Serial mitogen-stimulated cytokine production from continuously ill patients with schizophrenia

Aberrant activation of the immune system has been implicated in an increasingly large number of disease states and can influence cognition, mood, and memory. There is a long and controversial history of reports of immune activation associated with schizophrenia. In this study, we measured mitogen-stimulated cytokine levels serially in 100 medication-stabilized continuously ill subjects with schizophrenia and compared and contrasted them with mitogen-stimulated cytokine levels from 51 normal volunteers. The subjects with schizophrenia had consistently higher mitogen-stimulated IL-2 levels and lower IL-6 levels than the normal volunteers. These effects could not be explained by medications, smoking, or other clinical variables. We conclude that continuously symptomatic medication-stabilized subjects with schizophrenia have a mitogen-stimulated cytokine expression pattern that is suggestive of ongoing immune activation.