[Autoimmune diseases and autoantibodies in pediatric patients and their first-degree relatives with immunoglobulin A deficiency]

Introduction: Clinical manifestations of Immunoglobulin A Deficiency (IgAD) include recurrent infections, atopy and autoimmune diseases. However, to our knowledge, the concomitant evaluations of autoimmune diseases and autoantibodies in a cohort of IgAD patients with current age > 10 years-old and their relatives have not been assessed.

Objectives: To evaluate autoimmune diseases and the presence of autoantibodies in IgAD patients and their first-degree relatives.

Methods: A cross-sectional study was performed in 34 IgAD patients (current age > 10 years-old) and their first-degree relatives. All of them were followed at a tertiary Brazilian primary immunodeficiency center: 27 children/adolescents and 7 of their first-degree relatives with a late diagnosis of IgAD. Autoimmune diseases and autoantibodies (antinuclear antibodies, rheumatoid factor, and anti-thyroglobulin, anti-thyroperoxidase and IgA class anti-endomysial antibodies) were also assessed.

Results: Autoimmune diseases (n=14) and/or autoantibodies (n=10, four of them with isolated autoantibodies) were observed in 18/34 (53%) of the patients and their relatives. The most common autoimmune diseases found were thyroiditis (18%), chronic arthritis (12%) and celiac disease (6%). The most frequent autoantibodies were antinuclear antibodies (2%), anti-thyroglobulin and/or anti-thyroperoxidase (24%). No significant differences were observed in the female gender, age at diagnosis and current age in IgAD patients with and without autoimmune diseases and/or presence of autoantibodies (p>0.05). The frequencies of primary immunodeficiency's in family, autoimmunity in family, atopy and recurrent infections were similar in both groups (p>0.05).

Conclusion: Autoimmune diseases and autoantibodies were observed in IgAD patients during follow-up, reinforcing the necessity of a rigorous and continuous follow-up during adolescence and adulthood.