Short article: The endoscopic and histologic findings of infants who have experienced brief resolved unexplained events. 15, 109119 (2022). doi: 10.1371/journal.pone.0182224. Case Report: Intestinal Nodular Lymphoid Hyperplasia as First Manifestation of Activated PI3K Syndrome Due to a Novel. What does a pathologist do when encountering a lymphoid aggregate in the GI mucosa? Inherent production of retinoic acid and TGF- (typical for gut-associated DCs) induces expression of gut-homing molecules and favor IgA switch during maturation of B cells in folicules. organised GALT made up from folicules such as Peyers patches, mesenteric lymph nodes and even more organised appendix. They are derived from nave T cells that encounter antigens in the periphery (typically antigens displayed by DC in the Peyers patches). These epithelial cells are covered by a layer of glycocalyx on their luminal surface so as to protect cells from the acid pH. 463, 637642 (2013). [23] Robust engagement of a variety of lymphoid cells patrolling the epithelial layer also reflects evolutionary pressure and arms race between immune systems and pathogens escaping its control. Some common and less common diseases and disorders of the lymphatic system include: To keep your lymphatic system strong and healthy, you should: Call your doctor if you experience fatigue (extreme tiredness) or have unexplained swelling that lasts more than a few weeks or interferes with your daily activities. Antibody secreting cells are critically dependent on integrin 47/MAdCAM-1 for intestinal recruitment and control of the microbiota during chronic colitis. Peyer's patches are small masses of lymphatic tissue found throughout the ileum region of the small intestine. 2017 Aug 1;12(8):e0182224. Nature 597, 250255 (2021). Diversification of memory B cells drives the continuous adaptation of secretory antibodies to gut microbiota. Terminal ileitis is the inflammation of the terminal end of the ileum, which is the last section of the small intestine before it leads into the large intestine. Sci. Alternative pathways for the development of lymphoid structures in humans. Immune profiling of human gut-associated lymphoid tissue identifies a role for isolated lymphoid follicles in priming of region-specific immunity. [2][6] Although in these crypts conventional enterocytes are the dominant type of cells, Paneth cells can also be found. Care Med. Scher, J. U. et al. Berlin, C. et al. Gut 38, 724732 (1996). J. Exp. Unauthorized use of these marks is strictly prohibited. [26] They provide the first line of defense in case of pathogen crossing the epithelial barrier. However, the cells found in a lymph node may be described as a lymphoid aggregate if only a small sample is removed and the normal organization of the lymph node cannot be seen. Marzollo A, Bresolin S, Colavito D, Cani A, Gaio P, Bosa L, Mescoli C, Rossini L, Barzaghi F, Perilongo G, Leon A, Biffi A, Cananzi M. Front Pediatr. Microscopically, Peyer's patches appear as oval or round lymphoid follicles (similar to lymph nodes) located in the mucosa layer of the ileum and extend into the submucosa layer. Carroccio A, Iacono G, Di Prima L, Ravelli A, Pirrone G, Cefal AB, Florena AM, Rini GB, Di Fede G. Clin Gastroenterol Hepatol. Gastroenterology 128, 687694 (2005). B cells and tertiary lymphoid structures as determinants of tumour immune contexture and clinical outcome. [2] The functional importance of GALT in body's defense relies on its large population of plasma cells, which are antibody producers, whose number exceeds the number of plasma cells in spleen, lymph nodes and bone marrow combined. Gastroenterology 140, 947956 (2011). [10] The adult northern brown bandicoot (Isoodon macrourus) has been described to have both organised and diffuse GALT. 9, 1910 (2018). Google Scholar. The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). 23, 379391 (2017). Because immune cells are in constant touch with bacterial and food antigens, the primary response is set up as tolerogenic. The articles on MyPathologyReport are intended for general informational purposes only and they do not address individual circumstances. Barone, F. et al. Immunol. Wing, J. 21, 343353 (2020). Gut 61, 327 (2012). Immunol. Majority of antigen presenting cells (APCs) in intestine is derived from macrophages, which have very quick turnover. 16, 639649 (2016). These lymphoid cells are produced in the bone marrow and thymus and migrate to the gut to form one of the largest collections of immune cells in the body. While CD20 staining was positive, MUM-1 and Bcl-6 staining were negative. Jorgensen, P. B. et al. [1][4] However, Peyer regarded them as glands which discharged, into the small intestine, some substance which facilitated digestion. Blood 113, 24612469 (2009). 