of MCD include increased fibrinogen levels leading to deep vein thrombosis and thromboembolic disorders, high hepcidin levels causing anaemia, elevated VEGF levels promoting angiogenesis and vascular permeability, which, along with hypoalbuminemia, induce oedema, ascites, pleural and pericardial effusions, and in severe cases, generalized anasarca. In extreme cases multiple organ failure can occur, often resulting in death. We propose the use of continuous renal replacement therapy (CRRT) in managing severe multicentric CD. Our arguments are based on the principles that CRRT is able to remove IL-6 from circulation thus attenuating the cytokine storm, can influence hepcidin levels, and reduction in oedema, and is often used in multiple organ failure to regain homeostasis control. Therefore, it could be used as a therapy or bridge therapy in severe cases. To sustain our hypothesis with evidence, we have gathered several studies from the literature confirming the successful removal of cytokines, especially IL-6 from circulation, which can be used as a starting point.

Idiopathic multicentric Castleman disease with marrow fibrosis and extramedullary hematopoiesis

BACKGROUND

Idiopathic multicentric Castleman disease (iMCD) is a rare inflammatory disorder mediated by excessive proinflammatory cytokine signaling, most notably by interleukin 6 (IL-6). IL-6-induced extramedullary hematopoiesis (EMH) has been reported in murine models of iMCD. Herein we present four cases of iMCD with EMH in humans.

CASE SERIES

The index case is a 24-year-old white woman who presented with pancytopenia, hepatosplenomegaly, and diffuse lymphadenopathy (LAD) with EMH in core lymph node biopsies. We then searched ACCELERATE, a Castleman disease (CD) natural history registry, and identified three additional CD cases with EMH reported in biopsies: A 23-year-old Asian man with fatigue, edema, LAD, and splenomegaly; a 20-year-old white man with fever, dyspnea, LAD, and hepatosplenomegaly; and a 50-year-old white man with constitutional symptoms, LAD, and myelodysplastic syndrome in bone marrow with a KRAS mutation.

RESULTS

All four patients presented with thrombocytopenia and fever and/or markedly elevated C-reactive protein. Patient 1 had iMCD-NOS (not otherwise specified) with severe thrombocytopenia, reticulin fibrosis in bone marrow, small volume LAD and organomegaly but no anasarca. The other three patients had iMCD-TAFRO (thrombocytopenia, anasarca, reticulin fibrosis, renal dysfunction, organomegaly). Two had mixed CD and two had hypervascular CD in lymph nodes. All four had bone marrow hypercellularity and megakaryocyte hyperplasia and two had reticulin fibrosis.

CONCLUSIONS

This case series demonstrates that EMH can be seen in CD, particularly in iMCD-TAFRO. Given the similarity of this finding to previous murine models of IL-6-induced marrow and lymph node changes we hypothesize that this is an IL-6-mediated phenomenon.

Unveiling the value of C-reactive protein as a severity biomarker and the IL4/IL13 pathway as a therapeutic target in recessive dystrophic epidermolysis bullosa: A multiparametric cross-sectional study

Patients with recessive dystrophic epidermolysis bullosa (RDEB) experience numerous complications, which are exacerbated by inflammatory dysregulation and infection. Understanding the immunological mechanisms is crucial for selecting medications that balance inflammation control and immunocompetence. In this cross-sectional study, aiming to identify potential immunotherapeutic targets and inflammatory biomarkers, we delved into the interrelationship between clinical severity and systemic inflammatory parameters in a representative RDEB cohort. Encompassing 84 patients aged 1-67 and spanning all three Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) severity categories, we analysed the interrelationship of infection history, standard inflammatory markers, systemic cytokines and Ig levels to elucidate their roles in RDEB pathophysiology. Our findings identify C-reactive protein as an excellent biomarker for disease severity in RDEB. A type 2 inflammatory profile prevails among moderate and severe RDEB patients, correlating with dysregulated circulating IgA and IgG. These results underscore the IL4/IL13 pathways as potential evidence-based therapeutic targets. Moreover, the complete inflammatory scenario aligns with Staphylococcus aureus virulence mechanisms. Concurrently, abnormalities in IgG, IgE and IgM levels suggest an immunodeficiency state in a substantial number of the cohort's patients. Our results provide new insights into the interplay of infection and immunological factors in the pathogenesis of RDEB.

