Increased serum levels of high mobility group box 1 protein in patients with autistic disorder.

Background: High mobility group box 1 (HMGB1) is a highly conserved, ubiquitous protein that functions as an activator for inducing the immune response and can be released from neurons after glutamate excitotoxicity. The objective of the present study was to measure serum levels of HMGB1 in patients with autistic disorder and to study their relationship with clinical characteristics.

Methods: We enrolled 22 adult patients with autistic disorder (mean age: 28.1+/-7.7 years) and 28 age- and gender-matched healthy controls (mean age: 28.7+/-8.1 years). Serum levels of HMGB1 were measured by enzyme-linked immunosorbent assay (ELISA).

Results: Compared with healthy subjects, serum levels of HMGB1 were significantly higher in patients with autistic disorder (10.8+/-2.6 ng/mL versus 5.6+/-2.5 ng/mL, respectively, P<0.001). After adjustment for potential confounders, serum HMGB1 levels were independently associated with their domain A scores in the Autism Diagnostic Interview-Revised, which reflects their impairments in social interaction.

Conclusions: These results suggest that HMGB1 levels may be affected in autistic disorder. Increased HMGB1 may be a biological correlate of the impaired reciprocal social interactions in this neurodevelopmental disorder.