From the Guidelines
The recommended approach for immune system screening in patients with recurrent infections begins with a comprehensive stepwise evaluation based on infection history and clinical presentation. Initial screening should include complete blood count with differential, immunoglobulin levels (IgG, IgA, IgM, IgE), and antibody responses to vaccines (tetanus, pneumococcal) 1. If these are abnormal or if infections persist, more specialized testing is warranted, including lymphocyte subset analysis (T, B, and NK cell counts), complement levels (CH50, C3, C4), and specific antibody production assessment. The evaluation should be tailored to the infection pattern—recurrent sinopulmonary infections suggest antibody deficiencies, while opportunistic infections point toward T-cell defects 1.
Some key points to consider in the evaluation process include:
- Hypersensitivity to environmental allergens, food allergens, or both might be an important element of and diagnostic clue for a variety of primary immunodeficiency disorders (PIDDs) 1
- Initial evaluation is guided by the clinical presentation, with screening tests applied and followed by advanced tests as indicated 1
- For patients with suspected phagocyte disorders, neutrophil function tests like oxidative burst assays should be performed
- Timing is important, as testing during active infection may yield misleading results
The goal of this systematic approach is to efficiently identify immune defects while avoiding unnecessary testing, ultimately leading to appropriate management strategies for patients with recurrent infections. By following this stepwise evaluation, clinicians can provide personalized care and improve outcomes for patients with immune system disorders.
From the Research
Immune System Screening Approach
The recommended approach for immune system screening in patients with recurrent infections involves a combination of clinical evaluation and laboratory tests.
- History analysis and physical examination are essential tools in identifying underlying conditions that may be contributing to recurrent infections 2.
- Laboratory tests, such as lymphocyte subsets, proliferative response to mitogens, and specific antibody responses, can help characterize the immune profile and clinical manifestations of patients with suspected immunodeficiency 3, 4.
- The evaluation of patients with suspected immunodeficiency should include a thorough clinical history, physical examination, and laboratory tests, such as complete blood count, immunoglobulin levels, and lymphocyte subset counts 5, 6.
Considerations for Specific Patient Populations
- In adults with recurrent upper respiratory tract infections, selective IgG3 subclass deficiency should be considered, especially if they have concurrent atopic diseases such as allergic rhinitis or asthma 3.
- Patients with Ataxia-Telangiectasia, a genetic condition leading to neurological defects and immune deficiency, require longitudinal evaluation of their immune deficiency, including clinical history, immunological data, and lymphocyte subset counts 4.
- In an allergy practice, determining if an immune defect is likely to be present can be problematic, and guidelines concerning clinical presentation, laboratory evaluation, and treatment options can aid the practicing clinician 5.
Laboratory Tests and Interpretation
- Office tests, such as complete blood count, immunoglobulin levels, and lymphocyte subset counts, can be obtained for initial screening, and their interpretation can help identify patients with suspected immunodeficiency 6.
- Specific antibody responses to tetanus toxoid and pneumococcal antigens can help assess the immune function of patients with recurrent infections 3.
- Lymphocyte subset counts and proliferative responses to mitogens can help characterize the immune profile of patients with suspected immunodeficiency 3, 4.