Insights into the clinical spectrum of selective IgA deficiency: Data from two centers

Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency, yet its clinical presentation ranges from asymptomatic cases to individuals suffering from recurrent infections, allergic manifestations, and autoimmune disorders. Limited data exist regarding the immunological and clinical profiles of pediatric patients with sIgAD in Türkiye.

We conducted a retrospective analysis of 45 pediatric patients (20 females and 25 males) diagnosed with sIgAD and followed at two tertiary care centers. Demographic features, allergic and autoimmune comorbidities, and immunological parameters were evaluated. Lymphocyte subset analyses and immunoglobulin subclass levels were recorded. Associations between IgG3/IgG4 subclass deficiencies and infection frequency were assessed using the Mann-Whitney U test.

The median current age was 102 months (range: 48-204), with a median age of symptom onset at 24 months (range: 1-186), referral at 88 months (range: 6-199), and diagnosis at 87 months (range: 48-192). A history of at least one allergic disease, including asthma, allergic rhinitis, and/or atopic dermatitis, was present in 66.7% of patients. Autoimmune conditions were identified in 13.3%, including Hashimoto's thyroiditis, vitiligo, and immune thrombocytopenic purpura. No statistically significant differences in the frequencies of upper respiratory tract infections, pneumonia, otitis, or viral infections were observed between patients with low versus normal/high IgG3 or IgG4 levels (all P > 0.05).

Our findings highlight the high prevalence of allergic diseases and the clinical heterogeneity of sIgAD in children. Moreover, isolated IgG3 or IgG4 subclass deficiencies may not independently influence infection susceptibility. Longitudinal studies are warranted to better define the prognostic role of immunoglobulin subclasses in pediatric sIgAD.