40, 413442 (2022). Eur J Gastroenterol Hepatol. Clin. Sci. The small intestine, also small bowel, is a relatively well-behaved piece of machinery from the perspective of pathology. Gut-associated lymphoid tissue (GALT) is a component of the mucosa-associated lymphoid tissue (MALT) which works in the immune system to protect the body from invasion in the gut. Long, Y. et al. Drink plenty of water to stay hydrated so lymph can easily move throughout your body. Some histologic features can help to distinguish reactive lymphoid aggregates from lymphoma (Table 1, Figure 2). Lett. Lymphoid tissue is normally concentrated along the mucosal surfaces of the body (tonsils, Peyer patches) and can also be acquired at sites of chronic antigenic stimulation. Cornes, J. S. Number, size, and distribution of Peyers patches in the human small intestine: Part I The development of Peyers patches. [3] This different distribution of the adaptive organs in the different groups of vertebrates suggests GALT as the very first part of the adaptive immune system in vertebrates. Cell 185, 12081222.e21 (2022). A., Spencer, J. 31, 837851.e10 (2020). Hoch, T. et al. This is a preview of subscription content, access via your institution, Access Nature and 54 other Nature Portfolio journals, Get Nature+, our best-value online-access subscription, Receive 12 print issues and online access, Get just this article for as long as you need it, Prices may be subject to local taxes which are calculated during checkout. Cleveland Clinic is a non-profit academic medical center. Many conditions can affect the vessels, glands, and organs that make up the lymphatic system. To aid in understanding what is meant when lymphoid tissue is described in the pathology report, we provide the following definitions: Lymphoid tissue: A general term to describe a collection of B-cells, T-cells, and support cells. Accessibility Both GALT and mesenteric lymph nodes are sites where the immune response is started due to the presence of immune cells through the epithelial cells and the lamina propria. MALT makes up dome-shaped structures found underlying the mucosa of the gastrointestinal tract . Kuppers, R. & Stevenson, F. K. Critical influences on the pathogenesis of follicular lymphoma. Edwards, J. C. & Cambridge, G. B-cell targeting in rheumatoid arthritis and other autoimmune diseases. Privacy Policy. Clin. To see if your lymphatic system is working as it should, your doctor may use imaging tests such as a CT scan or MRI. Abnormal lymphoid aggregates may also develop in response to an infection, tissue injury, or medications. An atlas of B-cell clonal distribution in the human body. Re-utilization of germinal centers in multiple Peyers patches results in highly synchronized, oligoclonal, and affinity-matured gut IgA responses. Rev. Likewise, lower endoscopy might be additionally performed in patients with suspected FH and LNH of the duodenal bulb, also presenting with lower abdominal symptoms (i.e. Please enable it to take advantage of the complete set of features! USA https://doi.org/10.1073/pnas.2108082118 (2021). R. Soc. PubMed [2], The following examples comprise lymphoid tissues that act as interfaces between immune system and incoming antigens either as food antigens or as pathogenic or commensal microbiotas antigens:[citation needed], GALT can be also divided into two categories considering the structure, from which the function arise. Bowel Dis. High abundance of plasma cells secreting transglutaminase 2-specific IgA autoantibodies with limited somatic hypermutation in celiac disease intestinal lesions. Immunol. Score: 5/5 (44 votes) . 29, 621663 (2011). PubMedGoogle Scholar. Nat. J. Exp. Iacono G, Ravelli A, Di Prima L, Scalici C, Bolognini S, Chiappa S, Pirrone G, Licastri G, Carroccio A. Clin Gastroenterol Hepatol. Natl Acad. CAS It has been suggested that from this existing GALT, and due to the pressure put by commensal bacteria in gut that coevolved with vertebrates, later specializations as thymus, spleen or lymph nodes appeared as part of the adaptive immune system.