Activation of the Inflammatory Response System in Autism

<i>Background/Aim:</i> There is now some evidence that autism may be accompanied by abnormalities in the inflammatory response system (IRS). Products of the IRS, such as proinflammatory cytokines, may induce some of the behavioral symptoms of autism, such as social withdrawal, resistance to novelty and sleep disturbances. The main aim of the present study was to examine whether autism is accompanied by an activation of the IRS. <i>Methods:</i> We measured the production of interleukin (IL)-6, IL-10, the IL-1 receptor antagonist (IL-1RA), interferon (IFN)-γ and tumor necrosis factor (TNF)-α by whole blood and the serum concentrations of IL-6, the IL-2 receptor (IL-2R) and IL-1RA. <i>Results:</i> This study showed a significantly increased production of IFN-γ and IL-1RA and a trend toward a significantly increased production of IL-6 and TNF-α by whole blood of autistic children. There were no significant differences in the serum concentrations of IL-6, IL-2R and IL-1RA between autistic and normal children. <i>Conclusions:</i> These results suggest that autism may be accompanied by an activation of the monocytic (increased IL-1RA) and Th-1-like (increased IFN-γ) arm of the IRS. It is hypothesized that increased production of proinflammatory cytokines could play a role in the pathophysiology of autism.