From the Guidelines
A high level of Immunoglobulin A (IgA) in the blood is indicative of an overactive immune response or inflammation, which can be associated with various conditions such as chronic infections, autoimmune disorders, liver diseases, certain cancers, and inflammatory bowel diseases. The provided evidence does not directly address the implications of high IgA levels, but it discusses the diagnosis and management of primary immunodeficiency, including Selective IgA Deficiency (SIGAD) 1. According to the study, patients with serum IgA levels of less than the normal range for age but greater than 7 mg/dL should not be given a diagnosis of IgA deficiency 1.
Key Points to Consider
- Elevated IgA levels can occur in several conditions, including chronic infections, autoimmune disorders, liver diseases, certain cancers, and inflammatory bowel diseases.
- The significance of high IgA depends on the clinical context and should be interpreted alongside other symptoms and test results.
- Treatment focuses on addressing the underlying condition causing the elevation, rather than the high IgA level itself.
- Regular monitoring of IgA levels may be necessary to track disease progression or response to treatment for the underlying condition.
Clinical Implications
The study 1 highlights the importance of monitoring patients with SIGAD over time for the occurrence of complications, as most affected patients are asymptomatic, but some do have problems over time, including respiratory and gastrointestinal tract infections, atopy, autoimmune diseases, celiac disease, and malignancy. It is essential to interpret high IgA levels in the context of the patient's overall clinical presentation and medical history, and to consider additional tests to determine the underlying cause of the elevation 1.
From the Research
High IgA Levels
- A high IgA level can be an indicator of IgA nephropathy, a kidney disease characterized by the deposition of IgA antibodies in the kidneys 2, 3, 4, 5, 6
- IgA nephropathy can cause end-stage kidney disease in 15% to 20% of affected patients within 10 years and in 30% to 40% of patients within 20 years from the onset of disease 3
- The treatment of IgA nephropathy has been limited by several controversies in the literature, including the benefits of corticosteroids in addition to optimized renin-angiotensin system blockers (RASBs) 4
Treatment Options
- Corticosteroid therapy probably prevents decline in GFR or doubling of SCr in adults and children with IgA nephropathy and proteinuria 3
- Steroid therapy may induce complete remission, prevent doubling of serum creatinine, and lower urinary protein excretion 3
- Mycophenolate mofetil (MMF) had uncertain effects on the progression to ESKD, complete remission, doubling of SCr, GFR, protein excretion, infection, and malignancy 3
- Calcineurin inhibitors compared with placebo or standard care had uncertain effects on complete remission, SCr, GFR, protein excretion, infection, and malignancy 3
Clinical Efficacy of Drugs
- A model-based meta-analysis of drugs for clinical treatments of IgA nephropathy found that the order of efficacy of the 6 classes of drugs was as follows: corticosteroids > immunosuppressants > other drugs > renin-angiotensin system blockers > antiplatelet agents > N-3 fatty acids 5
- The results of this study provide an important reference for the rational clinical use of drugs for IgA nephropathy, and also provide a reliable efficacy standard for the development of new drugs for IgA nephropathy 5