Can multiple biomarker and immune pathways reinforce a shared low-grade inflammatory state?

A systemic low-grade inflammatory state is not driven by a single isolated biomarker, but rather by a complex network of overlapping lipid, cytokine, cellular, and autoimmune pathways.

Lipid and Cytokine Signaling

• Fatty Acid and Resolvin Dysregulation: An elevated arachidonic acid (AA) to eicosapentaenoic acid (EPA) ratio biases enzymatic pathways away from E-series resolvins (such as RvE1) and toward pro-inflammatory PGE₂ and TXA₂. This deprives the vascular system of specialized pro-resolving mediators (SPMs) that normally act via the ChemR23 receptor to suppress platelet activation and endothelial cell adhesion.
• IL-6 Trans-Signaling: The IL-6-to-CRP axis acts as a key modulator of systemic inflammatory tone. The rs2228145 (Asp358Ala) genetic variant promotes IL-6R shedding, increasing soluble IL-6R (sIL-6R) and shifting the pathway toward endothelial gp130 trans-signaling. This trans-signaling mode impairs VE-cadherin, causing vascular barrier loss and leukocyte adhesion.

Vascular and Cellular Pathology

• Atherogenic and Stress Pathways: ApoB-containing LDL and Lp(a) accumulate subendothelially and oxidize, generating oxidized phospholipids (OxPL) that bind scavenger receptors LOX-1 and CD36. This triggers endothelial dysfunction, P-selectin upregulation, and localized platelet-monocyte recruitment. Simultaneously, neuroendocrine stress suppresses bone marrow CXCL12, mobilizing primed Ly6C^hi monocytes and neutrophils, which elevates the neutrophil-to-lymphocyte ratio (NLR) and delivers soluble IL-6R to trigger further endothelial activation.
• Autoimmune Amplification: Even in euthyroid individuals, elevated thyroid autoantibodies (TgAb and TPOAb) correlate with a Th1/Th17-dominant cytokine profile (TNF-α, IFN-γ, IL-17, and IL-23) and elevated systemic inflammatory indices (such as NLR and the systemic inflammatory index) independent of active thyroid hormone levels.

Bottom line

• Chronic low-grade inflammation operates as a self-perpetuating feedback loop where fatty acid imbalance, vascular scavenger receptor activation, neuroendocrine leukocyte mobilization, and subclinical thyroid autoimmunity converge to drive endothelial injury and impair endogenous immune resolution.