Elevated Proinflammatory Markers in 22q11.2 Deletion Syndrome Are Associated With Psychosis and Cognitive Deficits

Objective: 22q11.2 deletion syndrome (22q11.2DS) is a neurogenetic disorder whose phenotype includes high rates of a schizophrenia-like psychotic disorder and immune system abnormalities. Thus, 22q11.2DS is an ideal model for studying the relationship between psychosis and inflammation. The aim of the present study was to identify inflammatory markers that may play a role in the pathophysiologic pathways associated with psychosis and cognitive deficits in 22q11.2DS.

Methods: Forty-nine individuals with 22q11.2DS (13 with psychotic disorders according to DSM-IV criteria and 36 without psychotic disorders) and 30 age- and sex-matched healthy controls underwent psychiatric and cognitive assessments at an outpatient clinic. Blood samples from all participants were analyzed for C-reactive protein (CRP), interleukin (IL)-6, IL-10, tumor necrosis factor alpha (TNFα), and IL-1 receptor antagonist levels. The study was conducted between August 2014 and September 2015.

Results: The 22q11.2DS participants had elevated levels of CRP (P = .004), IL-6 (P = .001), TNFα (P < .001), and IL-10 (P = .028) compared with controls. Furthermore, the psychotic 22q11.2DS participants had higher levels of IL-6 (P < .001) and IL-6/IL-10 ratio (used as an indicator for proinflammatory activation, P < .001) compared with the nonpsychotic 22q11.2DS individuals and controls. IL-6 levels and the IL-6/IL-10 ratio correlated with the severity of the cognitive deficits in the 22q11.2DS participants.

Conclusions: Our preliminary findings indicate an involvement of inflammatory processes in the pathophysiology of psychosis and cognitive deficits in 22q11.2DS and are in line with the accumulating evidence for the role of neuroinflammation in nonsyndromic schizophrenia.