D1.350 - Selective IgA deficiency and its association with allergic and autoimmune diseases

Selective immunoglobulin A (IgA) deficiency represents the most prevalent primary antibody deficiency. It is defined by markedly reduced or completely absent serum IgA concentrations, while serum levels of immunoglobulin M (IgM) and immunoglobulin G (IgG) remain within normal limits. IgA plays a pivotal role in mucosal immune defense, particularly within the gastrointestinal and respiratory tracts. Although more than 50% of affected individuals are asymptomatic, selective IgA deficiency may be associated with recurrent gastrointestinal and respiratory infections, as well as an increased prevalence of allergic and autoimmune disorders.Objective of this study was to evaluate the frequency of allergic and autoimmune disorders in children with IgA immunodeficiency.

We conducted a cross-sectional observational study including 50 pediatric patients with selective IgA deficiency to assess the prevalence of allergic and autoimmune diseases. The presence of allergic and autoimmune disorders was evaluated by specialist of allergology, immunology, rheumatology and otorhinolaryngology. 

Of the included children, 32 (64%) were male, and the mean age was 9.5 years. At least one allergic disease was identified in 38 patients (76%). Asthma was present in 26 patients (52%), allergic rhinitis in 21 (42%), atopic dermatitis in 8 (16%), and urticaria in 7 (14%). Autoimmune disorders were diagnosed in 21 patients (42%), including reactive arthritis in 13 (26%), juvenile idiopathic arthritis in 8 (16%), Hashimoto’s thyroiditis in 2 (4%), and systemic lupus erythematosus in 1 (2%). PFAPA syndrome was observed in 4 patients (8%). A coexistence of at least one allergic and one autoimmune disease was documented in 18 patients (36%).

This study demonstrates that asthma and allergic rhinitis are the predominant clinical manifestations in patients with selective IgA deficiency. In addition, an increased prevalence of other allergic and autoimmune diseases and coexistence of allergy and autoimmunity was observed when compared with available data from the general population. Awareness of this association is important for early diagnosis and multidisciplinary management.