Some studies suggest
thyroid hormones may regulate the human immune system. In order to evaluate the effect of
thyroid hormone deficiency on antibody production, we evaluated serum
IgA and
IgM concentrations in 83 children with
congenital hypothyroidism (CH), diagnosed by neonatal screening. Patients were compared to two healthy, age-matched control groups. Patients with permanent CH had a significantly higher frequency of undetectable
IgA concentrations (
thyroid agenesis, P<10(-5); thyroid ectopy, P=0.013) and lower concentrations of
IgA (
thyroid agenesis, P<10(-6); thyroid ectopy, P<10(-5); dyshormonogenesis, P=0.0002) and
IgM (
thyroid agenesis, P=0.0002; thyroid ectopy, P<10(-6); dyshormonogenesis, P=0.0017) compared to control group. No difference was observed between patients with transient
hypothyroidism and controls. A significant correlation was observed between serum
IgA and
IgM concentrations and fT4 levels.
IgA and
IgM deficiency is correlated with the severity of
congenital hypothyroidism and may help to evaluate the duration and severity of
thyroid hormone deficiency during prenatal life.