Isolated IgA deficiency accompanied by autoimmune thyroid disease

Selective immunoglobulin (Ig) A deficiency is reported to occur in 1 in 16,000 in Japan and has been reported to be complicated with various autoimmune diseases. A 49-year-old woman was diagnosed as having autoimmune thyroid disease. Her serum IgA, IgM and IgG were revealed to be 4.1, 154 and 1930 mg/dl, respectively. Severe skin eruption which occurred with 30 mg/day of methimazole (MMI) or 300 mg/day of propylthiouracil (PTU), was relieved by reducing MMI to 15 mg/day and administering anti-allergic drugs. Although the influence of IgA deficiency on autoimmunity and allergy still remains unclear, this is a report of IgA deficiency associated with autoimmune thyroid disease.