Autism spectrum disorders (ASD) has been associated with the malfunctions of multiple biological systems and pathways, especially the cytokines of the immune system. The altered immune functions may influence crucial neurodevelopmental processes (Napolioni et al., 2013).
For example, the cytokines adipokines from the adipose tissue have been suggested to have systemic effects in those with ASD. In a study of plasma samples from 30 ASD patients and 19 controls, the levels of three adipokines including adiponectin, leptin and resistin were analyzed (Rodrigues et al., 2014). The study found lower levels of resistin and higher levels of leptin in ASD patients, compared to those controls. In addition, a negative association between the plasma levels of the cytokine adiponectin and the severity of ASD symptoms was observed. The altered plasma levels of the adipokines may be potential markers of the physiological changes in ASD.
In another study of 25 discordant sibling pairs, plasma-cytokine profiling was used to evaluate the relationship between cytokine levels and relevant traits (Napolioni et al., 2013). Although no significant differences were observed in the plasma-cytokine tests between those with ASD and their non-autistic siblings, the study did find associations between the cytokine interleukin-1β (IL-1β) and the clinically quantitative traits of ASD.
In summary, these studies have indicated that immune dysfunctions may be associated with the essential features of ASD. Further studies are still needed to find out the connections between immune responses and the mechanisms of autism spectrum disorders.
Napolioni V, Ober-Reynolds B, Szelinger S, Corneveaux JJ, Pawlowski T, Ober-Reynolds S, Kirwan J, Persico AM, Melmed RD, Craig DW, Smith CJ, Huentelman MJ. Plasma cytokine profiling in sibling pairs discordant for autism spectrum disorder. J Neuroinflammation. 2013 Mar 14;10:38. doi: 10.1186/1742-2094-10-38.
Rodrigues DH, Rocha NP, Sousa LF, Barbosa IG, Kummer A, Teixeira AL. Changes in adipokine levels in autism spectrum disorders. Neuropsychobiology. 2014;69(1):6-10. doi: 10.1159/000356234.