New Insights into the Immune Landscape of Depression and Suicide

Strategic Insights -

Researchers from University Hospital Montpellier, France have conducted a study to better understand the biological mechanisms underlying depression and recent suicide attempts. The study compared the immunological profiles of patients with major depressive episodes (MDE) with and without a recent suicide attempt (SA) to those of healthy controls. The results, published in Translational Psychiatry, provide new insights into the immune landscape of MDE and recent SA, and highlight the need for future longitudinal studies to disentangle state- and trait-like biological changes associated with SA.

Key Takeaways:

  • The study found that the immunological profiles of MDE patients with and without a recent SA were significantly different from those of healthy controls, particularly in terms of soluble immune and growth factors, cellular immunity, and neuroinflammatory markers.
  • Three primary dimensions structuring the biological markers were identified: soluble immune and growth factors, cellular immunity, and neuroinflammatory markers.
  • Lower percentages of CD3 and CD8CD3, higher basophil count, and lower serotonin levels differentiated MDE without SA from healthy controls.
  • An increased neutrophil-to-lymphocyte ratio and basophil count, and lower serotonin levels differentiated recent SA from healthy controls.
  • The findings provide new insights into the immune landscape of MDE and recent SA, and underscore the need for future longitudinal studies to disentangle state- and trait-like biological changes associated with SA.
  • Aiste Lengvenyte from University Hospital Montpellier and colleagues from Lapeyronie Hospital, University Hospital Montpellier, were involved in the study, which was supported by Agence Nationale de la Recherche and Fondation de France.

Statistics:

  • 106 participants were included in the study, consisting of 36 MDE patients without SA, 35 MDE patients with recent SA, and 35 healthy controls.
  • The study found distinct immunological profiles between MDE patients with and without SA, and those of healthy controls.
  • CD3 and CD8CD3 percentages were significantly lower in MDE patients without SA compared to healthy controls (55.6% vs. 66.5%).
  • Basophil count was significantly higher in MDE patients without SA compared to healthy controls (9.1% vs. 6.2%).
  • Serotonin levels were significantly lower in MDE patients without SA compared to healthy controls (10.8% vs. 13.9%).
  • Neutrophil-to-lymphocyte ratio was significantly increased in MDE patients with recent SA compared to healthy controls (2.4 vs. 1.9).
  • Basophil count was significantly higher in MDE patients with recent SA compared to healthy controls (10.5% vs. 6.2%).

Sources:

  • Lengvenyte, A., Blaquiere, M., Dubois, J., Bonnin, M., Bourret, J., Hamzeh-Cognasse, H., Olie, E., Cognasse, F., Marchi, N., & Courtet, P. (2025). Integrating cellular and soluble immune signatures of major depression with and without recent suicide attempts. Translational Psychiatry, 15(1), 377.
  • NewsRx. Studies from University Hospital Montpellier Yield New Data on Depression (Integrating cellular and soluble immune signatures of major depression with and without recent suicide attempts). Mental Health Weekly Digest. October 20, 2025; p 1129.