Septic shock is a potentially fatal medical condition that occurs when sepsis, which is organ injury or damage in response to infection, leads to dangerously low blood pressure and abnormalities in cellular metabolism. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) defines septic shock as a subset of sepsis in which particularly profound circulatory, cellular, and metabolic abnormalities are associated with a greater risk of mortality than with sepsis alone. Patients with septic shock can be clinically identified by requiring a vasopressor to maintain a mean arterial pressure of 65 mm Hg or greater and having serum lactate level greater than 2 mmol/L (>18 mg/dL) in the absence of hypovolemia. This combination is associated with hospital mortality rates greater than 40%.
Interleukin-2 (IL-2) is an interleukin, a type of cytokine signaling molecule in the immune system. It is a 15.5–16 kDa protein that regulates the activities of white blood cells (leukocytes, often lymphocytes) that are responsible for immunity. IL-2 is part of the body's natural response to microbial infection, and in discriminating between foreign ("non-self") and "self". IL-2 mediates its effects by binding to IL-2 receptors, which are expressed by lymphocytes. The major sources of IL-2 are activated CD4+ T cells and activated CD8+ T cells.
Interleukin 6 (IL-6) is an interleukin that acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine. In humans, it is encoded by the IL6 gene.
Interleukin 12 (IL-12) is an interleukin that is naturally produced by dendritic cells, macrophages, neutrophils, and human B-lymphoblastoid cells (NC-37) in response to antigenic stimulation. IL-12 belongs to the family of interleukin-12. IL-12 family is unique in comprising the only heterodimeric cytokines, which includes IL-12, IL-23, IL-27 and IL-35. Despite sharing many structural features and molecular partners, they mediate surprisingly diverse functional effects.
Interleukin 7 (IL-7) is a protein that in humans is encoded by the IL7 gene.
IRAK-4, in the IRAK family, is a protein kinase involved in signaling innate immune responses from Toll-like receptors. It also supports signaling from T-cell receptors. IRAK4 contains domain structures which are similar to those of IRAK1, IRAK2, IRAKM and Pelle. IRAK4 is unique compared to IRAK1, IRAK2 and IRAKM in that it functions upstream of the other IRAKs, but is more similar to Pelle in this trait. IRAK4 has important clinical applications.
Interleukin-1 beta (IL-1β) also known as leukocytic pyrogen, leukocytic endogenous mediator, mononuclear cell factor, lymphocyte activating factor and other names, is a cytokine protein that in humans is encoded by the IL1B gene. There are two genes for interleukin-1 (IL-1): IL-1 alpha and IL-1 beta. IL-1β precursor is cleaved by cytosolic caspase 1 to form mature IL-1β.
Myeloid differentiation primary response 88 (MYD88) is a protein that, in humans, is encoded by the MYD88 gene.
Mevalonate kinase deficiency (MKD) is an autosomal recessive metabolic disorder that disrupts the biosynthesis of cholesterol and isoprenoids. It is a very rare genetic disease.
Interleukin-15 (IL-15) is a protein that in humans is encoded by the IL15 gene. IL-15 is an inflammatory cytokine with structural similarity to Interleukin-2 (IL-2). Like IL-2, IL-15 binds to and signals through a complex composed of IL-2/IL-15 receptor beta chain (CD122) and the common gamma chain. IL-15 is secreted by mononuclear phagocytes following infection by virus(es). This cytokine induces the proliferation of natural killer cells, i.e. cells of the innate immune system whose principal role is to kill virally infected cells.
Tocilizumab, sold under the brand name Actemra among others, is an immunosuppressive drug, used for the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis, a severe form of arthritis in children, and COVID‑19. It is a humanized monoclonal antibody against the interleukin-6 receptor (IL-6R). Interleukin 6 (IL-6) is a cytokine that plays an important role in immune response and is implicated in the pathogenesis of many diseases, such as autoimmune diseases, multiple myeloma and prostate cancer. Tocilizumab was jointly developed by Osaka University and Chugai, and was licensed in 2003 by Hoffmann-La Roche.
Signal transducer and activator of transcription 1 (STAT1) is a transcription factor which in humans is encoded by the STAT1 gene. It is a member of the STAT protein family.
Canakinumab (INN), sold under the brand name Ilaris, is a medication for the treatment of systemic juvenile idiopathic arthritis (SJIA) and active Still's disease, including adult-onset Still's disease (AOSD). It is a human monoclonal antibody targeted at interleukin-1 beta. It has no cross-reactivity with other members of the interleukin-1 family, including interleukin-1 alpha.
Interleukin-12 receptor, beta 1, or IL-12Rβ1 in short, is a subunit of the interleukin 12 receptor. IL12RB1, is the name of its human gene. IL-12Rβ1 is also known as CD212.
Interleukin-2 receptor alpha chain is the human protein encoded by the IL2RA gene.
Interleukin-17 receptor (IL-17R) is a cytokine receptor which belongs to new subfamily of receptors binding proinflammatory cytokine interleukin 17A, a member of IL-17 family ligands produced by T helper 17 cells (Th17). IL-17R family consists of 5 members: IL-17RA, IL-17RB, IL-17RC, IL-17RD and IL-17RE. Functional IL-17R is a transmembrane receptor complex usually consisting of one IL-17RA, which is a founding member of the family, and second other family subunit, thus forming heteromeric receptor binding different ligands. IL-17A, a founding member of IL-17 ligand family binds to heteromeric IL-17RA/RC receptor complex. IL-17RB binds preferentially IL-17B and IL-17E and heteromeric IL-17RA/RE complex binds IL-17C. However, there is still unknown ligand for IL-17RD. The first identified member IL-17RA is located on human chromosome 22, whereas other subunits IL-17RB to IL-17RD are encoded within human chromosome 3.
Siltuximab is a chimeric monoclonal antibody. It binds to interleukin-6. Siltuximab has been investigated for the treatment of neoplastic diseases: metastatic renal cell cancer, prostate cancer, other types of cancer, and for Castleman's disease.
The Interleukin-1 family is a group of 11 cytokines that plays a central role in the regulation of immune and inflammatory responses to infections or sterile insults.
Trained immunity is a long-term functional modification of cells in the innate immune system which leads to an altered response to a second unrelated challenge. For example, the BCG vaccine leads to a reduction in childhood mortality caused by unrelated infectious agents. The term "innate immune memory" is sometimes used as a synonym for the term trained immunity which was first coined by Mihai Netea in 2011. The term "trained immunity" is relatively new – immunological memory has previously been considered only as a part of adaptive immunity – and refers only to changes in innate immune memory of vertebrates. This type of immunity is thought to be largely mediated by epigenetic modifications. The changes to the innate immune response may last up to several months, in contrast to the classical immunological memory, and is usually unspecific because there is no production of specific antibodies/receptors. Trained immunity has been suggested to possess a transgenerational effect, for example the children of mothers who had also received vaccination against BCG had a lower mortality rate than children of unvaccinated mothers. The BRACE trial is currently assessing if BCG vaccination can reduce the impact of COVID-19 in healthcare workers. Other vaccines are also thought to induce immune training such as the DTPw vaccine.
Mihai G. Netea is a Romanian Dutch physician and professor at Radboud University Nijmegen, specialized in infectious disease, immunology, and global health.