The "great imitator": IgG4-related disease of the oral cavity. Two case reports and scoping review

This study aimed to review the lesser-known intraoral manifestations of immunoglobulin G4-related disease (IgG4-RD). In this paper we report an unprecedented case of oral IgG4-RD mimicking angiolymphoid hyperplasia with eosinophilia (ALHE), and another case presenting as plasma cell gingivitis. We then performed a scoping review of published cases of IgG4-RD involving the oral cavity. The following data were collected for each case: age, sex, intraoral site(s) involved, clinical appearance, imaging features, serum IgG4 values, histopathology, treatment, and follow-up duration. Fifty-one cases of oral IgG4-RD were published in literature. The hard palate and jaw bones were the two main locations reported, while the histological identification of a IgG4/IgG plasma cells ratio ≥40% was fundamental for diagnosis. Conversely, the pathological features of storiform fibrosis and obliterative phlebitis were not common. Future reports regarding oral IgG4-RD should report clear adherence to the recognized international diagnostic criteria of the disease.

In adult X-CGD patients, regulatory T cells are expanded while activated T cells display a NOX2-independent ROS increase

The X-linked chronic granulomatous disease (X-CGD), a rare genetic disease characterised by recurrent infections, is caused by mutations of NOX2. Significant proportions of X-CGD patients display signs of immune dysregulation. Regulatory T cells (Tregs) are CD4+T lymphocytes that expand in active inflammation and prevent autoimmune disorders. Here we asked whether X-CGD is associated to Treg dysfunctions in adult patients. To this aim, the frequency of Tregs was analysed through intracellular flow cytometry in a cohort of adult X-CGD patients, carriers and controls. We found that Tregs were significantly expanded and activated in blood of adult X-CGD patients, and this was associated with activation of conventional CD4+T cells (Tconvs). T cell activation was characterised by accumulation of intracellular ROS, not derived from NOX2 but likely produced by cellular metabolism. The higher TNF production by Tconvs in X-CGD patients might contribute to the expansion of Tregs through the TNFR2 receptor. In summary, our data indicate that Tregs expand in adult X-CGD in response to immune activation, and that the increase of NOX2-independent ROS content is a feature of activated T cells.

Comparison of clinical features and outcomes of proliferative, fibrotic, and mixed subtypes of IgG4-related disease: A retrospective cohort study

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized immune-mediated disorder that can affect almost any organ in the human body. IgG4-RD can be categorized into proliferative and fibrotic subtypes based on patients' clinicopathological characteristics. This study aimed to compare the clinical manifestations, laboratory findings, and treatment outcomes of IgG4-RD among different subtypes.

METHODS

We prospectively enrolled 622 patients with newly diagnosed IgG4-RD at Peking Union Medical College Hospital from March 2011 to August 2021. The patients were divided into three groups according to their clinicopathological characteristics: proliferative, fibrotic, and mixed subtypes. We compared demographic features, clinical manifestations, organ involvement, laboratory tests, and treatment agents across three subtypes. We then assessed the differences in treatment outcomes among 448 patients receiving glucocorticoids alone or in combination with immunosuppressants. Moreover, risk factors of relapse were revealed by applying the univariate and multivariate Cox regression analysis.

RESULTS

We classified the 622 patients into three groups consisting of 470 proliferative patients, 55 fibrotic patients, and 97 mixed patients, respectively. We found that gender distribution, age, disease duration, and frequency of allergy history were significantly different among subgroups. In terms of organ involvement, submandibular and lacrimal glands were frequently involved in the proliferative subtype, while retroperitoneum was the most commonly involved site in both fibrotic subtype and mixed subtype. The comparison of laboratory tests revealed that eosinophils ( P = 0.010), total IgE ( P = 0.006), high-sensitivity C-reactive protein ( P <0.001), erythrocyte sedimentation rate ( P <0.001), complement C4 ( P <0.001), IgG ( P = 0.001), IgG1 (P <0.001), IgG4 (P <0.001), and IgA ( P <0.001), at baseline were significantly different among three subtypes. Compared with proliferative and mixed subtypes, the fibrotic subtype showed the lowest rate of relapse (log-rank P = 0.014).

CONCLUSIONS

Our study revealed the differences in demographic characteristics, clinical manifestations, organ involvement, laboratory tests, treatment agents, and outcomes across proliferative, fibrotic, and mixed subtypes in the retrospective cohort study. Given significant differences in relapse-free survival among the three subtypes, treatment regimens, and follow-up frequency should be considered separately according to different subtypes.

