Blood IL-6 level correlates with Depression Scores

Major depressive disorder (MDD) is a leading psychiatric illness across the world. Around 30-60% of patients with depression do not respond to available anti-depressive treatments. The proinflammatory cytokine IL-6 has a crucial role in the development of MDD. IL-6 is consistently increased in blood samples of MDD patients. Blood IL-6 level correlates with depression scores. Inhibiting IL-6 could offer a new approach in treating depression.

Check out our sensitive IL-6 ELISA kit for clinical serum and plasma samples.

 √  Full VALIDATION package
√  EASY – ready to use calibrators & controls included
√  Automatable
√  HIGH QUALITY GUARANTEED

Blood IL-6 level correlates with Depression Scores 

Role of Interleukin-6 in Depressive Disorder. Int J Mol Sci. 2020 Mar 22;21(6):2194. doi: 10.3390/ijms21062194. PMID: 32235786; PMCID: PMC7139933.

Ting EY et al., J. Int J Mol Sci. 2020 Mar 22;21(6):2194. doi: 10.3390/ijms21062194. PMID: 32235786. Full text link

Abstract link

Major depressive disorder (MDD), which is a leading psychiatric illness across the world, severely affects quality of life and causes an increased incidence of suicide. Evidence from animal as well as clinical studies have indicated that increased peripheral or central cytokine interleukin-6 (IL-6) levels play an important role in stress reaction and depressive disorder, especially physical disorders comorbid with depression. Increased release of IL-6 in MDD has been found to be a factor associated with MDD prognosis and therapeutic response, and may affect a wide range of depressive symptomatology. However, study results of the IL6 genetic effects in MDD are controversial. Increased IL-6 activity may cause depression through activation of hypothalamic-pituitary-adrenal axis or influence of the neurotransmitter metabolism. The important role of neuroinflammation in MDD pathogenesis has created a new perspective that the combining of blood IL-6 and other depression-related cytokine levels may help to classify MDD biological subtypes, which may allow physicians to identify the optimal treatment for MDD patients. To modulate the IL-6 activity by IL-6-related agents, current antidepressive agents, herb medication, pre-/probiotics or non-pharmacological interventions may hold great promise for the MDD patients with inflammatory features.

Related ELISA kits

VEGF ELISA – BI-VEGF – Product link

Angiopoietin-2 ELISA – BI-ANG2 – Product link

Neuropilin-1 ELISA – BI-20409 – Product link

Semaphorin 4D ELISA – BI-20405 – Product link

 Related publications

 On inflammatory hypothesis of depression: what is the role of IL-6 in the middle of the chaos?

Roohi E et al., J Neuroinflammation. 2021 Feb 16;18(1):45. doi: 10.1186/s12974-021-02100-7. PMID: 33593388; PMCID: PMC7884972. Abstract link

Abstract

Many patients with major depressive disorder (MDD) are reported to have higher levels of multiple inflammatory cytokines including interleukin 6 (IL-6). Recent studies both pre-clinical and clinical have advocated for the functional role of IL-6 in development of MDD and suggested a great potential for targeting this cytokine to open new avenues in pharmacotherapy of depression. The purpose of the present narrative review was to provide an integrated account of how IL-6 may contribute to development of depression. All peer-reviewed journal articles published before July 2020 for each area discussed were searched by WOS, PubMed, MEDLINE, Scopus, Google Scholar, for original research, review articles, and book chapters. Publications between 1980 and July 2020 were included. Alterations in IL-6 levels, both within the periphery and the brain, most probably contribute to depression symptomatology in numerous ways. As IL-6 acts on multiple differing target tissues throughout the body, dysregulation of this particular cytokine can precipitate a multitude of events relevant to depression and blocking its effects can prevent further escalation of inflammatory responses, and potentially pave the way for opening new avenues in diagnosis, treatment, and prevention of this debilitating disorder.

The IL-6 antagonist tocilizumab is associated with worse depression and related symptoms in the medically ill.

Knight JM et al., Transl Psychiatry. 2021 Jan 18;11(1):58. doi: 10.1038/s41398-020-01164-y. PMID: 33462203; PMCID: PMC7812704. Abstract link

 Abstract

Because medical illness is associated with increased inflammation and an increased risk for treatment-resistant major depressive disorder, anti-cytokine therapy may represent a novel, and especially efficacious, treatment for depression. We hypothesized that blockade of the interleukin (IL)-6 signaling pathway with tocilizumab would decrease depression and related symptomatology in a longitudinal cohort of allogeneic hematopoietic stem cell transplantation (HCT) patients, a medically ill population with a significant inflammation and psychopathology. Patients undergoing allogeneic HCT received either a single dose of tocilizumab one day prior to HCT (n = 25), or HCT alone (n = 62). The primary outcome included depressive symptoms at 28 days post HCT; anxiety, fatigue, sleep, and pain were assessed at pretreatment baseline and days +28, +100, and +180 post HCT as secondary outcomes. Multivariate regression demonstrated that preemptive treatment with tocilizumab was associated with significantly higher depression scores at D28 vs. the comparison group (β = 5.74; 95% CI 0.75, 10.73; P = 0.03). Even after adjustment for baseline depressive symptoms, propensity score, and presence of acute graft-versus-host disease (grades II-IV) and other baseline covariates, the tocilizumab-exposed group continued to have significantly higher depression scores compared to the nonexposed group at D28 (β = 4.73; 95% CI 0.64, 8.81; P = 0.02). Despite evidence that IL-6 antagonism would be beneficial, blockade of the IL-6 receptor with tocilizumab among medically ill patients resulted in significantly more-not less-depressive symptoms.