Hematopoietic growth factor, activation of basophils and eosinophils
Role in allergic diseases for example, AD, different types of cancers, lymphocytic and acute myeloid leukemias
IL-6
Homodimer
19–26 kd
IL-6R, (sIL-6R) gp130
Hepatocytes, leukocytes, T cells, B cells, hemopoietic cells
Liver: synthesis of acute phase proteins; leukocytes: trafficking, activation; T cell: differentiation, activation, survival; B cell: differentiation, production of IgG, IgM, IgA hematopoiesis
Autoimmune disease, chronic inflammatory diseases for example, AD, B-cell malignancy, SLE, Castleman’s disease, plasmacytoma/multiple myeloma
IL-7
Monomer
25 kd
IL-7R and sIL-7R
B, T, and NK cells
Proliferation of pre-B and pro-B cells (mice), megakaryocytes maturation, VDJ recombinations, naive T-cell survival, synthesis induction of inflammatory mediators in monocytes
Allergy/autoimmunity and psoriasis
IL-8 (CXCL8)
Homodimer
16 kd
CXCR1 and CXCR2
Neutrophils, NK cells, T cells, basophils, eosinophils, endothelial cells
Chemoattractant for neutrophils, NK cells, T cells, basophils, eosinophils; mobilization of hematopoieticstem cells; angiogenesis
Increased levels during inflammatory diseases (e.g., AD, RA, psoriasis, bacterial and viral infections)
Macrophages, monocytes, T cells, B cells, NK cells, mast cells, DC and granulocytes
Immune suppression
Cancer, autoimmunity, allergy (e.g., AD)
IL-12 (p35/p40)
Heterodimer
IL-12a p35, 35 kd; IL12b p40, 40 kd
IL-12Rb1 and IL-12Rb2
T cells (Th1 cells), NK cells
Induce Th1-cell differentiation and cytotoxicity
Chronic inflammation (e.g., AD), impaired Th1 response with higher susceptibility to intracellular pathogens, use as anticancer agent
IL-15
Monomer
14-15 kd
IL-15R
T, NK, and NKT cells T-cell activation
Proliferation and activation of NK cells, differentiation of T cells, suppression of IL-2 induced AICD of T cells, homeostasis of CD8+ memory, NK and NKT cells, enhancement of Th2 differentiation and suppression of allergic rhinitis
Autoimmune and inflammatory diseases
IL-16
Homotetramer
56 kd
CD4
T cells, monocytes, macrophages, eosinophils
Chemotaxis, modulation of T-cell response
Increased during various inflammatory and infectious diseases including atopic eczema, allergic asthma, Crohn’s disease, RA, hepatitis C infection, tuberculosis; inhibits HIV infection
IL-18
Heterodimer
22.3 kd
IL-18R
Variety of cells, T cells, NK cells, macrophages, epithelial cells, chondrocytes
Induction of IFN-γ in presence of IL-12, enhances NK cell cytotoxicity, promoting Th1 or Th2-cell responses depending cytokine milieu
Autoimmune diseases or inflammatory disorders, AD, RA, psoriasis, MS, type I diabetes
IL-19
Monomer
20.5 kd predicted size of precursor; 17 kd, predicted size of mature protein; 35–40 kd, found in transfected cells, glycosylated
IL20R1/IL-20R2
Keratinocytes
Unknown
Psoriasis
IL-20
Monomer
20 kd predicted size of precursor; 17.5 kd, predicted size of mature protein
IL-20R1/IL-20R2 and IL-22R1/IL-20R2
Keratinocytes, monocytes
Role in skin biology
Psoriasis, RA, atherosclerosis
IL-23 (p191p40)
Heterodimer
IL-12b p40, 40 kd; IL-23 p19, 19 kd
IL-12Rb1 and IL-23R
T cells (TH17 cells) and macrophages
Stimulate production of proinflammatory IL-17 and promote memory T-cell proliferation
Susceptibility to extracellular pathogens, exacerbate organ specific autoimmune inflammation, chronic inflammatory diseases (psoriasis, AD)
IL-24
Homodimer and monomer
23.8 kd, predicted size of unprocessed precursor; 18 kd, unglycosylated mature protein; 35 kd, observed size of secreted IL-24, glycosylated
IL20R1/IL-20R2 and IL-22R1/IL-20R2
Keratinocytes, cancer cells
Tumor suppression
Melanoma, psoriasis
IL-27 (p281EBI3)
Heterodimer
IL-27a p28, 28 kd; IL-27b EBI3, 25.4 kd
WSX-1 and gp130
T cells, NK cells
Induction of Tbet promoting Th1-cell differentiation, inhibition of Th17-cell response via STAT1
Immune pathology because of uncontrolled inflammatory response: for example, in psoriasis or in epidermal compartment of patients with eczema
IL-32
Unknown
14.9–26.6 kd
Unknown
Macrophages, DCs, T cells, PBMCs, monocytes
Induction of TNF-α, IL-8, and IL-6, apoptosis
AD, RA, IBD, autoimmune disease
IL-37
Unknown
17–24 kd
IL-18Ra?
Intracellular mechanism manner and DC
Suppression of proinflammatory cytokines and inhibition of DC activation
RA
TNF-α
Homotrimer
26 kd transmembrane and a 17 kd secreted form
TNF-R1 and TNF-R2
Both receptors are virtually on all cell types except for the red blood cells, but TNFR1 is more ubiquitous, and TNFR2 is often more abundant on endothelial cells and cells of hematopoietic lineage
Regulation of immune cells: induce fever, apoptotic cell death, (through IL-1 and L-6 production, inhibit tumorigenesis and viral replication, recruiting macrophage and neutrophils to a site of infection
Chronic inflammation (AD, psoriasis, RA, IBD, COPD), Alzheimer's disease, cancer