Serological characteristics and clinical implications of IgG subclasses in visceral leishmaniasis

OBJECTIVES

Visceral leishmaniasis (VL) represents the most severe form of Leishmaniasis infection, often resulting in fatality without timely treatment. Previous studies have found that immunosuppression increases the risk of VL disease progression and mortality, and the total immunoglobulin G (IgG) levels in peripheral blood vary before and after treatment. However, the distinct levels and roles of IgG subclasses in VL have not been documented yet. This study aims to elucidate the characteristics and clinical significance of IgG subclasses in VL.

METHODS

A total of 43 cases newly-diagnosed with VL were enrolled in the cohort. We measured the levels of IgG subclasses before and after standard treatment and conducted assessments of bone marrow features. In addition, we analysed other haematological indices and examined the variations in IgG subclasses, as well as their correlation with clinical and laboratory factors.

RESULTS

The levels of total IgG, IgG1, and the ratios of both IgG1/IgG and IgG1/IgG2 decreased significantly after treatment, whereas the ratios of IgG2/ IgG showed an obvious increase. The VL patients without hyperglobulinemia displayed significant lower IgG1/IgG2 ratios, but higher IgG2/IgG ratios compared with those with hyperglobulinemia. In addition, VL patients with positive bone marrow amastigotes had significant higher IgG1/IgG and IgG1/IgG2 ratios, but lower IgG2/IgG ratios. IgG subclasses were correlated with abnormal blood test results, particularly immunological elements including IgM and Complement 4 (C4).

CONCLUSIONS

IgG1 and IgG2 exhibited contrasting changes after treatment in VL patients. The features of bone marrow and laboratory tests indicated that IgG1 and IgG2 serve different roles in the progression of VL. The ratios of IgG subclasses may be more precise indicators to evaluate immune reaction in VL than traditional total IgG.

Mass spectrometry in IgG4-related disease diagnosis

We compared liquid chromatography tandem mass spectrometry (LC-MS/MS) against Binding Site immunonephelometry (BSIN) with regards to these methods' abilities to diagnose IgG4-related disease (IgG4-RD). IgG subclasses were gathered from laboratory from December 2011 to December 2020. The IgG4-RD positive and negative patients were diagnosed according to the ACR/EULAR classification criteria by extensive chart review. Both methods' results were compared in terms of test characteristics. For BSIN, there were 43 IgG4-RD positive cases and 174 disease negative cases, while for LC-MS/MS, there were 102 IgG4-RD positive cases and 562 disease negative cases. The majority of IgG4-RD patients by BSIN and LC-MS/MS had an elevated IgG4 level, 81% and 86%, respectively. For BSIN, the ROC curve, cut-off value of 1.25 g/L, had a sensitivity of 81% and a specificity of 84%. For LC-MS/MS, the ROC curve, cut-off value of 1.25 g/L, had a sensitivity of 86% and a specificity of 84%. The responder index score to IgG4 level r-correlation value for BSIN and LC-MS/MS was 0.5 and 0.6, respectively. In our center, LC-MS/MS and BSIN are equivalent test methods in IgG4-RD diagnosis. IgG4 level does correlate with disease activity by the responder index. LC-MS/MS is a valid and equally reliable alternative to BSIN in the diagnosis of IgG4-related disease.

Understanding hypergammaglobulinemia in experimental or natural visceral leishmaniasis

Nonspecific hypergammaglobulinemia (HGG) occurs in symptomatic human visceral leishmaniasis (VL) caused by L. L. infantum. This study assessed this finding in experimental infection in hamsters and natural infection in dogs. The serum concentration of proteins, albumin and globulins was determined through the biuret and bromocresol green reaction, where the HGG was better expressed through the albumin/globulin (A/G) ratio. HGG was associated with a higher concentration of specific anti-glycan antibodies (BSA-G)/promastigote soluble extract (PSE) and the presence of circulating immune complexes (IC) by dissociative enzyme-linked immunoassay (ELISA). The study found monovalent IC in 37.9% (PSE) and 50% (BSA-G) of sera from infected hamsters, with increased frequency as the disease progressed. HGG was found in >60% of the samples in dogs with VL, associated with higher levels of specific immunoglobulin (Ig)A and IgM, but not IgG, determined using the PSE and BSA-G ELISA. HGG was associated with the presence of monovalent IC in 58.9% (PSE) and 63.4% (BSA-G) positive dog samples. HGG may result not only from the nonspecific activation of B cells, with greater production of specific and nonspecific antibodies, but also due to lower IgG excretion due to the presence of soluble monovalent IC. HGG correlates to the progression of VL and may be a marker for manifested disease.

