Activated CD21 low CD38- %

Optimal Result: 1.2 - 9 % of CD19.

Lymphocyte Subset Panel 2

From Healthmatters.io Team

Lab Results Explained and Tracked

Activated CD21low CD38- %

The Activated CD21low CD38- % biomarker measures the proportion of B cells in the bloodstream characterized by low expression of CD21 (complement receptor 2) and absence of CD38 (a marker of activation and differentiation). These cells represent a subset of atypical or activated B cells, often associated with immune dysregulation, chronic activation, or pathological conditions.

Understanding CD21low CD38- B Cells

CD21 (Complement Receptor 2): A protein expressed on mature B cells that facilitates immune responses by interacting with complement-coated antigens. Reduced CD21 expression may indicate immune activation or dysregulation.
CD38: A multifunctional protein involved in cell activation and differentiation. CD38- B cells are typically less activated or belong to distinct B cell subsets.
Phenotype: CD21low CD38- B cells are often considered atypical or exhausted B cells, reflecting chronic immune activation or exposure to persistent antigens.

Clinical Significance of Activated CD21low CD38- %

Chronic Immune Activation:
- Elevated levels are associated with prolonged immune system activation, commonly seen in chronic infections such as:
  - HIV
  - Hepatitis B and C
  - Epstein-Barr Virus (EBV)
Autoimmune Diseases:
- Increased proportions of CD21low CD38- B cells are linked to autoimmune conditions, such as:
  - Systemic lupus erythematosus (SLE)
  - Rheumatoid arthritis (RA)
  - Sjögren’s syndrome
B Cell Exhaustion:
- Persistent antigen exposure, as seen in chronic infections or autoimmune diseases, can lead to the development of exhausted B cells, characterized by this phenotype.
Primary Immunodeficiencies:
- Abnormal levels may be observed in conditions affecting B cell development or function, such as:
  - Common variable immunodeficiency (CVID)
  - Specific antibody deficiency (SAD)
Cancer:
- Alterations in this subset have been noted in certain hematologic malignancies, such as B cell lymphomas or leukemias, particularly those involving dysregulated B cell activation.

Normal Ranges and Interpretation

The percentage of activated CD21low CD38- B cells can vary based on age, health status, and laboratory standards. In healthy individuals, this subset typically represents a small proportion of the total B cell population. Significant deviations from normal ranges require careful interpretation in the context of clinical findings and other laboratory markers.

Elevated Levels: May indicate chronic immune activation, autoimmune pathology, or B cell exhaustion.
Decreased Levels: Rarely observed but could suggest impaired B cell activation or production.

Evaluation and Diagnostic Approach

If activated CD21low CD38- % is abnormal, further evaluation should include:

Flow Cytometry Panel: To assess additional B cell markers and characterize the broader B cell profile.
Clinical Correlation: A thorough review of symptoms, medical history, and underlying conditions.
Additional Testing: Depending on suspected pathology, testing for autoimmune markers, chronic infections, or immunodeficiency conditions may be warranted.

Conclusion

The Activated CD21low CD38- % biomarker provides valuable insights into immune system status, particularly in the context of chronic activation, autoimmune diseases, or immune exhaustion. Its interpretation requires integration with clinical findings and other laboratory results to guide diagnosis and treatment strategies effectively.

Lab Results Explained and Tracked

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What does it mean if your Activated CD21 low CD38- % result is too high?

Elevated levels of Activated CD21low B cells signify chronic immune activation or dysregulation and are often associated with various pathological conditions. These cells, which comprise about 5% of B cells in the peripheral blood of healthy adults but are barely detectable in cord blood, can be further divided into CD38-24+ and CD38-24low subsets.

Key Implications of Elevated Levels:

Chronic Immune Activation:
- Persistent exposure to antigens, such as in chronic infections like HIV, hepatitis B or C, or Epstein-Barr virus (EBV), can lead to an expansion of these cells.
Autoimmune Diseases:
- Increased levels are frequently observed in autoimmune conditions such as:
  - Systemic lupus erythematosus (SLE)
  - Rheumatoid arthritis (RA)
  - Sjögren's syndrome
  - Axial spondyloarthritis
- In some autoimmune diseases like RA, CD21low B cells are predominantly naive B cells expressing unmutated IgM.
B Cell Exhaustion:
- Elevated CD21low B cells are considered exhausted or anergic B cells, often arising from prolonged antigen stimulation in conditions like chronic infections or autoimmune diseases.
Immunodeficiencies:
- In disorders such as common variable immunodeficiency (CVID) or other B cell dysfunctions, elevated levels may indicate compensatory activation in response to impaired immune responses.
Hematological Malignancies:
- Certain cancers, such as B cell lymphomas or leukemias, may show increased proportions of these atypical B cells due to dysregulated B cell activation.
- In chronic lymphocytic leukemia (CLL), low CD21 expression correlates with poor prognostic markers.

Phenotypic Characteristics of CD21low B Cells:

Higher expression of co-stimulatory molecules CD80 and CD86 compared to CD21+ counterparts.
Increased expression of CD11c, FCRL5, CD95, and ICAM-1.
Reduced expression of CD40.
Negative for CXCR5.

Clinical Implications:

Elevated Activated CD21low B cell levels highlight the need for further investigation into underlying causes, including autoimmune activity, chronic infections, or immune system dysfunction. These findings should be interpreted in the context of:

Clinical Symptoms
Medical History
Complementary Diagnostic Tests

Proper evaluation and correlation with other immune markers are essential for accurate diagnosis and treatment planning.

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Activated CD21 low CD38- %

Activated CD21low CD38- %

Understanding CD21low CD38- B Cells

Clinical Significance of Activated CD21low CD38- %

Normal Ranges and Interpretation

Evaluation and Diagnostic Approach

Conclusion

All Your Lab Results. One Simple Dashboard.

What does it mean if your Activated CD21 low CD38- % result is too high?

Key Implications of Elevated Levels:

Chronic Immune Activation:

Autoimmune Diseases:

B Cell Exhaustion:

Immunodeficiencies:

Hematological Malignancies:

Phenotypic Characteristics of CD21low B Cells:

Clinical Implications:

All Your Lab Results. One Simple Dashboard.

Import, Track, and Share Your Lab Results Easily

Import, Track, and Share Your Lab Results

Article Review & Sources

Bring All Your Lab Results Together — In One Place

Gather Your Lab History — and Finally Make Sense of It

Finally, Your Lab Results Organized and Clear

Advanced Plan

Unlimited Account

Pro Monthly

What's included in a Healthmatters membership

Import Lab Results from Any Source

See Your Health Timeline

Understand What Your Results Mean

Enter Your Lab Reports Yourself — Always Free Enter Your Lab Reports — Always Free

Visualize Your Results

Export Your Complete Lab History in a Single File Export Your Complete Lab History

Comprehensive Data Entry Service for Your Reports Data Entry Service for Your Reports

Securely Share With Anyone You Trust

Let Your Lab Results Tell the Full Story

Once your results are in one place, see the bigger picture — track trends over time, compare data side by side, export your full history, and share securely with anyone you trust.

Bring all your results together to compare, track progress, export your history, and share securely.

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All Your Lab Results.
One Simple Dashboard.

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