Research paperElevation of plasma neutrophil gelatinase-associated lipocalin (NGAL) levels in schizophrenia patients

- Immuno-inflammation markers presented a increased trend in psychiatric patients.
- NGAL highly expressed in schizophrenia patients.
- NGAL in bipolar disorder group was significantly higher than in the depression group.

BackgroundPsychiatric diseases are usually accompanied by immune dysregulation and activation of the inflammatory response system. However, the characteristics of immunoinflammatory markers in psychiatric diseases are not well defined.MethodsSeventy-three patients with psychiatric diseases were divided into four groups, including a schizophrenia group, an anxiety disorder group, a unipolar depression group, and a bipolar disorder group, according to the ICD-10 and DSM-IV codes. Neutrophil gelatinase-associated lipocalin (NGAL) and associated classical immunoinflammatory markers including C-reactive protein (CRP), Th1/Th2 cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ), total leukocyte count (TLC), and neutrophilic granulocyte percentage (NEU%) were analysed; patients with physical diseases were excluded to avoid confounders. Fifteen healthy, age- and gender-matched individuals served as controls.ResultsCompared with the corresponding values in the control group, the level of CRP in each psychiatric disease group, the levels of IFN-γ and NGAL in the schizophrenia group, and the NEU% in the depression group were significantly elevated (P < 0.05). Compared with the levels in the schizophrenia group, the levels of CRP in the bipolar disorder and depression groups, the level of IFN-γ in the bipolar disorder group, and the levels of NGAL in the anxiety disorder and depression groups were significantly decreased (P < 0.05). Compared with the depression group, the bipolar disorder group showed significant elevation the NGAL level.LimitationThe sample size was relatively small.ConclusionsImmunoinflammatory markers were elevated in patients with psychiatric diseases, especially schizophrenia. We are the first to report that the level of NGAL is significantly increased in schizophrenia patients.