Immune Biomarkers in Depression: From Inflammatory Signatures to Precision Psychiatry

Objective. To review current evidence on immune biomarkers in major depressive disorder and their relevance for precision psychiatry.

Methods. A narrative review of studies examining inflammatory markers, immune cell alterations and mechanistic pathways linking immune activation to depression.

Results. Consistent evidence indicates that a subset of patients with depression exhibits elevated inflammatory markers, including C-reactive protein, interleukin-6 and tumor necrosis factor-alpha. Immune activation influences neurotransmission, neuroplasticity and stress-response systems, particularly through the kynurenine pathway and neuroinflammatory processes. These alterations are associated with specific symptom profiles and may predict differential treatment response.

Conclusions. Immune biomarkers represent a promising tool for identifying biologically distinct subtypes of depression and may contribute to the development of personalized treatment strategies within precision psychiatry.