IGHG3 and autoimmune polyendocrinopathy: Comparing the contribution of the individual subclasses between the study cohorts, we observed that children showed significantly less IgG2 than patients with APS and NHD (p < 0.001; p < 0.0001) and a higher IgG3 content than NHD and patients with APS (p < 0.0001; p < 0.001).