Acquisition of Selective IgA Deficiency in Juvenile Idiopathic Arthritis after Immunosuppressive Treatment

Abstract

Selective IgA deficiency is the most frequent primary immunodeficiency and is associated with an increased rate of respiratory infections in susceptible patients. Juvenile idiopathic arthritis is an autoimmune disease in children affecting the joints and is frequently treated with mild to moderately active immunosuppressive medications. We describe a pediatric patient with juvenile idiopathic arthritis who developed a selective IgA deficiency at age 4 years, with well-documented prior IgA levels within the normal range for that age. This girl was previously diagnosed with arthritis at age 2 years; she was treated with methotrexate starting at age 24 months, and etanercept for 18 months starting at age 32 months. The development of IgA deficiency occurred after discontinuation of etanercept treat ment. She did not exhibit an increased rate of infections or other clinical signs of immunodeficiency. A work-up for immunodeficiency demonstrated increased levels of transitional B-cells, but no other abnormal findings. Congenital IgA deficiency is well known to be linked to autoimmune diseases. Acquired IgA deficien cy has previously been described in a very small number of pediatric and adult patients, and is usually associated with some form of immune dysregulation or inciting event. Four patients with juvenile arthritis with acquired IgA deficiency of varying levels have been reported, but biologic agents have not been implicated previously.