[2]. Immunol. They are of different origins and follow different maturation processes but share the same GALT role to rapidly respond to pathogens and secrete effector cytokines. Blood-borne human plasma cells in steady state are derived from mucosal immune responses. Your lymphatic system, part of your immune system, has many functions. Hapten-induced colitis is associated with colonic patch hypertrophy and T helper cell 2-type responses. Peyer's patches: These are small masses of lymphatic tissue in the mucous membrane that lines your small intestine. Functional Th1-oriented T follicular helper cells that infiltrate human breast cancer promote effective adaptive immunity. Clipboard, Search History, and several other advanced features are temporarily unavailable. Med. But upon infection or inflammation, the profile of macrophages changes and they start to secrete large amounts of TNF- and become proinflammatory effector cells. Elmentaite, R. et al. Immunology 101, 354363 (2000). Rosser, E. C. et al. In health, the response is intricately balanced to provide active protection against pathogen invasion whilst tolerating food and avoiding inflammation. Others develop as a result of disease or injury. MacDonald, T. T., Spencer, J., Viney, J. L., Williams, C. B. Ananya Datta Mitra MDHooman H. Rashidi MDKaren Matsukuma MD, PhD. [1] They are an important part of gut associated lymphoid tissue usually found in humans in the lowest portion of the small intestine, mainly in the distal jejunum and the ileum, but also could be . Lymphangiomatosis is the presence of multiple or widespread lymphatic vascular malformations. Rev. Nat. The imbalance of circulating follicular helper T cells and follicular regulatory T cells is associated with disease activity in patients with ulcerative colitis. Tull, T. J. et al. MeSH Tertiary lymphoid structures generate and propagate anti-tumor antibody-producing plasma cells in renal cell cancer. Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease. The dynamic interplay between the gut microbiota and autoimmune diseases. Spahn, T. W. et al. Landsverk, O. J. et al. [25], Innate lymphoid cells (ILCs) are the most recently discovered family of innate immune cells and term innate means they do not need antigen receptor gene rearrangement. Nat. J. Immunol. Background: The body then prepares a full body-wide immune response to the pathogen before it is able to spread beyond the intestines. . Small intestine only - 30-50%; Large intestine only - 25-30%; Both small and large intestine - 30-50%; Stomach or duodenum - 50% (typically mild) Rubio, C. A. et al. Maloy, K. J. J. Immunol. Conclusions: 2019, 7546047 (2019). Cell 178, 14931508.e20 (2019). Andersson, R. E., Olaison, G., Tysk, C. & Ekbom, A. Appendectomy and protection against ulcerative colitis. Article Some 20 liters of plasma flow through your bodys arteries and smaller arteriole blood vessels and capillaries every day. Piper, C. J. M. et al. Main article: Obese. Deep analysis of the peripheral immune system in IBD reveals new insight in disease subtyping and response to monotherapy or combination therapy. If you have medical questions or would like to make an appointment or find out about the referral process, please call 800-2-UCDAVIS. Terminal Ileum, Biopsy: - Small bowel mucosa with morphologically benign lymphoid aggregates, negative for significant pathology. 137, 12131214 (2017). These IgA are secreted into the lumen of the gut through the epithelial layer by transcytosis. Nature 542, 110114 (2017). Rev. Such multi-layered protection systems highlights the susceptibility of mucosal sites to invading agents. Anti-47 therapy targets lymphoid aggregates in the gastrointestinal tract of HIV-1-infected individuals. Proc. [24] T cells express TCR receptor made of and subunit and do not recognize antigen peptides presented in the MHC-bound form. Appendectomy and the risk of developing ulcerative colitis or Crohns disease: results of a large case-control study. [5] In order to increase the surface area for absorption, the intestinal mucosa is made up of finger-like projections (villi), covered by a monolayer of epithelial cells, which separates the GALT from the lumen intestine and its contents. PubMed Central Spatiotemporal segregation of human marginal zone and memory B cell populations in lymphoid tissue. Immunol. 1997 Dec;15(4):211-23. Lymphangitis: This is an inflammation of the lymph vessels. The adjuvant GLA-SE promotes human Tfh cell expansion and emergence of public TCR clonotypes. Matysiak-Budnik, T. et al. Gut 72, 4953 (2023). Appendectomy does not decrease the risk of future colectomy in UC: results from a large cohort and meta-analysis. Maintain a healthy lifestyle that includes regular exercise and a healthy diet. 121, 466471 (2000). 