Screening for and diagnosis of monoclonal gammopathy

Monoclonal gammopathy is a spectrum of disorders characterised by clonal proliferation of plasma cells or lymphocytes, which produce abnormal immunoglobulin or its components (monoclonal proteins). Monoclonal gammopathies are often categorised as low-tumour-burden diseases (eg, amyloid light chain (AL) amyloidosis), premalignant disorders (such as monoclonal gammopathy of undetermined significance and smouldering multiple myeloma), and malignancies (eg, multiple myeloma and Waldenström's macroglobulinaemia). Such diversity of concentration and structure makes monoclonal protein a challenging clonal marker. This article provides an overview on initial laboratory testing of monoclonal gammopathy to guide clinicians and laboratory professionals in the selection and interpretation of appropriate investigations.

From Infection to Death: An Overview of the Pathogenesis of Visceral Leishmaniasis

Kala-azar, also known as visceral leishmaniasis (VL), is a disease caused by Leishmania infantum and L. donovani. Patients experience symptoms such as fever, weight loss, paleness, and enlarged liver and spleen. The disease also affects immunosuppressed individuals and has an overall mortality rate of up to 10%. This overview explores the literature on the pathogenesis of preclinical and clinical stages, including studies in vitro and in animal models, as well as complications and death. Asymptomatic infection can result in long-lasting immunity. VL develops in a minority of infected individuals when parasites overcome host defenses and multiply in tissues such as the spleen, liver, and bone marrow. Hepatosplenomegaly occurs due to hyperplasia, resulting from parasite proliferation. A systemic inflammation mediated by cytokines develops, triggering acute phase reactants from the liver. These cytokines can reach the brain, causing fever, cachexia and vomiting. Similar to sepsis, disseminated intravascular coagulation (DIC) occurs due to tissue factor overexpression. Anemia, hypergammaglobulinemia, and edema result from the acute phase response. A regulatory response and lymphocyte depletion increase the risk of bacterial superinfections, which, combined with DIC, are thought to cause death. Our understanding of VL's pathogenesis is limited, and further research is needed to elucidate the preclinical events and clinical manifestations in humans.

Clinical presentation and organ-based outcomes of Multifocal fibrosclerosis: A systematic review

Objectives

Multifocal fibrosclerosis is a rare disorder causing progressive fibrosis of multiple organ systems. Existing data on the disease show that there are multiple manifestations of the disease, with different outcomes. However, quantitative data are scarce, prompting the need for our investigation.

Method

A comprehensive systematic review was performed from inception to November 16, 2022, with the restriction of English language, not including review articles. Article screening and extraction was performed independently, and shortlisted articles were assessed for bias. Analysis was performed using SPSS Version 25 (IBM® SPSS® Statistics; Chicago, IL, USA). Data were presented as frequencies and percentages, with a confidence interval of 95%.

Result

This review included 134 patients, with 78 (58.2%) males. Mean age was 53.6 years and included two pediatric patients. The most common comorbidity was diabetes (9.7%). Prevalent presenting symptoms included pain (47.8%) and swelling (35.1%). A mean of 2.51 organs or anatomical sites was affected, retroperitoneum (64.2%) being most affected. The pancreas (30.0%) and digestive system (47.0%) were the organs/organ systems most affected. Patients had favorable outcomes in 79.1% of cases, 87.3% had no relapse, and 91.8% of patients survived the condition.

Conclusion

The findings in this study provide a quantitative measurement of the demographics, presentations, organ manifestations, and outcomes of multifocal fibrosclerosis. We found the disease to be prevalent in males in Japan or the United States, with the abdomen and its organs being commonly involved.

A prospective study to identify preoperative serum parameters for spinal implant infection detected by sonication fluid culture

PURPOSE

Low-virulent microorganisms identified on pedicle screws by sonication fluid culture (SFC) are an important cause of implant loosening. While sonication of explanted material improves the detection rate, the risk of contamination exists and no standardized diagnostic criteria for chronic low-grade spinal implant-related infection (CLGSII) are stablished. Besides, the role of serum C-reactive protein (CRP) and procalcitonin (PCT) in CLGSII has not been adequately investigated.

