The Role of Regulatory T Cells in the Onset and Progression of Primary Sjögren's Syndrome.

Regulatory T cells (Tregs) play a key role in maintaining immune balance and regulating the loss of self-tolerance mechanisms in various autoimmune diseases, including primary Sjögren's syndrome (pSS). With the development of pSS primarily in the exocrine glands, lymphocytic infiltration occurs in the early stages, mainly due to activated CD4+ T cells. Subsequently, in the absence of rational therapy, patients develop ectopic lymphoid structures and lymphomas. While the suppression of autoactivated CD4+ T cells is involved in the pathological process, the main role belongs to Tregs, making them a target for research and possible regenerative therapy. However, the available information about their role in the onset and progression of this disease seems unsystematized and, in certain aspects, controversial. In our review, we aimed to organize the data on the role of Tregs in the pathogenesis of pSS, as well as to discuss possible strategies of cell therapy for this disease. This review provides information on the differentiation, activation, and suppressive functions of Tregs and the role of the FoxP3 protein in these processes. It also highlights data on various subpopulations of Tregs in pSS, their proportion in the peripheral blood and minor salivary glands of patients as well as their role in the development of ectopic lymphoid structures. Our data emphasize the need for further research on Tregs and highlight their potential use as a cell-based therapy.

Simultaneous Occurrence of Rosai-Dorfman Disease and Nodal Marginal Zone Lymphoma in a Patient with Sjögren's Syndrome.

We present an exceptionally rare case of co-occurrence of Rosai-Dorfman disease (RDD) and nodal marginal zone lymphoma (NMZL) in a 60-year-old Caucasian female with a 20-year course of Sjögren's syndrome (SS). In response to treatment for lymphoma, the patient presented a short positive response, followed by a rapid progression of the disease accompanied by the development of the peripheral facial nerve palsy. We failed to detect Epstein-Barr virus (EBV) in the NMZL/RDD sample by EBV-encoded RNA (EBER) in situ hybridization but identified genomic DNA of EBV by polymerase chain reaction. A second biopsy revealed EBV-positive diffuse large B-cell lymphoma (DLBCL), not otherwise specified. The identical clonal immunoglobulin heavy chain gene rearrangements in the NMZL and DLBCL pointed to their clonal relationship. Though the role of EBV in the pathogenesis of some lymphomas is well-known, there have been only few cases of EBV-induced transformation of low-grade B-cell lymphoma into high-grade lymphoma and no cases of a patient with an NMZL background. To our knowledge, this is the first report of a concomitant occurrence of RDD and NMZL in a SS patient.

Unusual course of generalized lymph node primary plasmacytoma in a patient with Sjögren's syndrome: a case report.

BACKGROUND: Primary lymph node plasmacytoma is a rare disease that typically involves lymph nodes of the neck. In only 15% of cases is the disease generalized. Here, we present a case of generalized lymph node plasmacytoma in a patient with Sjögren's syndrome with an unusual course. CASE PRESENTATION: A 48-year-old white woman presented to our hospital with enlargement of groups of lymph nodes, liver, and spleen. Her medical history was consistent with a 12-year course of Sjögren's syndrome. Blood and urine immunochemistry showed a massive (72 g/l) M-gradient formed from immunoglobulin Aκ in the serum and monoclonal free κ-type light chains in her urine. A skeletal X-ray revealed no bone destruction. Cytological and histological bone marrow assays showed no signs of plasma cell infiltration. The microarchitecture of her neck and inguinal lymph nodes was destroyed. Only small remnants of B cell follicles were found, while the interfollicular areas were expanded and infiltrated by CD138, MuM1, CD43, and IgAκ-positive plasma cells. After nine cycles of doxorubicin, cyclophosphamide, vincristine, and prednisolone chemotherapy, complete remission was achieved. However, the lymphoma relapsed 3 months later, with histological verification in her femoral lymph node. Despite the absence of subsequent adequate therapy, she gradually achieved complete remission of plasmacytoma with the disappearance of paraproteins. CONCLUSIONS: Currently, primary lymph node plasmacytoma is generally considered a nodal marginal zone lymphoma with an extensive plasmacytic differentiation. In our case, despite the critical histological and immunohistochemical evaluation of three lymph node biopsies from different anatomical areas at different times, no signs of nodal marginal zone lymphoma were found. An 18-year follow-up of our patient with primary lymph node plasmacytoma demonstrated an extremely unusual clinical course. Initially, primary lymph node plasmacytoma was refractory to chemotherapy. However, subsequently, she underwent a complete spontaneous remission of plasmacytoma.