[Differential diagnosis of IgG4-related disease]

IgG4-related disease is a chronic autoimmune fibro-inflammatory disease characterized by the presence of lymphoplasmacytic infiltrate, storiform fibrosis, obliterating phlebitis, increased number of IgG4+ cells in tissue, and, in most cases, an elevated serum IgG4 level. This disease often affects the pancreas, salivary glands and lymph nodes, but can involve almost any tissue. Its etiology is still unclear, the central role in the pathogenesis belongs to B-lymphocytes, T2-helpers, interleukins 1-β, 4, 5, 10, 13 and tumor growth factor 1-β. The ambiguous clinical picture and frequent simultaneous involvement of several organs make it difficult to diagnose, so biopsy plays a leading role in making a diagnosis. The characteristic microscopic picture, the presence of certain populations of lymphocytes are key criteria in establishing the correct diagnosis.

[IgG4-related ophthalmopathy]

IgG4-related disease is a chronic inflammatory fibrosing disease of unknown etiology, characterized by the presence of volumetric lesions that can clinically simulate malignant tumors, a pronounced IgG4-positive lymphoplasmacytic infiltrate, and an increase in the level of IgG4 in the blood serum. A special form of the disease is IgG4-related ophthalmopathy, which requires differential diagnosis with inflammatory pseudotumor, lymphoma and granulomatous polyangiitis. 7 clinical cases of IgG4-related ophthalmopathy are presented. It has been shown that follicle-like structures with the structure of a lymph node are formed in the tissues of the orbit. Along with a large number of cells in the inflammatory infiltrate expressing CD138, IgG and IgG4, there are CD8+ and CD68+ cells. IgG4-related ophthalmopathy is a rare manifestation of IgG4-related disease. Its morphogenesis involves not only IgG, IgG4 and CD138 positive plasma cells, which are diagnostic. CD8 and CD68- positive cells are involved too. They persisted in large quantity in the lymphohistiocytic infiltrate. The study of the lymphocyte population can help in revealing the pathogenesis and morphogenesis of this rare disease.

[Features of the development of latent autoimmune diabetes in adults (LADA)]

The study of the sociomedical problems of diabetes mellitus led to the discovery of latent autoimmune diabetes in adults (LADA), a special form of the disease. The slow onset of the disease, the clinical signs of type 2 diabetes mellitus concurrent with the autoantibody pancreatic β-cell destruction mechanism that is characteristic of type 1 diabetes. Genetic factors play an important role in the genesis of the disease. Insulitis concurrent with intact or hypertrophic islets of the gland originally develops morphologically. Subsequently, the phenomena of islet atrophy and sclerosis are progressive. The disease is typical for young people (generally those aged 25-35 years) with normal body mass index, low blood C-peptide levels, with antibodies against β-cells, primarily to glutamate decarboxylase, being detected. Insulin preparations should be used to treat these patients.