Changes of the cytokine profile in inflammatory bowel diseases

Table 1 The disease-related immunological and pathological effects of cytokines

		Ulcerative colitis	Crohn's disease
Interleukin-1 family	IL-1	Inflammation induction
	IL-18	NI	Mucosal T cell IL-10 secretion ↓
			Th1 response ↑
	IL-33	Reconstitute mucosal barrier defence	NI
		Epithelial mucus secretion ↑
		Th2-response ↑
		Wound healing and angiogenesis ↑
Tumor necrosis factor superfamily	TNF-α	Adhesion molecules expression ↑	Initiates pro-inflammatory signaling
		Fibroblast proliferation ↑
		Procoagulant factors level ↑
		Initiation of cytotoxic, apoptotic, and acute-phase responses
		IL-1β, IL-6, IL-33 production ↑
		Modulates epithelial cell ST2 expression
	TL1A	IFN-γ secretion ↑	IFN-γ, IL-17 production ↑
		Modulates epithelial cell apoptosis	Th17 differentiation ↑
	LIGHT	NI	Mediates Th1 response and mucosa specific inflammation
Interleukin-6 family	IL-6	Involved in colitis-associated carcinogenesis	Mediates T cell resistance to apoptosis
		Possible role in extraintestinal manifestations	Influences of disease relapse
Interleukin-8	IL-8	Mediates the activation and migration of neutrophils	NI
Interleukin-12 family	IL-12	Modulates macrophage activity	Early induction of Th1 polarization of naïve T cells
			IFN-γ of the mucosal T cells
	IL-23	Promotes Th17 cell differentiation	IL-17 and IL-6 mediated intestinal inflammation
		Controlling Th17 response
		Influences Treg cell development
		Number of mucosal Treg cells ↓
	IL-27		Proliferation of naïve CD4+ T cells ↑
			IFN-γ production ↑
	IL-35	Possible controlling of T-cell dependent inflammation	NI
Interleukin-13	IL-13	Induces cellular cytotoxicity against colonic epithelium	NI
		Epithelial cell apoptosis ↑
		Tight junction integrity ↓
		Epithelial restitution velocity ↓
		Colonic wall fibrosis ↑
Interleukin 17 family	IL-17	Pro- and anti-inflammatory effects	IL-17, IL-22, IFN-γ production ↑
			Enhance T cell recruitment into the lamina propria
	IL-25	Possible inhibition of IL-12 secretion	NI
		Possible promotion of Th1-driven inflammation
Interleukin-21	IL-21	Maintainer of Th1-mediated inflammation	Required for IL-17A and IFN-γ production
		Inhibits Treg cell differentiation	Fibroblasts MMP secretion ↑
		CD4+ T cell resistance to Treg-suppression ↑
Interleukin-5	IL-5	Activates eosinophil function and migration	NI
Interleukin-10 family	IL-10	Inhibits antigen presentation	Constrains Th17 cell development
		Pro-inflammatory cytokine release ↓
	IL-19	TNF-α, IL-6, IL-12 secretion ↓	NI
	IL-22	Goblet cell hyperplasia ↑	Promotes mucosal healing
		Mucus production ↑
Interleukin-4	IL-4	TNF-α, IL-1 production ↓	NI
		Humoral immune response ↑
		Mucosal healing ↑
		Monocyte/macrophage VEGF production ↓
Transforming growth factor-β	TGF-β	Possible suppression of IL-33 production	Collagen synthesis ↑
			Regulates the balance between matrix-degrading MMPs and their inhibitors
			IL-13 expression ↑
			EMT ↑

IL: Interleukin; TNF: Tumor necrosis factor; IFN: Interferon; TL1A: TNF-like factor; TGF-β: Transforming growth factor-β; LIGHT: Lymphotoxins, exhibits inducible expression, and competes with herpes simplex virus glycoprotein D for herpesvirus entry mediator, a receptor expressed by T lymphocytes; MMP: Matrix metalloproteinase; VEGF: Vascular-endothelial growth factor; EMT: Epithelial-to-mesenchymal transition; NI: (possibly) Not invloved in pathogenesis.