Autoantibodies in patients with 22q11.2 deletion syndrome and psychosis

The 22q11.2 deletion syndrome occurs in roughly 1 in 2000 live births. It is one of the most common chromosomal conditions worldwide. It has a frequency of psychosis in adulthood of 25%, making it the most common known etiology for psychosis. The mechanisms of disease for psychosis are poorly understood; however, there are data supporting a role for inflammation. Given the altered immune system in 22q11.2 deletion syndrome, this study examined autoantibodies associated with psychosis.

The underlying hypothesis that we tested was whether patients with psychosis have an immune landscape different from that of patients without psychosis. In this study, we tested whether increased autoantibody levels were seen in patients with psychosis.

We utilized the University of Texas Southwestern autoantibody array to measure levels of autoantibodies in patients and controls. The analyses were performed using a 2-tailed Student t test with Benjamini-Hochberg correction for false discovery rate.

In general, both child and adult patients had lower levels of autoantibodies than the controls. The adult patients with psychosis, however, had significantly higher autoantibody levels than the adult patients without psychosis. Of the 10 patients with psychosis, 8 had levels of autoantibodies to single-stranded DNA that were more than 2 SDs higher than in the controls. This was not accompanied by clear clinical autoimmunity.

Patients with 22q11.2 deletion syndrome and psychosis appear to have immunologic characteristics different from those of patients who carry the deletion but do not have psychosis. Overall, autoantibody levels were significantly higher in patients with psychosis. This finding may define a high-risk group within the population with 22q11.2 deletion syndrome.