Profiling inflammatory signatures of schizophrenia: A cross-sectional and meta-analysis study

We aimed to profile a broad panel of inflammatory markers in patients with schizophrenia and healthy controls. Additionally, we performed a meta-analysis of chemokine alterations that have not been subjected to quantitative synthesis so far. We recruited 78 patients with schizophrenia and 78 healthy controls, and measured inflammatory markers using the Luminex technology. After adjustment for multiple testing, we found elevated levels of interleukin (IL)-1 receptor antagonist (IL-1RA), IL-6, IL-7, IL-8, IL-9, IL-10, IL-13, interferon-γ, eotaxin-1, granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemoattractant protein-1 (MCP-1), platelet-derived growth factor with two B subunits (PDGF-BB), macrophage inflammatory protein (MIP)-1α, MIP-1β, vascular endothelial growth factor A (VEGF-A) and RANTES in multiple-episode schizophrenia (MES) patients. These differences, except for the difference in eotaxin-1 levels, appeared to be significant after co-varying for the dosage of antipsychotics. There were no significant differences in the levels of immune markers between first-episode schizophrenia (FES) patients and controls. Our meta-analysis revealed elevated levels of MCP-1 in first-episode psychosis (FEP) patients and MES individuals. Other chemokine alterations (elevated levels of IL-8, eotaxin-1 and MIP-1β) were present only in MES patients. Our results indicate that dysregulation of immune response in schizophrenia develops with illness progression or appears as a long-term medication effect. Chemokine alterations are another example of aberrant immune response in schizophrenia patients. Elevated levels of MCP-1 might represent trait markers since these alterations were found in FEP and MES patients. Other chemokine alterations might be the markers of disease progression or might represent medication effects.