Table 1: Characteristics of monocytes/macrophages-derived cytokines.

CytokineStructureSize molecular
weight
ReceptorsCell targetsMajor functionsDisease association

IL-1α, IL-1βHeterodimer17 kdIL-1RI, IL-1RIIT cells, fibroblasts,
epithelial and
endothelial cells
Induction of
Proinflammatory
proteins, hematopoiesis,
differentiation of
Th17 cells
Wide range of autoimmune and inflammatory
diseases: AD, RA, IBD,
psoriasis

IL-3Monomer15 kdIL-3Rα + βc (CD131)Erythroid progenitors,
Granulocyte macrophages
progenitors, CD34+
progenitor cells, basophils,
eosinophils
Hematopoietic growth factor, activation of basophils and eosinophilsRole in allergic diseases for example, AD, different types of cancers, lymphocytic and acute myeloid leukemias

IL-6Homodimer19–26 kdIL-6R,
(sIL-6R) gp130
Hepatocytes, leukocytes, T cells, B cells, hemopoietic cellsLiver: synthesis of acute phase proteins; leukocytes: trafficking, activation; T cell: differentiation, activation, survival; B cell: differentiation, production of IgG, IgM, IgA hematopoiesisAutoimmune disease, chronic inflammatory
diseases for example, AD, B-cell malignancy, SLE,
Castleman’s disease, plasmacytoma/multiple myeloma

IL-7Monomer25 kdIL-7R and sIL-7RB, 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)Homodimer16 kdCXCR1 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)

IL-10Homodimer20.5 kd, predicted
size of precursor
protein; 18.6 kd,
predicted size
mature protein,
monomer
IL-10R1/IL-10R2
complex
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)
HeterodimerIL-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-15Monomer14-15 kdIL-15RT, 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 rhinitisAutoimmune and inflammatory
diseases

IL-16 Homotetramer56 kdCD4T cells, monocytes,
macrophages, eosinophils
Chemotaxis, modulation of T-cell responseIncreased during various inflammatory and infectious diseases including atopic
eczema, allergic asthma, Crohn’s disease, RA, hepatitis C infection, tuberculosis; inhibits HIV infection

IL-18Heterodimer22.3 kdIL-18RVariety 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-19Monomer20.5 kd predicted
size of precursor;
17 kd, predicted size of mature protein; 35–40 kd, found in transfected cells, glycosylated
IL20R1/IL-20R2KeratinocytesUnknownPsoriasis

IL-20Monomer20 kd predicted size of precursor; 17.5 kd, predicted size of mature proteinIL-20R1/IL-20R2 and IL-22R1/IL-20R2Keratinocytes, monocytesRole in skin biologyPsoriasis, RA, atherosclerosis

IL-23
(p191p40)
HeterodimerIL-12b p40, 40 kd; IL-23 p19, 19 kdIL-12Rb1 and IL-23RT cells (TH17 cells)
and macrophages
Stimulate production of proinflammatory IL-17 and promote memory T-cell proliferationSusceptibility to extracellular pathogens, exacerbate organ specific autoimmune inflammation, chronic inflammatory diseases (psoriasis, AD)

IL-24Homodimer and monomer23.8 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-20R2Keratinocytes, cancer cellsTumor suppressionMelanoma, psoriasis

IL-27
(p281EBI3)
HeterodimerIL-27a p28, 28 kd;
IL-27b EBI3,
25.4 kd
WSX-1 and gp130T cells, NK cellsInduction of Tbet promoting Th1-cell differentiation, inhibition of Th17-cell response via STAT1Immune pathology because of uncontrolled inflammatory response: for example, in psoriasis or in epidermal compartment of patients with eczema

IL-32
Unknown14.9–26.6 kdUnknownMacrophages, DCs, T cells, PBMCs, monocytesInduction of TNF-α,
IL-8, and IL-6, apoptosis
AD, RA, IBD, autoimmune disease

IL-37Unknown17–24 kdIL-18Ra?Intracellular mechanism manner and DCSuppression of proinflammatory cytokines and inhibition of DC activationRA

TNF-αHomotrimer26 kd transmembrane and a 17 kd secreted formTNF-R1 and TNF-R2Both 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 lineageRegulation 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 infectionChronic inflammation (AD, psoriasis, RA, IBD, COPD), Alzheimer's disease, cancer

AD: atopic dermatitis; AICD: activation-induced cell death; COPD: chronic obstructive pulmonary disease; IBD: inflammatory bowel disease; Ig: immunoglobulin; kd: kilo Dalton; NK: natural killer; RA: rheumatoid arthritis; SLE: systemic lupus erythematosus; sIL-6R: soluble interleukin-6 receptor; Th: T helper.