The phenomenological uniqueness of each patient with schizophrenia is determined by complex symptomatology, particularly the overlapping of symptoms and their prominence in certain phases of this mental disorder. Establishing biological markers is an important step in the further objectivisation and quantification of schizophrenia. Identifying the cytokine profiles that precede a psychotic episode could direct the strategies for relapse prevention and be useful in predicting disease progression and treatment response. In the context of infl ammation, TGF-β exerts potent anti-inflammatory and immunosuppressive functions by inhibiting pro-inflammatory cytokine synthesis, but it can also have pro-inflammatory functions through its stimulatory effects on inflammatory Th17 cells. It has been shown that the T helper cell type-1 and type-17 responses are reduced and type-2 response is increased in patients with schizophrenia. Both data from the literature and our results also indicate the presence of an anti-inflammatory response through production of the TGF-β regulatory cytokine. A meta-analysis of plasma cytokine alterations suggested that TGF-β is the state marker for acute exacerbation of schizophrenia, and we showed that TGF-β can also be a valuable marker for psychosis. Hyperactivity of TGF-β signalling pathways in schizophrenia may be both a neuroprotective mechanism and a possible therapeutic target.
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