What is IL-6?

Interleukin-6(IL-6), is a broadly functional and pleiotropic cellular inflammatory factor that belongs to the interleukin family. IL-6 is a small-molecule glycoprotein with a molecular weight of 19-28 kDa and consists of 184 amino acids that form four α-helices, and usually exists as a monomer, which is produced by fibroblasts, monocytes, T lymphocytes, B lymphocytes, epithelial cells, keratinocytes, and a variety of tumour cells. It is produced by fibroblasts, monocytes/macrophages, T-lymphocytes, B-lymphocytes, epithelial cells, keratinocytes, and various tumour cells.

IL-6 is an important cytokine expressed by the intrinsic immune system in the initial response to injury and infection and promotes hepatic production of acute phase reactants (e.g., CRP, C3, Fbg, TPO, SAA, Hepc, etc.) as well as stimulation and alteration of bone marrow cells to produce more polymorphonuclear leukocytes.

IL-6 also plays an important role in the acquired immune response by stimulating antibody production and inducing the differentiation of naïve CD4+ T cells into IL-6 also plays an important role in the acquired immune response by stimulating antibody production and inducing the differentiation of naïve CD4+ T cells into effector T cells. In addition, IL-6 promotes the differentiation or proliferation of several non-immune cells.

Clinical application of IL-6

IL-6 is rapidly produced during acute inflammatory reactions following internal and external injuries, surgery, stress reactions, infections, brain death, and other conditions. IL-6 concentrations in surgical patients are significantly associated with surgical trauma. Continuous measurement of IL-6 levels in serum or plasma of patients in intensive care units can effectively assess the severity of systemic inflammatory response syndrome (SIRS).

Specific clinical applications of IL-6 are shown below:

① Indicators of early infection：IL-6 precedes CRP and PCT in the inflammatory response(IL-6 levels increase rapidly after bacterial infection, reaching a peak at 2h) and is an important marker of early inflammation, both for sepsis, neonatal sepsis and respiratory infections, and early postoperative infections.

② Serum levels of interleukin-6 are often high in patients with rheumatoid arthritis, psoriasis and systemic lupus erythematosus; IL-6 can also be used as a marker for rheumatic co-infections to determine the presence of co-infections.

③ IL-6 promotes tumour growth, angiogenesis and metastasis and reduces anti-tumour immune responses.Therefore, it is also considered as one of the tumour biomarkers.

④ IL-6 is valuable in identifying Gram-negative and positive bacterial infections.

⑤ IL-6 can be used to evaluate the severity of infection and determine the prognosis. When IL-6 is >1000 μg/mL, it indicates a poor prognosis, and dynamic observation of IL-6 levels can also help to understand the progression of infectious diseases and the response to treatment.

Factors affecting IL-6

Although the rise in IL-6 levels is mainly caused by early infectious diseases, there may be other reasons for high IL-6 levels, the main causes of which are shown below:

Infectious Diseases

(Pneumonia, Bronchitis, Meningitis, Septicaemia caused by viruses, bacteria, fungi)

Oncological Disease

(Liver cancer, lung cancer, stomach cancer, pancreatic cancer, lymphoma and other malignant tumour diseases)

Skin Lesion

(Skin burns that cause localised redness, swelling and pain)

Rheumatoid Arthritis

(Inflammatory reaction at the joint site)

Systemic Lupus Erythematosus

Summary

IL-6 is found to be elevated earlier than conventional inflammatory markers (CRP, PCT), so its significance in the early stage of infection is greater than that of other tests, and IL-6 can be used to evaluate the severity of infection and determine the prognosis, which helps to understand the progress of infectious diseases and the response to treatment, and therefore needs to be taken seriously.

The ReLIA IL-6 Immunoassay is CE-marked cleared. For more details on ReLIA IL-6 Immunoassay products and prices please contact us at  marketing@ReLIAchina.com

References

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