The Effect of Ketamine on the Immune System in Patients with Treatment-Resistant Depression
International Journal of Molecular Sciences August 1, 2025 Ł. Szałach, Klaudia Ciesielska-Figlon, A. Daca et al. 7 citations
In people with treatment-resistant depression, a single intravenous dose of ketamine (0.5 mg/kg) produces rapid, temporary shifts in immune markers. Within 4 hours, total T cells and certain helper T-cell subsets increased, while by 24 hours, activated T cells declined and the ratio of helper to cytotoxic T cells decreased. Blood levels of the anti-inflammatory cytokine IL-10 rose, while the pro-inflammatory cytokines IL-6 and IL-8 fell—IL-8 remained lower for at least 24 hours. In laboratory experiments, high-dose ketamine boosted the growth of helper T cells from depressed patients and increased secretion of IL-8 and IL-6 from activated immune cells. The sustained drop in IL-8 points to an anti-inflammatory effect and may serve as a biomarker for treatment response.