Full name: Interleukin-6

Aliases:1 Hepatocyte-stimulating factor, B-cell stimulatory factor 2, cytotoxic T-cell–differentiation factor, B-cell–differentiation factor, hybridoma/plasmacytoma growth factor, monocyte–granulocyte inducer type 2, and thrombopoietin

Size:1,2 19–26 kDa

Family:1,2 Main member of the IL-6 cytokine family that also includes leukemia inhibitor factor, ciliary neurotrophic factor, oncostatin M, IL-11, and cardiotrophin-1

Receptors:1,2 IL-6 receptor (membrane bound IL-6R and soluble sIL-6R) gp130

Major cellular sources:1,2 T cells, B cells, macrophages, monocytes, fibroblasts, chondrocytes, osteoblasts, mast cells, keratinocytes, and endothelial cells

Major cellular targets:2 T cells, B cells, hepatocytes, leukocytes, and hematopoietic cells

Disease states associated with:1,2 Immune diseases, inflammation, and autoimmune diseases

Major physiologic functions:

  • IL-6 is involved in B-cell differentiation and survival, T-cell proliferation, development of osteoclasts in bone resorption, synovial fibroblast proliferation, and cartilage degradation.2

  • IL-6 is responsible for acute phase proteins synthesis and neutrophil production in the bone marrow.2,3

  • IL-6 induces direct stimulation of CRP from hepatocytes and plays a significant role in rheumatoid arthritis pathogenesis.1

  • Allergen-induced IL-6 promotes type 2 and type 17 airway inflammation.2

  • Chronic psoriatic lesions may produce large amounts of IL-6 and other pro-inflammatory cytokines, which release free fatty acids, cholesterol, and triglycerides from the adipose tissue. Consequently, patients with psoriasis have increased serum concentrations of triglycerides, total cholesterol, LDL-C, and VLDL-C.4

CRP: C-reactive protein; gp130: glycoprotein 130 subunits; IL: interleukin; LDL-C: low-density lipoprotein cholesterol; sIL-6R: soluble IL-6 receptor; VLDL-C: very low–density lipoprotein cholesterol.


  • 1.

    Srirangan S, Choy EH. Ther Adv Musculoskelet Dis. 2010;2:247‐256.

  • 2.

    Akdis M, Aab A, Altunbulakli C, et al. J Allergy Clin Immunol. 2016;138:984-1010.

  • 3.

    Wright HL, Cross AL, Edwards SW, Moots RJ. Rheumatology (Oxford). 2014;53:1321-1331.

  • 4.

    Pietrzak A, Chabros P, Grywalska E, et al. Postepy Dermatol Alergol. 2020;37:41-45.