From the Guidelines
For testing immunosuppression, a comprehensive immune function assessment is recommended, including complete blood count with differential, CD4+ T-cell counts, immunoglobulin levels, complement levels, and lymphocyte subset analysis, as outlined in the most recent guidelines 1. This approach is crucial for evaluating the immune status of patients, particularly those on immunosuppressive medications like corticosteroids, calcineurin inhibitors, or biologics. The testing frequency depends on the underlying condition, medication regimen, and clinical status, but is typically performed every 3-6 months for stable patients and more frequently during medication adjustments or infections.
- Key components of the immune function assessment include:
- Complete blood count with differential to evaluate white blood cell populations
- CD4+ T-cell counts, with values below 200 cells/mm³ indicating severe immunosuppression
- Immunoglobulin levels (IgG, IgA, IgM)
- Complement levels (C3, C4)
- Lymphocyte subset analysis
- Specific functional assays may also be performed, such as lymphocyte proliferation tests in response to mitogens or antigens.
- For patients undergoing immunosuppressive therapy or chemotherapy, screening for HBV markers prior to immunosuppression is recommended, and all HBsAg-positive patients should receive antiviral prophylaxis or treatment 1.
- The risk of HBV reactivation can be high in HBsAg-positive and HBsAg-negative, anti-HBc positive patients receiving chemotherapy or immunosuppressive therapy, and prophylactic administration of nucleos(t)ide analogues can reduce this risk 1.
From the Research
Testing for Immunosuppression
To test for immunosuppression, several approaches can be considered:
- Complete blood counts and serologic tests of immunoglobulin levels, vaccine titers, and complement levels can be used as initial workup for suspected immune deficiencies 2
- Flow cytometric-based assays can be utilized to test immune cell function, such as neutrophil oxidative burst, NK cytotoxicity, intracellular cytokine production, and cellular signaling pathways 2
- Genetic testing can also be used to identify novel disorders, especially with the advancement of mass sequencing technologies 2
- Absolute lymphocyte counts (ALC) can be used to estimate CD4 counts in HIV-infected adults with virologic suppression and immune reconstitution 3
- Functional T-cell immunocompetence can be evaluated using a novel assay that measures ATP production in CD4(+) T-lymphocytes in response to stimulation, which can assess the functional response of lymphocytes independent of circulating cell numbers 4
Considerations for Testing
When testing for immunosuppression, it is essential to consider the following:
- Patient selection and medication selection are crucial, as some patients may not be suitable for certain therapies 5
- Screening for potential adverse events, such as tuberculosis testing before initiating biologics, may be necessary 5
- Regular monitoring of blood tests and potential side effects is required for certain therapies, such as thiopurines and methotrexate 5
- The use of anti-adhesion molecule therapy may be associated with a lethal central nervous system infection, and therefore, tends to be used as a third- or fourth-line therapy 5
Additional Testing Options
Other testing options for immunosuppression include:
- Autologous CD4/CD8 co-culture assay, which measures the ability of CD8(+) T lymphocytes to suppress viral production by infected autologous CD4(+) T lymphocytes 6
- This assay can provide a global readout of the CD8(+) T lymphocyte overall function against HIV-1 and can be used for longitudinal assessment of individual HIV-infected persons 6