A case of simultaneous onset of highly active systemic lupus erythematosus and IgG4-related renal disease

IgG4-Related Disease (IgG4-RD) Autoimmune Pancreatitis (AIP) as an Initial Presentation of Systemic Lupus Erythematosus (SLE)

Acute pancreatitis stemming from IgG4-Related Disease (IgG4-RD) seldom coincides with Systemic Lupus Erythematosus (SLE), highlighting the importance of investigating autoimmune conditions in patients with IgG4-RD. We present the case of a 57-year-old male with a medical history notable for hypertension, photosensitivity, arthritis, and malar rash, who presented with 6 weeks of persistent epigastric pain. Computed Tomography (CT) of the abdomen revealed hallmark features such as fat stranding around the pancreatic tail and gallbladder wall thickening, confirming the diagnosis of acute pancreatitis and cholecystitis. Post-cholecystectomy, histopathological examination of the gallbladder displayed IgG4-positive staining in multiple vessels, accompanied by perivascular inflammation and fibrinoid necrosis infiltrated by lymphocytes and neutrophils, confirming the diagnosis of IgG4-RD. Subsequent evaluation prompted by systemic manifestations revealed an ANA titer of 1:5120 and a dsDNA titer of 1:80, leading to the diagnosis of SLE. The patient later developed mononeuropathy, which improved upon initiation of immunosuppressive therapy. This case underscores the intricate interplay between IgG4-RD and SLE, an association documented to a limited extent in literature, thereby emphasizing the imperative of considering alternative autoimmune diseases with manifestations akin to IgG4-RD.

Plasma Cell-rich Nephritis with a Systemic Polyclonal Lymphoproliferative Disorder, Mimicking Idiopathic Multicentric Castleman Disease, Systemic Lupus Erythematosus, and IgG4-related Disease

Idiopathic multicentric Castleman disease (iMCD), systemic lupus erythematosus (SLE), and IgG4-related disease (IgG4-RD) can cause lymphadenopathy with renal involvement. As no gold standards have been set for diagnosing these conditions, diagnoses can be made by excluding other conditions. However, some cases are difficult to identify. A 60-year-old man presented with lymphadenopathy, renal dysfunction, and hypocomplementemia. Autoimmune pancreatitis and iMCD had been suspected. A renal biopsy revealed immune complex-mediated glomerulonephritis superimposed on endothelial injury and plasma cell-rich tubulointerstitial nephritis with storiform-like fibrosis. While the features of iMCD, SLE, and IgG4-RD were present, a clear classification could not be achieved.

Pharmacological Management of IgG4-Related Disease: From Traditional to Mechanism-Based Targeted Therapies

IgG4-related disease (IgG4-RD) is an immune-mediated disorder characterized by organ enlargement and dysfunction. The formation of tertiary lymphoid tissues (TLTs) in affected organs is crucial for understanding IgG4-RD, as T follicular helper (Tfh) 2 cells within TLTs drive IgG4+B cell differentiation, contributing to mass formation. Key cytokines IL-4 and IL-10, produced by Tfh2 cells, are essential for this process. Additionally, cytotoxic T cells and M2 macrophages significantly contribute to inflammation and fibrosis in the lesions. These insights into IgG4-RD have led to the development of innovative targeted therapies. While glucocorticoids are effective in many cases, they often cause disease flares during tapering and rarely result in long-term, treatment-free remissions. Long-term glucocorticoid use poses significant challenges owing to potential side effects, particularly in older patients who may already have complications such as diabetes and atherosclerotic diseases. In contrast, targeted therapies offer a promising alternative, potentially providing more effective disease control with fewer side effects. Current research is exploring several exciting approaches, including B-cell depletion, targeted immunomodulation of B cells, Bruton's tyrosine kinase inhibition, disruption of co-stimulation pathways, targeting the SLAMF7 cytokine or its receptor blockade (BAFF, IL-4, or IL-6), and JAK-STAT signaling pathway inhibition. These emerging strategies hold the promise of improving patient outcomes and advancing the management of IgG4-RD.