METHODS

Blood samples were collected prior to implant removal. To increase sensitivity, the explanted screws were sonicated and processed separately. Patients exhibiting at least one positive SFC were classified in the infection group (loose criteria). To increase specificity, the strict criteria only considered multiple positive SFC (≥ 3 implants and/or ≥ 50% of explanted devices) as meaningful for CLGSII. Factors which might promote implant infection were also recorded.

RESULTS

Thirty-six patients and 200 screws were included. Among them, 18 (50%) patients had any positive SFCs (loose criteria), whereas 11 (31%) patients fulfilled the strict criteria for CLGSII. Higher serum protein level was the most accurate marker for the preoperative detection of CLGSSI, exhibiting an area under the curve of 0.702 (loose criteria) and 0.819 (strict criteria) for the diagnosis of CLGSII. CRP only exhibited a modest accuracy, whereas PCT was not a reliable biomarker. Patient history (spinal trauma, ICU hospitalization and/or previous wound-related complications) increased the likelihood of CLGSII.

CONCLUSION

Markers of systemic inflammation (serum protein level) and patient history should be employed to stratify preoperative risk of CLGSII and decide the best treatment strategy.

Case report: Importance of early and continuous tocilizumab therapy in nephrotic syndrome associated with idiopathic multicentric Castleman disease: A case series

Idiopathic multicentric Castleman disease (iMCD) is a systemic and polyclonal lymphoproliferative disease involving multiple organs, including the kidneys, due to the overproduction of interleukin-6 (IL-6). Recently, several reports have suggested that excessive IL-6 actions in iMCD could have a causal relationship with the development of diverse histopathological renal manifestations that cause nephrotic syndrome. However, the treatment for such cases remains unclear. We report a series of three cases of nephrotic syndrome due to iMCD that helps to delineate the importance of early and continuous therapy with the anti-interleukin-6 receptor antibody tocilizumab. First, treatment was suspended for infectious control, and the patient presented with nephrotic syndrome due to diffuse mesangial and endocapillary hypercellularity without immune deposits complicating acute kidney injury. Second, iMCD was treated with prednisolone alone. The patient suddenly developed nephrotic syndrome due to immune-complex glomerulonephritis, not otherwise specified, complicated with acute kidney injury. In the third case, nephrotic syndrome secondary to membranous glomerulonephritis was diagnosed, with a skin rash and IgE antibodies to tocilizumab, and was therefore treated with prednisolone alone. In contrast to the first two cases, the third progressed to end-stage renal disease on hemodialysis. Taken together, this series suggests that clinicians should maintain clinical vigilance for iMCD as a possible underlying component of nephrotic syndrome, since iMCD presents with a variety of renal pathologies. Prompt initiation and continuous administration of tocilizumab are likely key determinants of renal outcomes in such cases. In particular, when tocilizumab is suspended due to infection or in the perioperative period, consideration of its expeditious resumption should be made, taking into account both the withdrawal period and systemic conditions.

Significance of hypergammaglobulinemia in patients with chronic myelomonocytic leukemia

Chronic inflammation is often indicated by a relative increase in the gamma globulin fraction in the serum electrophoresis. In a retrospective study, we analyzed the prevalence of relative hypergammaglobulinemia in 60 patients with chronic myelomonocytic leukemia (CMML), its potential prognostic impact, and potential correlations with laboratory and molecular features. Relative hypergammaglobulinemia (> 20%) was found in 25/60 (42%) patients. The median survival of patients with relative hypergammaglobulinemia was significantly shorter than in patients without hypergammaglobulinemia (10 vs. 24 months, p = 0.018). There was no difference between the groups regarding leukocyte count, hemoglobin value, and platelet count, but a higher prevalence of NRAS mutations and a lower prevalence of ZRSR2 mutations in patients with hypergammaglobulinemia. Our results show that hypergammaglobulinemia is present in a proportion of CMML patients and that this abnormality is associated with poor overall survival. The role of chronic inflammation in the pathophysiology of CMML needs to be further investigated.

Serum IgG4 level during initial treatment as a predictor of relapse in IgG4-related disease

INTRODUCTION

We aimed to investigate the predictors of relapse in immunoglobulin G4-related disease (IgG4-RD), focusing on the serum IgG4 levels during initial treatment.

