Selective IgA deficiency – does partial mean negligible?

Introduction
Selective immunoglobulin A deficiency (SIgAD) is the most common primary immunodeficiency in the Caucasian population. The current definition describes SIgAD as serum IgA level below 0.07 g/l in individuals of four years of age or older with normal immunoglobulin G and M levels, in whom other causes of hypogammaglobulinaemia have been excluded. Most patients with SIgAD are asymptomatic, but some of them suffer from recurrent infections, primarily involving the respiratory system, allergies, autoimmune disorders, and malignancies. In contrast to “absolute” SIgAD, the clinical relevance of partial SIgAD has not yet been determined.

Aim of the study
To compare the clinical course of absolute and partial SIgAD in children.

Material and methods
The study was conducted through a retrospective review of the medical records of 25 children with absolute and 33 children with partial SIgAD, aged between 4 and 18 years, for the occurrence of recurrent respiratory, urinary, and gastrointestinal tract infections, as well as allergy, autoimmunity, and malignancies.

Results
Respiratory tract infections were the most common clinical manifestation in both variants of SIgAD and affected nearly two-thirds of patients with absolute and about three-quarters with partial SIgAD. Apart from autoimmunity in total, which occurred more often in children with absolute than partial SIgAD (44% vs. 12.12%, p = 0.006), no statistically significant differences were found between the incidence of the analysed conditions in both groups.

Conclusions
Due to the similar clinical course of both variants of SIgAD, all symptomatic patients should receive specialist care and undergo systematic follow-up visits. In children with autoimmune diseases basic immunology screening should be considered.