. 2024 Sep 7;17:6113–6141. doi: 10.2147/JIR.S385825

Table 1.

Studies Measuring Peripheral IL-6 or TNF-α in Association with Depression or Anxiety in Alzheimer’s Disease. Number of Asterisks Denote Significance Level (* P<0.05, ** P<0.01, *** P<0.001)

Assay Source	Authors	Participants	Study Design	Scale	Inflammatory Marker	Results
Serum	Banerjee et al, 2017⁸⁹	AD (34 with depression, 26 without depression) HC = 60	Cross sectional case control	DSM-IV	IL-6 and TNF-α	IL-6 increased with AD with depression compared to AD without depression* TNF-α increased in AD with depression compared to AD without depression IL-6 (r = −0.472 and TNFα r = −0.651* negative correlations with MMSE in AD with depression but no correlations in AD without depression.
Serum	Gorska-Ciebiada et al, 2015¹¹⁸	MCI = 62 (25 with depression), HC = 132 (57 with depression)	Cross sectional case control	GDS	CRP, IL-6, TNF-α	GDS-30 correlated with CRP (0.56*) and TNF-α (0.77) in MCI with depression group. Multivariate logistic regression revealed IL-6* among other factors (CVD, poor glycaemic control) increased likelihood of having MCI in depressed patients.
Serum	Khemka et al, 2014¹¹⁶	AD = 55 (31 with depression and 24 without depression), HC = 37	Cross sectional case control	DSV-IV criteria	IL-1-β, IL-6, TNFα	IL-6 and TNFα were higher in AD with depression compared HC and AD without depression*. Increased IL-1β in both groups of AD patients compared to controls*
Serum	Johnson et al, 2016¹¹⁵	AD = 107	Cross sectional study	GDS	Inflammatory marker panel (details not described)	7 proteins showed significantly higher risk of depression: MIP1, IL-6 , VCAM1, Adiponectin, Factor VII *, IL-5 , ICAM1*
Serum and Plasma	Alvarez et al, 1996¹²⁰	AD = 20	Cross sectional cohort	HRSD	Histamine, IL1-β, TNF-a	Negative correlation between histamine and HRSD (−0.63**)
Serum	Holmes et al, 2011⁸⁶	AD = 275	Longitudinal cohort study	NPI	CRP, TNF-α, IL-6	Patients with low TNF-α had lower NPI scores over 6 months*. Increased TNF-α was associated with more frequent symptoms of agitation, depression, anxiety. Lower IL-6 was associated with lower NPI scores over period of 6 months. Increased IL-6 associated with increased frequency of hallucinations and apathy*.
Serum	Hall et al, 2012¹¹⁷	AD = 91, HC = 161	Cross sectional case control	GDS	IL-6, IL-10, IL-1, CRP, TNF-α and MIF	TNF accounted for 12% variance in apathy score in men. MIF weak predictor R2 < 0.03* of total GDS score and 3/4 symptom clusters in all participants. MIF predictor of depression in men with AD accounting for 12% of the variance in apathy sore, and 15–51% of the variance in 3 symptom clusters. In females, MIF, ICAM and CRP accounted for 26% variance in apathy.