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Review
. 2021 Jun;93(6):3915-3924.
doi: 10.1002/jmv.26654. Epub 2020 Nov 22.

Defining IL-6 levels in healthy individuals: A meta-analysis

Elias A Said  1 , Iman Al-Reesi  2 , Nawal Al-Shizawi  2 , Sanjay Jaju  3 , Mohammed S Al-Balushi  1 , Crystal Y Koh  1 , Ali A Al-Jabri  1 , Lakshmanan Jeyaseelan  4
Affiliations
Review

Defining IL-6 levels in healthy individuals: A meta-analysis

Elias A Said et al. J Med Virol. 2021 Jun.

Abstract

Background: Interleukin-6 (IL-6) is produced by and impacts different cell types in human. IL-6 is associated with different diseases and viral infections, including COVID-19. To our knowledge, no normal values were reported for IL-6 in the blood of healthy individuals. We have reviewed and performed a meta-analysis on a total of 140 studies, including 12,421 values for IL-6 in the blood of healthy adult donors. Among these studies, 83 did not report a mean value and the standard deviation. Therefore, for the statistical analysis, we used the values reported in 57 studies, which included 3166 values for IL-6.

Results: The reported values for IL-6 in the blood of healthy donors varied between 0 and 43.5 pg/ml. The pooled estimate of IL-6 was 5.186 pg/ml (95% confidence interval [CI]: 4.631, 5.740). As the age increased by 1 year, IL-6 values increased by 0.05 pg/ml (95% CI: 0.02, 0.09; p < .01). Though the heterogenicity, as determined by I2 statistics, was high in our study, the differences in IL-6 values are still at the level of a few pg/ml, which might be related to the differences in the conditions that influence IL-6 production in the healthy population.

Conclusions: This is the first meta-analysis reporting the levels of IL-6 in the blood of healthy donors based on a large number of studies and donors. Therefore the 95% CI values determined in our study could well serve as a reference range for quick decision-making in clinical interventions, particularly those aiming to inhibit IL-6, especially urgent interventions, for example, COVID-19.

Keywords: IL-6; blood; healthy; human; levels.

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References

REFERENCES

    1. Naka T, Nishimoto N, Kishimoto T. The paradigm of IL-6: from basic science to medicine. Arthritis Res. 2002;4(Suppl 3):S233-S242.
    1. Puel A, Casanova JL. The nature of human IL-6. J Exp Med. 2019;216(9):1969-1971.
    1. Kaur S, Bansal Y, Kumar R, Bansal G. A panoramic review of IL-6: structure, pathophysiological roles and inhibitors. Bioorg Med Chem. 2020;28(5):115327.
    1. Velazquez-Salinas L, Verdugo-Rodriguez A, Rodriguez LL, Borca MV. The role of interleukin 6 during viral infections. Front Microbiol. 2019;10:1057.
    1. Chhetri S, Khamis F, Pandak N, Al-Khalili H, Said E, Petersend E. A fatal case of COVID-19 due to metabolic acidosis following dysregulate inflammatory response (cytokine storm). IDCases. 2020;21: e00829.

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