Impact of the microenvironment on the pathogenesis of mucosa-associated lymphoid tissue lymphomas

Primary pulmonary extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type: a case report and literature review

Primary pulmonary mucosa-associated lymphoid tissue (MALT)-derived lymphoma is a low-grade B-cell non-Hodgkin's lymphoma. It is rare with unclear clinical and imaging findings, requiring biopsy or surgery for diagnosis. Here, we provide a new case to learn the symptoms, diagnosis and treatment of primary pulmonary MALT lymphoma. The patient was a 51-year-old male. During the annual physical examination in 2019, a shadow in the lower lobe of the right lung was accidentally found in his chest computed tomography image. In 2020, the size and density of the shadows increased, which was suspected to be lung adenocarcinoma. The patient underwent video-assisted thoracoscopic surgery and segmental resection. Pathological examination showed residual germinal centers around the tumor cells, and many inflammatory cells had diffusely infiltrated, mainly monocyte-like B cells. Immunohistochemical analysis showed that CD3, CD20, Bcl-2, CD43, CK-pan and CD23 were positive, while BCL-6, CD5, CD10, c-myc and cyclin D1 were negative. The patient was diagnosed with MALT extranodal marginal zone B-cell lymphoma. The patient did not receive chemotherapy or radiotherapy after the operation but was still under close observation. Primary pulmonary MALT develops slowly and tends to be inert and spontaneous. Due to the lack of specific clinical symptoms and imaging findings, it can easily be misdiagnosed as tuberculosis, lung cancer, or infection. Thoracoscopic resection may be a good choice for the diagnosis and treatment.

In Peripheral Blood Mononuclear Cells Helicobacter pylori Induces the Secretion of Soluble and Exosomal Cytokines Related to Carcinogenesis

Helicobacter pylori promotes the secretion of cytokines that regulate inflammation and carcinogenesis. Immune cells secrete cytokines into the extracellular medium or packaged in exosomes. The objective of this study was to analyze the profile of soluble and exosomal cytokines that were secreted by human peripheral blood mononuclear cells (PBMCs) that were infected with H. pylori and to build a network of interaction between cytokines and cellular proteins. PBMCs were obtained by density gradient centrifugation and infected with H. pylori for 24 h. The infection was verified by immunofluorescence and Western blot for CagA. The exosomes were obtained from culture supernatant by ultracentrifugation and characterized by transmission electron microscopy, particle size analysis, and Western blot for CD9 and CD81. Cytokines were quantified using a multiplex immunoassay in the culture supernatant, intact exosomes, and lysed exosomes. H. pylori adheres to lymphocytes and translocates CagA. In PBMCs, H. pylori induces an increase in the soluble and exosomal IL-1β, IL-6, TNF-α, IL-10, IL-17A, IL-21, and IL-22. The protein-protein interaction (PPI) network shows that soluble and exosomal cytokines interact with proteins that participate in signaling pathways such as NF-κB, MAPK, PI3K-Akt, Jak-STAT, FoxO, and mTOR, that are related to carcinogenesis; moreover, TNF-α had the highest number of interactions. Cytokine-loaded exosomes represent another means of intercellular communication that is activated by H. pylori to stimulate inflammation, carcinogenesis, or cancer progression. Cytokine-loaded exosomes are likely to be associated with extragastrointestinal diseases of inflammatory origin.