Significant correlations between vitamin D deficiency, anti-lipopolysaccharide antibodies, and interleukin-6 in schizophrenia suggest there may be multiple potential pathways related to the elevation of interleukin-6 in psychosis, according to study results published in Schizophrenia Research.
Increases in the levels of the pro-inflammatory cytokine interleukin-6 are associated with all phases of schizophrenia and may be associated with other markers of inflammation. Therefore, the researchers in the current study investigated potential contributing mechanisms for interleukin-6 elevation by measuring and comparing levels of interleukin-6, vitamin D, C-reactive protein, and anti-lipopolysaccharide antibodies in young adults, adolescents, and children with psychosis (n=47), individuals with a high clinical risk of developing psychosis (n=17), and unaffected controls (n=33).
Diagnoses were determined by a psychiatrist using the MINI-Neuropsychiatric Interview. Chemiluminescent microparticle immunoassay was used to measure 25(OH)D in serum, and ELISA was used to measure levels of interleukin-6, C-reactive protein, and anti-lipopolysaccharide antibodies.
The researchers saw significantly elevated levels of interleukin-6 in the psychosis group relative to the control group (Wald χ2 = 5.11; P =.024), as well as increased levels of C-reactive protein (Wald χ2 = 5.11; P =.024). Elevated levels of interleukin-6 in the psychosis group were positively correlated with immunoglobulin A (IgA) anti-lipopolysaccharide antibodies (r = 0.36; P =.02) and negatively correlated with serum vitamin D levels (r = −0.49; P <.0001).
The study investigators concluded that the biomarkers of increased interleukin-6, IgA anti-lipopolysaccharide antibodies, and vitamin D deficiency “collectively may contribute to the inflammatory state in patients with psychosis. . . .Clinical trials of vitamin D may prove to be a simple intervention that could improve clinical symptoms and may play a significant role in prevention as well.”
Delaney S, Fallon B, Alaedini A, et al. Inflammatory biomarkers in psychosis and clinical high risk populations [published online November 9, 2018]. Schizophr Res. doi: 10.1016/j.schres.2018.10.017