METHODS

We retrospectively recruited 57 patients with IgG4-RD who were treated with immunosuppressants and elevated serum IgG4 levels in a tertiary hospital between January 2011 and December 2020. They were followed up for ≥ 6 months after initiation of immunosuppressive therapy. Clinical and laboratory findings including serum IgG4 levels (reference value: 6-121 mg/dL) were compared between relapsed (n = 13) and non-relapsed (n = 44) groups. Multivariate Cox regression analysis was used to assess the predictors for relapse. We performed a Kaplan-Meier analysis with a log-rank test to evaluate the cumulative relapse rate for two years.

RESULTS

Median serum IgG4 levels at baseline were 321 mg/dL in the relapsed group and 299 mg/dL in the non-relapsed group. Serum IgG4 levels were normalized after six months in five (38.5%) relapsed and 28 (63.6%) non-relapsed patients. In multivariate Cox regression analysis, the normalization of serum IgG4 levels at six months was associated with a lower risk of relapse, with a hazard ratio of 0.232 (p = 0.019). Central nervous system involvement was associated with the relapse, with a hazard ratio of 21.130 (p = 0.015). The cumulative relapse rate for two years was lower in the normal serum IgG4 group at six months than in the elevated serum IgG4 group at six months (p = 0.027).

CONCLUSION

Our study suggests that normalization of serum IgG4 levels during immunosuppressive treatment for IgG4-RD independently predicts relapse-free outcomes. Thus, monitoring serum IgG4 levels might be used as a marker of prognosis.

Serum Immunoglobulins, Pneumonia Risk, and Lung Function in Middle-Aged and Older Individuals: A Population-Based Cohort Study

Introduction

Immunoglobulins (Igs) play a pivotal role in host defense and prevention of pneumonia. Aging influences serum Ig levels, but the association between Igs and pneumonia in community-dwelling older individuals remains unknown. We evaluated the association of serum IgA, IgG, and IgM with pneumonia and lung function in middle-aged and older individuals.

Methods

We performed Cox and negative binomial regression analyses for the association of Igs with incident pneumonia and pneumonia-related mortality, and recurrent pneumonia respectively. We performed logistic regression analyses for the association between Igs and lung function values. Associations were adjusted for age, sex, smoking, comorbidities, and serum C-reactive protein.

Results

We included 8,766 participants (median age 62.2 years, 57% women, median follow-up 9.8 years). Higher IgA (hazard ratio [HR]: 1.15; 95% confidence interval [95% CI]: 1.00-1.32) and IgG (HR: 1.13; 95% CI: 1.06-1.19) were associated with an increased pneumonia risk. Higher IgG was associated with an increased risk of pneumonia-related mortality (HR: 1.08; 95% CI: 1.01-1.16) and recurrent pneumonia (incidence rate ratio: 1.04; 95% CI: 1.00-1.09). Higher IgA and IgG were also associated with lower forced expiratory volume in one second (FEV₁), lower forced vital capacity (FVC), and an increased odds of preserved ratio impaired spirometry (PRISm, i.e. FEV₁ <80% and FEV₁/FVC ratio ≥70%). No association was seen with an obstructive spirometry pattern.

Discussion

Higher serum IgA and IgG levels were associated with pneumonia, pneumonia-related mortality, and PRISm in middle-aged and older individuals from the general population. Future studies should validate our findings and elucidate underlying pathophysiology.

Investigating the utility of saliva immunoglobulins for the detection of myeloma and using myeloma proteins to clarify partition between oral and systemic immunity

OBJECTIVES

Myeloma is characterised by the presence of monoclonal immunoglobulin (M-protein) and the free light chain (FLC) in blood. We investigated whether these M-proteins and FLC are detectable in myeloma patients' saliva to evaluate its utility for non-invasive screening and monitoring of haematological malignancies.

METHODS

A total of 57 patients with monoclonal gammopathy and 26 age-matched healthy participants provided paired serum and saliva samples for immunoglobulin characterisation and quantification.

RESULTS

Myeloma patients had IgG or IgA M-protein levels ranging up to five times and FLC levels up to a thousand times normal levels of polyclonal immunoglobulins. Despite these highly elevated levels, only two IgG and no IgA M-proteins or FLC could be detected in paired saliva samples. Most patients had reduced levels of serum polyclonal immunoglobulins, but all had normal levels of salivary IgA.