2.) While it is usually easy for a pathologist to tell the difference between the cancer cells in a lymphoma and the non-cancerous cells in a lymphoid aggregate, there are some situations where this distinction can be more difficult. It forms a subepithelial dome where large number of B cell follicles with its germinal centers, T cell areas between them in a smaller number and dendritic cells are found. Gut 60, 15201526 (2011). 13, 311 (2020). Mora, J. R. Homing imprinting and immunomodulation in the gut: role of dendritic cells and retinoids. Peyers patch TH17 cells are dispensable for gut IgA responses to oral immunization. Heterogeneity and clonal relationships of adaptive immune cells in ulcerative colitis revealed by single-cell analyses. Last reviewed by a Cleveland Clinic medical professional on 02/23/2020. Commensal microbiota activates immune response as well - in a way that protects host intestinal tissue from damaging it by immune cell reactions. Am. PubMed Conventional intraepithelial cells are thus tissue-resident effector memory T cells, capable of rapid respond with cytolytic activity and release of cytokines such as INF and TNF. Food hypersensitivity as a cause of rectal bleeding in adults. Med. 10, 534 (2019). Immunity 51, 337350.e7 (2019). Transl. The final outcome of T cell populations in healthy individuals differs from the spectrum of T cells resulting from acute infection or chronic inflammation. Immunol. Nat. 11, 447457 (1976). ISSN 1759-5045 (print). In the gut-associated lymphoid tissue, the process of differentiation occurs via presentation of antigens derived from gut microbiota by antigen presenting cells such as dendritic cells or M cells in Peyers patches. Gut Liver 16, 207215 (2022). Immunity 54, 16521664 (2021). Immunol. & Weisel, F. Germinal center selection and the development of memory B and plasma cells. Adv. How to Prepare for a Virtual Doctor Visit, The Ten Best & Worst States for Telehealth. Curr. Malakoplakia has also been described in association with numerous conditions such as tubular adenomas, adenocarcinomas, diverticulosis, ulcerative colitis, neurofibromas, cirrhosis, tuberculosis, stomach ulcers and lymphoid hyperplasia. Jarasvaraparn C, Gallegos MBR, Mulekar MS, Bin Wang, Gremse DA, Crissinger KD. Nat Rev Gastroenterol Hepatol (2023). Lymphoid aggregates are normally found throughout the small and large intestine. 7, eabc5500 (2022). Known as lymphoid nodular hyperplasia (LNH), these aggregates are observed especially in young children and are not associated with clinical symptoms being considered 'physiological'. B cells and the humoral response in melanoma: the overlooked players of the tumor microenvironment. Ulcerative colitis is characterized by a plasmablast-skewed humoral response associated with disease activity. In human subjects about 70% of small intestinal IELs are CD8 + cells. Inappropriate stimulation (typically by segmented filamentous bacteria - SFB) of chronic Th1 or Th17 cell response plays a crucial role in pathological damage to the host. Maglione, P. J. et al. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. & Das, K. M. Autoimmunity in ulcerative colitis (UC): a predominant colonic mucosal B cell response against human tropomyosin isoform 5. Iversen, R. et al. In children presenting with gastrointestinal symptoms the number and size of the lymphoid follicles are increased. Clin. Goc, J. et al. 28, 766779 (2022). Med. Underneath them, there is an underlying layer of loose connective tissue called lamina propria. Gastric involvement is rare. Table 1. The number of Peyer's patches peaks at age 1525 and then declines during adulthood. In this area, the subepithelial dome is separated from the intestinal lumen by a layer of follicle-associated epithelium. Immunity 53, 217232.e5 (2020). Wotherspoon, A. C., Ortiz-Hidalgo, C., Falzon, M. R. & Isaacson, P. G. Helicobacter pylori-associated gastritis and primary B-cell gastric lymphoma. 10, 361 (2019). The primary lymphoid tissues are bone marrow and thymus (sites of lymphocyte development); the normal secondary lymphoid tissues include mucosa-associated lymphoid tissue (MALT, mentioned above) and the lymph node, which both serve similar functions. 