The immune and lymphatic systems, infection and sepsis
Peate Ian, Dutton Helen in Acute Nursing Care, 2020
Lymphocytes are the cells of the lymphatic system. Produced in the bone marrow, they form part of the cell-mediated response to antigens. As their name suggests, they spend most of their life cycle, which is about 2–4 years, within the lymphoid tissues. There are different types and sizes of lymphocytes, T cells and B cells. T cells are produced in the bone marrow, but are matured (or become immunocompetent) within the thymus. B cells are also produced in the bone marrow, but remain there to mature and become immunocompetent (see Figure 12.2). The T and B cells are exposed to antigens, normally in the lymphoid tissue, where they differentiate and mature. Within the T and B cell population, there are a range of cells with differing functions. B cells mediate the humoral or antibody response and T cells mediate the cellular immune response.
Adaptive Tumor Suppression
John Melford in Pocket Guide to Cancer, 2017
Among the components of the adaptive system are specialized white blood cells called lymphocytes of which there are two main types, B-cells and T-cells. These are created in the bone marrow by stem cells, and then circulate in the blood. T-cells migrate to the thymus where they reach maturity, hence the name T-cells. Mature B-cells and T-cells are deployed to lymph nodes and other lymphoid organs where they remain on alert to respond to a pathogen invasion. The lymphatic system consists of an extensive network of vessels that connect lymph nodes, the thymus, the spleen, adenoids, and tonsils. Lymph vessels are like arteries and veins that carry vital supplies of blood to all parts of the body. However, they are much finer and carry a colorless liquid called lymph. The primary function of the lymphatic system is to transport lymph, a fluid containing white blood cells, throughout the body. Unlike the blood system, which uses a pump to circulate fluid, movements of the body drive the circulation of the lymphatic system. This is a good reason to exercise regularly. There are hundreds of lymph nodes that serve as traps for pathogens, cancer cells and toxins to facilitate their removal. Thus, swollen lymph nodes may be indicative of an infection or a tumor. Those caused by infections come and go as we become ill and recover. Those caused by cancers are likely to persist.
Impairment of cardiovascular functions
Ramar Sabapathi Vinayagam in Integrated Evaluation of Disability, 2019
The lymphatic system transmits lymphatic fluid (23). The function of the lymphatic system is to return the fluid, proteins, and immune cells from the interstitial space into intravascular space. Dysfunction of the lymphatic vessels results in accumulation of protein-rich fluid in the interstitial space. The collection of protein-rich fluid in the interstitial space, that is, lymphedema, may be due to congenital or acquired causes. Primary lymphedema is due to congenital absence or anomaly of the lymph node or vessels, for example, Milroy’s disease. Secondary lymphedema is due to infections, such as filarial infection, malignancy per se, removal of lymph glands for the treatment of cancer, and radiotherapy. Secondary lymphedema may be attributable to the sequel of treatment for cancer, such as breast cancer, soft tissue sarcoma, gynecologic malignancy, and melanoma (24,25). Lymphedema may result in disfigurement, impairment of mobility of a joint, limitation of activities, and restriction of participation. Integrated Evaluation of Disability defines impairment based on parameters, namely lymphedema, disfigurement, limitation of ROM joint, and sequels such as infections, sarcoidosis, lymphangiosarcoma, and amputations (Illustration 9.5 and Table 9.7).
Lymphatic targeting for therapeutic application using nanoparticulate systems
Published in Journal of Drug Targeting, 2022
Nidhi Singh, Mayank Handa, Vanshikha Singh, Prashant Kesharwani, Rahul Shukla
The lymphatic system was first recognised by Gasparo Aselli in the seventeenth century as per ancient text reports. It was later in the eighteenth century when various aspects of lymphatic system including its anatomy, got its attention and significance. Vascular system is further compartmentalised into lymphatic system that encompass different convoluted web of channels and hold a clear liquid termed lymph. Lymphatic system is composed of lymphatic duct, lymphatic capillaries, lymphatic vessel and some lymphatic organs including spleen and lymph node. Lymphatic vessels carry a clear watery fluid lymph, and white blood cells. Furthermore, lymphatic system is widely distributed in other parts of body in the form of lymph nodes, which is present in the neck, chest, armpit, groyne, abdomen. Lymphatic system maintains homeostasis and protection of the body tissues against different bacterial and viral infection by the mechanism of filtration. The lymphatic system not only filters the elements from lymph but avoid the first-pass hepatic metabolism of drugs directly via intestinal uptake [1]. This property plays an important role in tissue defense against infections by promoting the lymphocytic activity which in turn provides immunity or resistance. As mentioned, one of the major roles of the lymphatic system is to maintain water homeostasis in the body by recurring fluids present outside the body and oozing out into the blood circulation. It also enhances the absorption of antibiotics, water-insoluble vitamins, long-chain fatty acid and cholesterol ester.
The tumor microenvironment and triple-negative breast cancer aggressiveness: shedding light on mechanisms and targeting
Published in Expert Opinion on Therapeutic Targets, 2022
Natsuki Furukawa, Vered Stearns, Cesar A. Santa-Maria, Aleksander S. Popel
The physiological roles of the lymphatic system are to collect interstitial fluid from tissues, absorb lipids from the digestive system, and immune surveillance. In the TME, cancer cells release growth factors and cytokines such as VEGF-C to induce lymphangiogenesis. As a result, TNBC cells may invade these lymphatic vessels, migrate to the lymph node, and eventually exit the lymphatic system to enter the venous system. Disseminated TNBC cells may reach and metastasize to organs such as lung, bone, liver, and brain via the circulatory system [144]. During the invasion process, cancer cells remodel the lymphatic endothelial cells to facilitate invasion. Lee et al. demonstrated that TNBC cells induced expression of CCL5 from lymphatic endothelial cells. CCL5 recruited CCR5-positive TNBC cells to lymphatic vessels and facilitated invasion of the lymph nodes [145]. Other chemokine signaling pathways known to recruit TNBC cells to the lymphatic vessel are CCL21/CCR7, CXCL12/CXCR4, and CCL27/CCR10 [146].
Clinical and immunologic differences in cellulitis vs. pseudocellulitis
Published in Expert Review of Clinical Immunology, 2021
Michael Goldenberg, Henry Wang, Trent Walker, Benjamin H Kaffenberger
Lymphedema is a high-protein edema that results from lymphatic insufficiency [42]. Lymphedema can be related to cancer, filariasis [8], anatomic abnormalities and obesity, or genetic disorders [43]. When functioning properly, the lymphatic system channels extracellular fluid and large molecules to lymph nodes where immune surveillance can occur before draining fluid to the vascular system. When this transport is impeded, the excess proteins remain in the subcutaneous tissue [42], osmotically drawing fluids into the area, creating dermal edema [44] and increasing risk for infection [42]. The impaired lymphatic return also contributes to microtears in connective tissue, triggering an influx of neutrophils [44]. Decreased tissue perfusion results in tissue hypoxia, resulting in upregulation of hypoxia-inducible factor 1 alpha (HIF-1a) and downregulation of hypoxia-inducible factor 2 alpha (HIF-2a) in lymphatic endothelial cells [45]. One study showed that HIF-2a is an important mediator for proper lymphatic function and suggests that restoring HIF-2a via adenovirus mediated gene therapy could reduce chronic morbidity related to lymphedema [45]. The poor tissue perfusion also contributes to build up of toxins within subcutaneous tissues, leading to an inflammatory infiltrate with systemic leukocytosis (figure 3) [44].