CONCLUSIONS

Immunoglobulin transfer from blood is not determined by levels in the systemic circulation and more likely dictated by periodontal inflammation and the integrity of the oral epithelium. Immunoglobulins secreted by bone marrow plasma cells do not substantially enter saliva, which represents a poor medium for myeloma diagnosis. These findings, along with normal salivary IgA levels despite systemic immunoparesis, support a strong partitioning of oral from systemic humoral immunity.

A 54-Year-Old Woman with Cutaneous Nodules

A 54-Year-Old Woman with Cutaneous NodulesA 54-year-old woman presented with chronic cutaneous nodules and plaques. How do you approach the evaluation, and what is the diagnosis?

Monoclonal gammopathy of clinical significance: what the rheumatologist needs to know

Monoclonal proteins can provide important information on the diagnosis of several non-malignant systemic inflammatory disorders. At low concentration, they most commonly represent monoclonal gammopathy of undetermined significance (MGUS), whereas high concentrations often signify plasma cell myeloma or B-cell lymphoma. However, several rare inflammatory conditions associated with variable concentrations of monoclonal proteins, systemic symptoms, and organ dysfunction also exist. These conditions are termed monoclonal gammopathies of clinical significance (MGCS). Patients with MGCS might present to rheumatologists with undiagnosed systemic inflammatory disorders and the monoclonal protein provides an important, underappreciated clue for diagnosis. In this Review, we provide an approach to distinguishing MGCS from MGUS and lymphoid neoplasms, focusing on four rare MGCS that rheumatologists must recognise: scleromyxedema, Schnitzler's syndrome, idiopathic systemic capillary leak syndrome (also known as Clarkson's disease), and telangiectasias, elevated erythropoietin and erythrocytosis, monoclonal gammopathy, perinephric fluid collections, and intrapulmonary shunting (known as TEMPI) syndrome.

IgG4-related prostatitis manifesting as urinary obstruction in a 28-year-old male

Background

Immunoglobulin G4-related disease (IgG4-RD) is a systemic lymphoproliferative disorder characterized by elevated serum IgG4 levels and tumefactive lesions that can involve nearly every organ system. Involvement of the prostate is rare but has been reported in limited cases.

Case presentation

A 28-year-old man of Asian descent with a history of sinusitis and priapism presented to hospital with rigors and voiding symptoms. He was diagnosed with IgG4-RD one month prior to presentation, following pathological analysis of a submandibular mass that demonstrated chronic sclerosing sialadenitis. On presentation, white blood cell count, C-reactive protein, and prostate serum antigen levels were all within normal limits. Examination was notable for a large, firm prostate, and a foley catheter was inserted. Contrast CT of the abdomen was unremarkable. Further workup revealed elevated serum IgG4 levels (9.22 g/L) and he was subsequently started on prednisone 35 mg daily. Imaging to screen for systemic IgG4-RD involvement demonstrated paravertebral soft tissue involvement and he was given rituximab 1000 mg IV × 2 doses. MRI revealed diffuse prostatitis. Five days after starting prednisone and one day after his first dose of rituximab, he successfully passed trial of void and was discharged home.

Conclusions

IgG4-related prostatitis is a rare and underrecognized manifestation of IgG4-RD. Our case highlights the need to consider IgG4-related prostatitis as an etiology of urinary obstruction in young individuals. Resolution of symptoms following treatment with steroids may be diagnostic of IgG4-related prostatitis, and may potentially avoid the need for invasive diagnostic procedures such as prostate biopsy.

Active IgG4-related disease with bone marrow involvement: a report of 2 cases and case-based review

IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory disease, histopathologically characterized by dense lymphoplasmacytic infiltration rich in IgG4-positive plasma cells in affected organs. Classic hematologic presentations including lymphadenopathy, eosinophilia and polyclonal hypergammaglobulinemia are common, whereas bone marrow involvement of IgG4-RD is rarely reported. Here we present two patients of multi-organ IgG4-RD with bone marrow involvement, one on bone marrow biopsy, and the other on PET/CT. Presentations of other organ involvement included biopsy-proven IgG4-related tubulointerstitial nephritis, lymphadenopathies, submaxillary glands, arteritis, asthma, dysosmia, and constitutional symptoms. Bone marrow involvement was initially suspected due to leukopenia, anemia and thrombocytopenia in case#1, and was finally confirmed by histological evidence of significant IgG4-positive plasma cells infiltration in bone marrow. In case#2, we incidentally observed high uptakes of multi-bone marrow on ¹⁸F-FDG-PET/CT, with the maximum SUV value similar to that of the kidneys, submaxillary glands and hilar, mediastinal lymph nodes by ¹⁸F-FDG-PET/CT. Symptoms and all the hematologic presentation improved rapidly in both patients after steroids initiation. These two cases illustrate the rare bone marrow involvement in active IgG4-RD accompanied by other hematologic syndromes. The significance of disease pathogenesis is worthy of further study.

