Pronounced immunological abnormalities in unmedicated first episode as compared to chronic schizophrenia patients

There is major evidence for the involvement of immunological processes in the pathophysiology of schizophrenia. Especially alterations of T-cell function and activation of the inflammatory response system appear to be linked to schizophrenia. A mild chronic inflammation process has been proposed and repeated findings of altered serum cytokine levels led to the hypothesis of a TH2 shift or cytokine imbalance in schizophrenia. We investigated serum levels of TH1 and TH2 related cytokines and immune markers in 25 patients suffering an acute schizophrenic episode (all unmedicated, 22 neuroleptica-naïve) at different stages of disorder (18 first episode, FEP; 7 recurrent episode, REP) compared to 25 age and sex matched healthy controls.

In patients, we found an increase of the TH2 system cytokine IL-13 (p = 0.039) and a decrease of the TH1 system markers sICAM-1 (p = 0.011) and sIL-2R (p = 0.063, n. s.). Elevation of the pro-inflammatory cytokine IL-6 was not significant (p = 0.052). The effect of sIL-2R decrease was greater in the FEP subgroup (p = 0.01) of patients. We found no group differences in the other investigated immune markers: IL-4, IL-8, TNF-alpha, and Interferon-gamma, in which most readings were below the lower detection limit of the respective assay.

Our findings support the notion of a TH1/TH2 imbalance particularly in the acute manifestation phase of schizophrenia. In the long run, this may lead to the identification of cytokine patterns that are applicable as trait or state markers, may be helpful in making or ensuring diagnosis or in monitoring therapy.