Decreased levels of soluble intercellular adhesion Molecule-1 (sICAM-1) in unmedicated and medicated schizophrenic patients

Background: The soluble intercellular adhesion molecule-1 (sICAM-1) is a marker for the activation of the cellular immune system. Since an activation of the immune system has been observed in a part of the schizophrenic patients, we measured the serum levels of soluble ICAM-1 (sICAM-1) in schizophrenic patients and correlated them to the patient’s psychopathology. Methods: To monitor a possible effect of antipsychotic therapy, 36 schizophrenic patients were examined twice: first without antipsychotic medication immediately after admission to the hospital and then, after clinical improvement before discharge. The results were compared with those of 36 age- and gender-related healthy individuals. Results: The schizophrenic patients showed significantly decreased serum levels of sICAM-1 at the first examination (248 ± 95 ng/mL) and at re-examination (266 ± 95 ng/mL) compared with the comparison group (323 ± 74 ng/mL). Patients with more pronounced negative symptoms showed higher levels of sICAM-1 at the first examination. Conclusions: We conclude that reduced sICAM-1 levels in schizophrenia indicate a reduced activity of the cellular immune system in at least a subgroup of schizophrenic patients.