Patients with severe autism had significantly higher serum IL-17A levels than children with mild to moderate autism (P = 0.01) (Table 1, Figure 2), and the frequency of increased serum IL-17A levels was significantly higher in children with severe autism (19/28; 67.9%) than in patients with mild to moderate autism (3/17; 17.6%) (P = 0.001). Here, IL17A is linked to autism.