35, 879884 (2017). Review article: Chronic constipation and food hypersensitivity--an intriguing relationship. Su, W., Spencer, J. Brandtzaeg, P., Carlsen, H. S. & Halstensen, T. S. The B-cell system in inflammatory bowel disease. Gallo, R. L. Human skin is the largest epithelial surface for interaction with microbes. Intestinal lymphoid nodular hyperplasia in children: the relationship to food allergy. Med. Front. Histopathology of the resected specimen identified a lymphoepithelial lesion with an invasive tendency. Secreted IgAs bind to bacterial toxins and neutralize them as well. Antibody-secreting plasma cells and their immediate precursors generated in GALT disseminate widely to diffusely populate the extensive lamina propria. Brandtzaeg, P., Baklien, K., Fausa, O. Commun. Some happen during development before birth or during childhood. Monteleone, G. et al. A lymphoid aggregate seen under the microscope. Berteloot, L. et al. Hasleton, P. S. The internal surface area of the adult human lung. Gastroenterol. CAS Adv. . Cell Metab. You must consult your own medical professional. Reboldi, A. https://doi.org/10.1126/sciimmunol.abb4432 (2020). Immunol. Atypical lymphoid aggregate: A lymphoid aggregate that lacks the typical morphologic and immunophenotypic features of a reactive lymphoid aggregate but is not diagnostic of lymphoma. Hill, D. L. et al. Macrophages can use their trans-epithelial dendrites (long cytoplasmic extensions) and directly contact epithelial layer and sample luminal bacteria. Jovani, M. & Danese, S. Vedolizumab for the treatment of IBD: a selective therapeutic approach targeting pathogenic a4b7 cells. Interleukin-21 enhances T-helper cell type I signaling and interferon- production in Crohns disease. The secretory component protects secreted antibodies against the digestive milieu in the gut. Mei, H. E. et al. Increased circulating PD-1hiCXCR5 peripheral helper T cells are associated with disease severity of active ulcerative colitis patients. Mucosal Immunol. Randomised placebo-controlled trial of rituximab (anti-CD20) in active ulcerative colitis. Lymphoid aggregates in Crohns colitis and mucosal immunity. 16, 20512067 (2021). Med. Quartier, P. et al. Mucosal Immunol. Pharmacol. Proc. Nat. Abstract Background: Lymphoid aggregates are normally found throughout the small and large intestine. Mucosal Immunol. However, it is essential to keep in mind that distinction between a reactive and a neoplastic lymphoid process is often not possible based on morphology alone. 7, eabm9060 (2022). Expansion of intestinal Prevotella copri correlates with enhanced susceptibility to arthritis. Biol. https://doi.org/10.1038/s41575-023-00755-6, DOI: https://doi.org/10.1038/s41575-023-00755-6. How does a pathologist distinguish a reactive lymphoid aggregate from lymphoma? High microbiota reactivity of adult human intestinal IgA requires somatic mutations. & Walker-Smith, J. 112, 391400 (1972). The lymphoid aggregates are usually noted in the mucosa and submucosa, although they can be located throughout the bowel wall and are characteristically seen in the subserosal fat . & Bemark, M. T cell-independent IgA class switch recombination is restricted to the GALT and occurs prior to manifest germinal center formation. This contains conventional intestinal epithelial cells and a small number of specialized epithelial cells called microfold cells (M cells) in between. Immunity 55, 527541.e5 (2022). Disease is limited to the small intestine in approximately 40-50% of cases, whereas another 30-40% of cases involve both the small intestine and the colon. Google Scholar. [15] T cells, B-cells and memory cells are stimulated upon encountering antigen in Peyer's patches. 27, 463467 (1997). By partnering with patients, healthcare providers, and hospitals, we hope to provide all patients with the tools and knowledge to understand their pathology report. They represent a relative minority of the total intestinal IELs compared with unconventional IELs. Annu. 2023UC Regents. vomiting). Sign up for the Nature Briefing newsletter what matters in science, free to your inbox daily. Martin, J. C. et al. Because of low expression of innate response receptors and co-stimulatory surface molecules, intestinal macrophages do not initiate inflammation. Scand. Nat. Tunable dynamics of B cell selection in gut germinal centres. Immunol. Greenblatt, H. K., Kim, H. A., Bettner, L. F. & Deane, K. D. Preclinical rheumatoid arthritis and rheumatoid arthritis prevention. 2006 Nov 1;24(9):1295-304. doi: 10.1111/j.1365-2036.2006.03125.x. Histologic features that help distinguish reactive lymphoid aggregates from lymphoma. Lymphoid aggregate is a general term used to describe a group of lymphoid (immune) cells such as lymphocytes, plasma cells, and histiocytes. Get the most important science stories of the day, free in your inbox. A reactive lymphoid aggregate is a group of non-cancerous lymphoid cells (immune cells) that are reacting or responding to conditions and signals in their environment. 