SERUM IgG4

IgG4-related disease, a complex fibro-inflammatory condition impacting various organ systems, is characterized by notable presentations such as enlarged major salivary and lacrimal glands, orbital disease, autoimmune pancreatitis, retroperitoneal fibrosis, and tubulointerstitial nephritis. In this comprehensive review, particular emphasis is placed on the hematologic aspects of IgG4-related disease, including lymphadenopathy, eosinophilia, and polyclonal hypergammaglobulinemia. Hematologists must exercise heightened vigilance, given the disease’s propensity to mimic other conditions like multicentric Castleman disease, lymphoma, plasma cell neoplasms, and hypereosinophilic syndromes, which could lead to misdiagnosis. While serum protein electrophoresis and IgG subclasses serve as valuable initial tests, obtaining a definitive histological diagnosis is crucial for confirmation and differentiation from mimicking conditions. Essential histopathological features encompass a dense, polyclonal lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis. It’s noteworthy that bone marrow and lymph nodes prove suboptimal for histological confirmation. Treatment approaches typically involve corticosteroids, though with a consideration of inducing new-onset or exacerbating existing diabetes in about 40% of patients. Rituximab displays high initial response rates, although durable remissions remain elusive. Severe, refractory cases may call for more intensive lymphoma chemotherapy, while exploration of targeted therapies against plasmablasts, IgE, and other disease biomarkers holds promise for future advancements in treatment modalities. This review underscores the crucial role of vigilant monitoring and accurate histological confirmation in navigating the complexities of IgG4-related disease, aligning with the precision standards upheld by Hypro Diagnostics.