Clinical Symptoms in Adults with Selective IgA Deficiency: A Case-Control Study
Selective IgA deficiency (SIgAD) is the most common primary immunodeficiency in Caucasians with a prevalence of 1/600 and is generally considered a mild disorder. In this study, the clinical status of 32 adults with SIgAD was investigated and compared to 63 age- and gender matched controls, randomly selected from a population database. The SIgAD individuals reported significantly more often contracting various upper and lower respiratory infections, with 8 (25.0 %) having been diagnosed with ≥1 pneumonia in the preceding two years, compared to one (1.6 %) control (p < 0.001). Furthermore, the SIgAD individuals were found to have increased proneness to infections and increased prevalence of allergic diseases and autoimmunity, with a total of 84.4 % being affected by any of these diseases, compared to 47.6 % of the controls (p < 0.01). This study challenges the common statement of SIgAD being a mild form of immunodeficiency. It also highlights the importance of using matched controls in PID clinical research to better detect clinically important manifestations.
KeywordsPrimary immunodeficiency IgA deficiency infections autoimmunity allergy
We are grateful to all the individuals participating in the study, and to Hilary Hocking, Östersund, Sweden, for language revision.
This study was supported by the Landspitali University Hospital Research Fund, the Icelandic Research Fund, Karolinska Institutet (KI Fonder), Stockholm, Sweden and Division of Research and Development, Primary Care, County Council of Uppsala, Sweden.
Conflict of Interest
No conflict of interest is reported for any of the authors.
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