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Cutaneous Lymphomas
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Emily Correia, Shalini Krishnasamy, Neda Nikbakht
Laboratory studies: Histopathologically, PCMZL shows nodular to diffuse infiltrates of atypical marginal zone B-cells (small lymphocytes with irregular nuclei and abundant pale cytoplasm), reactive T-cells, and plasma cells. The infiltrate may be seen in the dermis and subcutis and may be accompanied by surrounding lymphoid follicles and germinal centers. Reactive plasma cells can be found at the periphery of the infiltrate (Figure 22.11). If plasma cells predominate, it is classified as a PCMZL plasmacytic variant. Immunophenotypically, marginal zone B cells express positivity for CD20 and Bcl-2. Additionally, they are Bcl-6−, CD10−, CD79a+, MUM1−, and CD5−. The reactive germinal centers are Bcl-6+, CD10+, and Bcl-2−, and plasma cells are CD138+ and CD79a+. Immunoglobulin light chain restriction or B-cell monoclonality is observed in malignant marginal zone B cells.
Mucosal B cells and their function
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Jo Spencer, Edward N. Janoff, Per Brandtzaeg
The structure of GALT is similar throughout the gastrointestinal tract with prominent B-cell follicles with intervening T-cell zones. CD4+ T cells in the outermost zone intermingle and interact with antigen-exposed B cells. GALT contains a marginal zone that resembles the splenic marginal zone and is surrounded by and merged with the memory B-cell population (Figure 10.1). Splenic and GALT marginal zone B cells are similar morphologically and are medium-sized cells with cleaved nuclei. These B cells are CD27+IgM+ and do not express high levels of IgD. Splenic marginal zone B cells have mutations in their IgHV genes that are acquired in the germinal centers of GALT. The GALT marginal zone also contains B cells with mutations in IgHV. Internal to and overlapping with the marginal zone is the mantle zone of IgD high naive B cells. The broadest aspect of the often narrow, crescent-shaped mantle zone faces the antigen-exposed FAE. Memory B cells expressing predominantly IgA or IgM (but not IgD) are located on the periphery of the B-cell area of GALT. At the center of the follicle is the germinal center. B cells proliferate and mutate in the cell-dense dark zone of the germinal center and are selected for further antigen-driven mutation and maturation by T-follicular-helper (TFH) cells in the light zone.
The Non-Hodgkin’s Lymphomas and Plasma Cell Dyscrasias
Published in Harold R. Schumacher, William A. Rock, Sanford A. Stass, Handbook of Hematologic Pathology, 2019
Lynne V. Abruzzo, L. Jeffrey Medeiros
These neoplasms are believed to arise from splenic marginal-zone B cells, and are closely related to other marginal-zone B-cell lymphomas. Splenic marginal zone lymphoma (SMZL) is currently recognized as a provisional category in the Revised European-American Classification. Cases with prominent peripheral blood involvement also have been called splenic B-cell lymphoma with villous lymphocytes.
Expression of Homing Receptors in IgM+IgD+CD27+ B Cells and Their Frequencies in Appendectomized and/or Tonsillectomized Individuals
Published in Immunological Investigations, 2023
Diana Bautista, Consuelo Romero-Sánchez, Manuel Franco, Juana Angel
Human marginal zone B cells (MZBC) respond to encapsulated blood-borne pathogens (Kruetzmann et al. 2003) and are altered in different pathologies, highlighting their importance in immunity (Jenks et al. 2018; Liechti et al. 2019; Tull et al. 2021; Woodruff et al. 2020). In children, MZBC have been reported to have a pre-diversified repertoire of immunoglobulin (Ig) genes in the absence of germinal centers (GC) or spleen (Reynaud et al. 2012; Weller et al. 2001, 2004), suggesting the presence of alternate places where the diversification of the repertoire takes place, as occurs in the intestine of rabbits (Weill et al. 2009; Yeramilli and Knight 2013). Although the spleen is the main organ where MZBC are located in humans (Lewis et al. 2019; Zhao et al. 2018), other potential zones equivalent to the marginal zone (MZ) have been identified in the inner wall of the subcapsular sinus of the lymph nodes (Cerutti et al. 2013) and subepithelial regions of the appendix (part of the GALT “Gut Associated Lymphoid Tissue”) and tonsils (part of Waldeyer’s ring and NALT “Nasal Associated Lymphoid Tissue”) (Lettau et al. 2020; Zhao et al. 2018). How MZBC recirculate once they are stimulated in these organs is unknown, but clonal relationships exist between MZBC found in spleen and GALT, suggesting that recirculation between these organs is possible (Mandric et al. 2020; Meng et al. 2017; Zhao et al. 2018).
Optic nerve infiltration in systemic non Hodgkin lymphoma
Published in Orbit, 2023
Cassie A. Cameron, Valerie Juniat, Jessica Y. Tong, John L. Crompton, Garry Davis, Sandy Patel, Dinesh Selva
Systemic NHL arising in the CNS is relatively scarce, constituting approximately 10% of cases, of which only 5% develop optic nerve involvement.15–17 Kim et al. proposed a revised classification system for optic nerve lymphoma comprising four distinct categories; 1) isolated/primary optic nerve involvement; 2) optic nerve involvement with CNS lymphoma; 3) optic nerve involvement with systemic lymphoma; and 4) optic nerve involvement with primary intraocular lymphoma.18 Systemic lymphoma with optic nerve metastasis, as seen in our case, is rare.18 Within the subgroups of NHL, marginal zone B cell CNS lymphoma is typically indolent in nature, presenting with gradually progressive neurological symptoms and focal seizures, in contrast to the aggressive clinical course and high mortality of diffuse large B-cell disease.19,20
HSC70 is a novel binding partner involved in the capture of immunoglobulins on B cells in the NOD mouse
Published in Autoimmunity, 2022
Emma Renman, Rifat Ekici, Mia Sundström, Kristina Lejon
B cells are essential in the humoral immune defense with a prime role to secrete antibodies that are distributed peripherally in order to neutralise and opsonise foreign antigens. In addition, the B cell subtypes follicular B cells and, in particular, marginal zone B cells can capture and transport antigen-immunoglobulin immune complexes (ICs) through surface expression of complement receptors [1,2]. Marginal zone B cells can further shuttle between the marginal zone and follicles in the spleen [3] and deliver ICs to follicular dendritic cells for further activation of the immune system [1]. Studies have also shown that B cells are involved in the endocytosis of foreign antigen-antibody complexes through an Fc(αμ)R-dependent mechanism [4] and activated B cells can through membrane transfer share their B cell receptors with bystander B cells [5]. Thus, the role of B cells in the immune system is undoubtedly versatile and indispensable for a balanced immune homeostasis.