Neuroimmune Dysregulation and the Role of IL-10 in Depression: A Systematic Review

Background: Treatment-resistant depression (TRD) represents a major clinical challenge and is increasingly associated with persistent neuroinflammatory processes. Evidence suggests that dysregulation of the immune system, particularly the imbalance between pro-inflammatory and anti-inflammatory cytokines, contributes to poor therapeutic response. In this context, interleukin-10 (IL-10) has emerged as a key mediator in regulating the inflammatory response. Objective: To systematically analyze the evidence on neuroimmune dysregulation in depression, with an emphasis on TRD, and to evaluate the potential role of IL-10 as a biomarker and modulator of therapeutic response. Methods: A systematic review was conducted in accordance with PRISMA guidelines. Fourteen studies were included, comprising randomized clinical trials, longitudinal studies, a prospective cohort study, and exploratory designs. Methodological quality was assessed using the RoB 2 tool and complementary approaches. Data were integrated through a qualitative analysis focused on inflammatory biomarkers and clinical outcomes. Results: The studies consistently showed an association between elevated levels of pro-inflammatory cytokines, such as IL-6 and TNF-α, and the severity of depressive symptoms, as well as reduced response to conventional treatments. Immunomodulatory interventions, including ketamine, pentoxifylline, and minocycline, were associated with clinical improvement, particularly in patients with elevated baseline inflammation. IL-10 appears to be involved in counter-regulatory neuroimmune processes associated with inflammatory balance. Conclusions: Neuroinflammation plays a central role in TRD. IL-10 may serve as a relevant biomarker and a potential target for personalized therapeutic strategies informed by immune profiles, through modulation of neuroinflammatory pathways.