IgG4-Related Sclerosing Cholangitis: Rarely Diagnosed, but not a Rare Disease

IgG4-related sclerosing cholangitis, a biliary manifestation of an IgG4-related disease, belongs to the spectrum of sclerosing cholangiopathies which result in biliary stenosis. It presents with signs of cholestasis and during differential diagnosis it should be distinguished from cholangiocarcinoma or from other forms of sclerosing cholangitis (primary and secondary sclerosing cholangitis). Despite increasing information and recently established diagnostic criteria, IgG4-related sclerosing cholangitis remains underdiagnosed in routine clinical practice. The diagnosis is based on a combination of the clinical picture, laboratory parameters, histological findings, and a cholangiogram. Increased serum IgG4 levels are nonspecific but are indeed a part of the diagnostic criteria proposed by the Japan Biliary Association and the HISORt criteria for IgG4-SC. High serum IgG4 retains clinical utility depending on the magnitude of elevation. Approximately 90% of patients have concomitant autoimmune pancreatitis, while 10% present with isolated biliary involvement only. About 26% of patients have other organ involvement, such as IgG4-related dacryoadenitis/sialadenitis, IgG4-related retroperitoneal fibrosis, or IgG4-related renal lesions. A full-blown histological finding characterized by IgG4-enriched lymphoplasmacytic infiltrates, obliterative phlebitis, and storiform fibrosis is difficult to capture in practice because of its subepithelial localization. However, the histological yield is increased by immunohistochemistry, with evidence of IgG4-positive plasma cells. Based on a cholangiogram, IgG-4 related sclerosing cholangitis is classified into four subtypes according to the localization of stenoses. The first-line treatment is corticosteroids. The aim of the initial treatment is to induce clinical and laboratory remission and cholangiogram normalization. Even though 30% of patients have a recurrent course, in the literature data, there is no consensus on chronic immunosuppressive maintenance therapy. The disease has a good prognosis when diagnosed early.

Malignancy Risk of Immunoglobin G4-Related Disease: Evidence from a Large Cohort Multicenter Retrospective Study

Introduction

The aim of this work was to evaluate the prevalence of malignancies in a multicenter cohort of Chinese patients with immunoglobulin G4-related disease (IgG4-RD) and to identify the related risk factors of malignancy in IgG4-RD patients.

Methods

We retrospectively analyzed 602 IgG4-RD patients who were recruited in five medical centers from 2009 to 2020. Standardized prevalence ratios (SPRs) against the general Chinese population were calculated along with 95% confidence intervals (CIs). We identified the risk factors of malignancy in IgG4-RD and calculated the odds ratios (ORs) of different factors. We then developed and validated a prediction model for malignancy risk of IgG4-RD based on our cohort.

Results

We observed a significantly increased prevalence of total malignancies in this cohort compared to the general Chinese population (SPR 8.66 [95% CI 5.84, 12.31]). Logistic regression analysis indicated that eosinophil percentage (OR 1.096 [95% CI 1.019–1.179], P = 0.016), serum albumin-to-globulin ratio (AGR) (OR 0.185 [95% CI 0.061–0.567], P = 0.002) and autoimmune pancreatitis (OR 2.400 [95% CI 1.038–5.549], P = 0.041) were three potential risk factors of malignancy in IgG4-RD patients. Four predictors were included in our final prediction model: age at IgG4-RD diagnosis, eosinophil percentage, AGR and autoimmune pancreatitis. The nomogram performed well in the internal validation cohort, with a concordance index (C-index) of 0.738.

Conclusions

A significantly increased prevalence of total malignancies was observed in our multicenter cohort. Eosinophil percentage and autoimmune pancreatitis are risk factors, whereas AGR is negatively associated with malignancy in IgG4-RD. A prediction model for malignancy risk of IgG4-RD was first developed and validated in our study.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40744-021-00326-8.