Discriminative features of immunoglobulin G4-related disease (IgG4-RD) and associated autoimmune rheumatic diseases (ARDs) in a nationwide observational cohort: study from the Egyptian College of Rheumatology

OBJECTIVE

The objective of this study is to present the clinical characteristics of immunoglobulin G4-related diseases (IgG4-RD) patients and describe associated overlap with autoimmune rheumatic diseases (ARDs).

PATIENTS AND METHODS

This cross-sectional study included 81 patients with IgG4-RD who were recruited from 13 specialized rheumatology departments and centers across the country in collaboration with the Egyptian College of Rheumatology (ECR). Patients underwent a thorough history-taking and clinical examination. We reviewed patients' medical records and recorded the medications they used. The presence of comorbidities or cumulative manifestations was determined. Laboratory investigations, imaging, and biopsy histopathology were assessed.

RESULTS

The mean (SD) age was 41.4 (14.6) years with 60 females and 21 males (F/M 2.9:1). The diagnosis was definite in 50 (61.7%), probable in 19 (23.5%), and possible in 12 (14.8%). The most common cumulative clinical features are IgG4-related respiratory disease in 19 (23.5%), autoimmune pancreatitis (AIP) in 18 (22.2%), and Riedel's thyroiditis in 17 (21.0%). Approximately 80% were administered corticosteroids, whereas 40% received azathioprine as adjunct therapy. Approximately 16% developed a relapse with this combination and transitioned to an alternative steroid-sparing treatment. Twelve individuals (14.7%) required rituximab. Fifty percent of patients receiving rituximab (six patients) exhibited complete improvement, while the remaining had partial improvement. Ten (12.3%) patients had associated ARDs: five (6.2%) with systemic lupus erythematosus (SLE), four (4.9%) with rheumatoid arthritis (RA), and one with vasculitis. Of the four patients with associated RA, three were rheumatoid factor (RF) negative. IgG4 was in all cases, RF was positive in 18.5%, and antinuclear antibody was in 14.7%.

CONCLUSION

IgG4-RDs exhibit a wide range of presentations, closely associated with ARDs. Awareness among clinicians about this condition will increase their consideration and rate of prompt diagnosis, which is essential to prevent damage to critical organs. Key Points • IgG4-RDs have a myriad spectrum of presentation with a close link to rheumatic diseases. • Awareness among clinicians about this condition will increase their consideration and rate of prompt diagnosis. • The lack of reliable biomarkers for this condition has been an important hurdle for diagnosis.

An overlapping case of IgG4-related disease and systemic lupus erythematosus treated with belimumab: a case-based review

IgG4-related disease (IgG4-RD) is a systemic condition in which IgG4+ plasma cell infiltration and fibrosis cause organ swelling and lead to diverse clinical manifestations. Although IgG4-RD typically responds to glucocorticoids (GCs), relapse during tapering occurs and an early GC-sparing approach might therefore be beneficial. Systemic lupus erythematosus (SLE) is a chronic inflammatory disease with multiple symptoms that is also treated with GCs as a first-line therapy. Recently, belimumab, a recombinant human IgG-1λ monoclonal antibody that inhibits B-cell activating factor, was approved, but reports of use for IgG4-RD are scarce. Here, we present a rare case of IgG4-RD complicated with SLE which was successfully treated with belimumab. A 67-year-old man was diagnosed with IgG4-RD based on a high serum IgG4 level and histopathological findings. Furthermore, he had pericardial effusion on echocardiography, and laboratory tests revealed thrombocytopenia, autoimmune hemolysis, positive anti-nuclear antibodies, positive anti-DNA antibodies, and hypocomplementemia. These data led to an SLE diagnosis. Treatment was started with prednisolone at 40 mg/day, plus hydroxychloroquine, which initially improved both the SLE and IgG4-RD symptoms. During the GC tapering, belimumab was added and clinical symptoms resolved completely. Our case and the literature review summarize reported rare overlapping cases of IgG4-RD and SLE and suggest that belimumab is a promising candidate for the treatment of IgG4-RD.