Fig. 3

Prevalence of hypogammaglobulinemia among pediatric patients with autoimmune disease stratified by severity. For subjects younger than 16 years old, severity was defined as: mild, IgG level of 2–3 standard deviations below the mean for age-matched controls; moderate, IgG level of 3–4 standard deviations below the mean; severe, IgG level below four standard deviations below the mean. For subjects older than 16 years old, severity was defined as: mild, 400–599 mg/d; moderate, 200–399 mg/dL; and severe, 0–199 mg/dL