Immunostimulants, also known as immunostimulators, are substances (drugs and nutrients) that stimulate the immune system usually in a non-specific manner by inducing activation or increasing activity of any of its components. One notable example is the granulocyte macrophage colony-stimulating factor. The goal of this stimulated immune response is usually to help the body have a stronger immune system response in order to improve outcomes in the case of an infection or cancer malignancy. There is also some evidence that immunostimulants may be useful to help decrease severe acute illness related to chronic obstructive pulmonary disease or acute infections in the lungs.
There are two main categories of immunostimulants: [1]
Many endogenous substances are non-specific immunostimulators. For example, female sex hormones are known to stimulate both adaptive [2] and innate immune responses. [3] [4] [5] [6] Some autoimmune diseases such as lupus erythematosus strike women preferentially, and their onset often coincides with puberty. Other hormones appear to regulate the immune system as well, most notably prolactin, growth hormone and vitamin D. [7] [8]
Some publications point towards the effect of deoxycholic acid (DCA) as an immunostimulant [9] [10] [11] of the non-specific immune system, activating its main actors, the macrophages. According to these publications, a sufficient amount of DCA in the human body corresponds to a good immune reaction of the non-specific immune system.[ citation needed ]
Claims made by marketers of various products and alternative health providers, such as chiropractors, homeopaths, and acupuncturists to be able to stimulate or "boost" the immune system generally lack meaningful explanation and evidence of effectiveness. [12]
Immunostimulants have been recommended to help prevent acute illness related to chronic obstructive pulmonary disease and they are sometimes used to treat chronic bronchitis. [13] The evidence in the form of high quality clinical trials to support their use is weak, however, there is some evidence of benefit and they appear to be safe. [14] The most commonly used immunostimulant type for this purpose are bacterial-derived immunostimulants. The goal is to stimulate the person's immune system in order to prevent future infections that may result in an acute episode or exacerbation of COPD. [14]
The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism's own healthy tissue. Many species have two major subsystems of the immune system. The innate immune system provides a preconfigured response to broad groups of situations and stimuli. The adaptive immune system provides a tailored response to each stimulus by learning to recognize molecules it has previously encountered. Both use molecules and cells to perform their functions.
Immunology is a branch of biology and medicine that covers the study of immune systems in all organisms.
Inflammation is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function.
In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, Henoch–Schönlein purpura, systemic lupus erythematosus, Sjögren syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis, ankylosing spondylitis, polymyositis, dermatomyositis, and multiple sclerosis. Autoimmune diseases are very often treated with steroids.
Cytokines are a broad and loose category of small proteins important in cell signaling. Due to their size, cytokines cannot cross the lipid bilayer of cells to enter the cytoplasm and therefore typically exert their functions by interacting with specific cytokine receptors on the target cell surface. Cytokines have been shown to be involved in autocrine, paracrine and endocrine signaling as immunomodulating agents.
Macrophages are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris, and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. This process is called phagocytosis, which acts to defend the host against infection and injury.
The T helper cells (Th cells), also known as CD4+ cells or CD4-positive cells, are a type of T cell that play an important role in the adaptive immune system. They aid the activity of other immune cells by releasing cytokines. They are considered essential in B cell antibody class switching, breaking cross-tolerance in dendritic cells, in the activation and growth of cytotoxic T cells, and in maximizing bactericidal activity of phagocytes such as macrophages and neutrophils. CD4+ cells are mature Th cells that express the surface protein CD4. Genetic variation in regulatory elements expressed by CD4+ cells determines susceptibility to a broad class of autoimmune diseases.
Humoral immunity is the aspect of immunity that is mediated by macromolecules – including secreted antibodies, complement proteins, and certain antimicrobial peptides – located in extracellular fluids. Humoral immunity is named so because it involves substances found in the humors, or body fluids. It contrasts with cell-mediated immunity. Humoral immunity is also referred to as antibody-mediated immunity.
A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious organisms including bacteria and fungi, as well as other materials such as foreign objects, keratin, and suture fragments.
Cellular immunity, also known as cell-mediated immunity, is an immune response that does not rely on the production of antibodies. Rather, cell-mediated immunity is the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
Psychoneuroimmunology (PNI), also referred to as psychoendoneuroimmunology (PENI) or psychoneuroendocrinoimmunology (PNEI), is the study of the interaction between psychological processes and the nervous and immune systems of the human body. It is a subfield of psychosomatic medicine. PNI takes an interdisciplinary approach, incorporating psychology, neuroscience, immunology, physiology, genetics, pharmacology, molecular biology, psychiatry, behavioral medicine, infectious diseases, endocrinology, and rheumatology.
Hypersensitivity pneumonitis (HP) or extrinsic allergic alveolitis (EAA) is a syndrome caused by the repetitive inhalation of antigens from the environment in susceptible or sensitized people. Common antigens include molds, bacteria, bird droppings, bird feathers, agricultural dusts, bioaerosols and chemicals from paints or plastics. People affected by this type of lung inflammation (pneumonitis) are commonly exposed to the antigens by their occupations, hobbies, the environment and animals. The inhaled antigens produce a hypersensitivity immune reaction causing inflammation of the airspaces (alveoli) and small airways (bronchioles) within the lung. Hypersensitivity pneumonitis may eventually lead to interstitial lung disease.
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.
Cluster of differentiation 40, CD40 is a type I transmembrane protein found on antigen-presenting cells and is required for their activation. The binding of CD154 (CD40L) on TH cells to CD40 activates antigen presenting cells and induces a variety of downstream effects.
Stress hormones are secreted by endocrine glands to modify one's internal environment during the times of stress. By performing various functions such as mobilizing energy sources, increasing heart rate, and downregulating metabolic processes which are not immediately necessary, stress hormones promote the survival of the organism. The secretions of some hormones are also downplayed during stress. Stress hormones include, but are not limited to:
An alveolar macrophage, pulmonary macrophage, is a type of macrophage, a professional phagocyte, found in the airways and at the level of the alveoli in the lungs, but separated from their walls.
Chemokine ligand 1 (CCL1) is also known as small inducible cytokine A1 and I-309 in humans. CCL1 is a small glycoprotein that belongs to the CC chemokine family.
In immunology, an adjuvant is a substance that increases or modulates the immune response to a vaccine. The word "adjuvant" comes from the Latin word adiuvare, meaning to help or aid. "An immunologic adjuvant is defined as any substance that acts to accelerate, prolong, or enhance antigen-specific immune responses when used in combination with specific vaccine antigens."
Bird fancier's lung (BFL), also known as bird breeder's lung, is a type of hypersensitivity pneumonitis. It can cause shortness of breath, fever, dry cough, chest pain, anorexia and weight loss, fatigue, and progressive pulmonary fibrosis. It is triggered by exposure to avian proteins present in the dry dust of droppings or feathers of a variety of birds. The lungs become inflamed, with granuloma formation. It mostly affects people who work with birds or own many birds.
An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated that there are more than 80 recognized autoimmune diseases, with recent scientific evidence suggesting the existence of potentially more than 100 distinct conditions. Nearly any body part can be involved.