The Prevalence of Selective and Partial Immunoglobulin A Deficiency in Patients with Autoimmune Polyendocrinopathy

Autoimmune disorders are reported as presenting signs in patients with immunoglobulin A (IgA) deficiency. Herein, we aim to evaluate serum IgA among patients with autoimmune polyendocrinopathy.

Patients with two or more autoimmune endocrinopathies were selected and the serum IgA levels were measured. Patients with an isolated low serum IgA (<7 mg/dL) after exclusion of other causes of hypogammaglobulinemia were considered as selective IgA deficiency (SIgAD), while partial IgA deficiency (PIgAD) was defined as IgA levels below lower limits of IgA normal range for age but higher than 7 mg/dL.

Fifty-three patients (19 [35.8%] male and 34 [64.2%] female) with autoimmune polyendocrinopathy enrolled in the study. Parental consanguinity and positive family history of autoimmunity were reported in 38.0% and 52.9% of patients, respectively. Overall, IgA deficiency was observed in 5 (9.4%) patients including PIgAD in 3 (5.7%) and SIgAD in 2 (3.8%) patients. Among IgA deficient patients, the first autoimmune disorder was developed at earlier ages (p = .002), and the prevalence of infection (p = .002), lymphoproliferation (p = .021), and overlap between insulin-dependent diabetes mellitus and autoimmune thyroiditis (p = .032) were significantly higher than patients with normal IgA. Also, the number of autoimmune comorbidities was closely correlated with the occurrence of IgA deficiency (p = .008).

The prevalence of IgA deficiency in patients with autoimmune polyendocrinopathy is higher than that in the general population. In these patients, immunologic workup may lead to early diagnosis of inborn error of immunity, which can positively impact the evolution of complications and even management of the autoimmune disorders.