11, 104 (2020). Article Immunol. Di Niro, R. et al. They perform immune memory in particular tissue even after clearance of pathogen or retreat of inflammation. Histopathology 10, 267283 (1986). This lymphoid area is found beneath a single layer of columnar cells called the follicle-associated epithelium (FAE). Roux-en-Y gastric bypass. The polyps most commonly appear in the small intestine (55% . [24], Unconventional IELs present majority of IEL cells in intestinal epithelial layer and acquire their effector program after exiting thymus as nave cells and encountering antigens in GALT. 233, 210 (2021). It is based on molecular surface properties and the place where they acquire their final effector cytotoxic program. March 24, 2022. About 100 are found in humans. Careers. Impact of bacterial metabolites on gut barrier function and host immunity: a focus on bacterial metabolism and its relevance for intestinal inflammation. In this instance, the pathologist may perform tests, such as immunohistochemistry and flow cytometry, to look for additional clues such as markers that may be expressed by cancer cells but are not expressed by normal, healthy cells. Results: 1899, 5566 (2019). [8] Moreover, basal lamina of follicle-associated epithelium is more porous compared to intestinal villus. Sci. Immunol. Roco, J. Considering the possible co-existence of duodenal and ileo-colonic LNH, upper endoscopy can be recommended in children with suspected FH, especially in those presenting with additional upper abdominal symptoms (i.e. Tumor-reactive antibodies evolve from non-binding and autoreactive precursors. Rep. 23, 9 (2021). Rep. 9, 13574 (2019). Avoid exposure to toxic chemicals like those in pesticides or cleaning products. 35, 11431149 (2020). Nature Reviews Gastroenterology & Hepatology thanks Britta Siegmund, Kathryn Knoop and Hiroshi Ohno for their contribution to the peer review of this work. Rev. Kosoy, R. et al. recurrent abdominal pain) should systematically undergo gastroduodenoscopy and colonoscopy. Salmonella typhi and poliovirus also target this section of the intestine.[16]. Anti-commensal IgG drives intestinal inflammation and type 17 immunity in ulcerative colitis. Helander, H. F. & Fandriks, L. Surface area of the digestive tract revisited. & Isaacson, P. G. The human gut contains a novel population of B lymphocytes which resemble marginal zone cells. & Sollid, L. M. Celiac disease: autoimmunity in response to food antigen. J. Exp. Invest. Curr. Macrophages are prevalent in lamina propria and submucosal deeper layers like muscularis layer. The maturation of B-lymphocytes takes place in the Peyer's patch. This blog does not imply that UC Davis Health endorses the views expressed. consists of an aggregate of lymphoid follicles directly associated with the mucous membrane epithelia. Long, Y. et al. [22] Varied palette of pattern recognition receptors is activated by various signals named PAMP (pathogen associated molecular patterns) or by signals connected to tissue damage named DAMP (damage associated molecular patterns). Lymphoid aggregates are a normal finding in some areas of the body, such as the stomach, small bowel, and colon. In adults, B lymphocytes are seen to dominate the follicles' germinal centers. Jabri, B. Its main function is to induce immune reaction. Ravetch, J. V. Fc receptors. Google Scholar. A. et al. Peyer's . Firstly epithelial cell binds a dimer of IgA via polymeric Ig receptor at the basolateral side and transports it in a vesicle into the luminal space. Curr. Berkowska, M. A. et al. 211, 9871000 (2014). Kuwada, T. et al. The mean total lymphoid follicles and aggregates per biopsy was 0.59 0.32 for study cases and 0.31 0.21 for controls (P = .005) . J. Respir. An integrated multi-omic single-cell atlas of human B cell identity. Immunol. 7, 467477 (2014). Cell Immunol. X 20. 16, 13321339 (2010). Immunol. The authors contributed equally to all aspects of the article. J. Pathol. Nodular lymphoid hyperplasia of the gastrointestinal tract produces multiple discrete mucosal nodules in a variable segment of the small intestine, large intestine, or both. School of Immunology and Microbial Sciences, Kings College London, Guys Campus, London, UK, Department of Microbiology and Immunology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, You can also search for this author in The intestinal lumen contains an abundance of bacteria, viruses and fungi alongside ingested material that shape the chronically active intestinal immune system from early life to maintain the integrity of the gut epithelial barrier. Antibody-secreting plasma cells persist for decades in human intestine. Dunn-Walters, D. K., Isaacson, P. G. & Spencer, J. Sequence analysis of human IgVH genes indicates that ileal lamina propria plasma cells are derived from Peyers patches.