CD19+ B Cell CD27 and IgD Subtypes

This is an immunological blood test designed to assess B lymphocyte subpopulations according to their maturation and functional differentiation stages. The test is performed using flow cytometry, identifying CD19+ B cells and determining their subtypes based on CD27 and IgD markers.

This test allows for a more comprehensive evaluation of the state of humoral (antibody production-based) immunity.

What does this test show?

During the test, CD19+ B lymphocyte populations are analyzed based on CD27 and IgD expression:

• Naive B cells (CD27– IgD+) – cells of the "primary" immune system that have not yet encountered an antigen.
• Memory B cells (CD27+) – formed after contact with an antigen and responsible for a faster and stronger secondary immune response.
• Unswitched memory B cells (CD27+ IgD+) – early memory cells.
• Switched memory B cells (CD27+ IgD–) – more mature memory cells involved in the production of specific immunoglobulins (e.g., IgG, IgA).
• Double negative (CD27– IgD–) – a subpopulation that can increase under certain pathological conditions.

Results are presented as a percentage of all B lymphocytes (CD19+) and, if necessary, in absolute numbers.

When is the test recommended?

The test may be prescribed:

• When primary or secondary immunodeficiencies are suspected;
• In cases of decreased immunoglobulin levels in the blood;
• In cases of frequently recurring infections;
• To assess the effectiveness of vaccination;
• In autoimmune diseases;
• To monitor the effects of treatment with biological or immunosuppressive drugs.

How are the results evaluated?

Altered proportions of B cell subpopulations may indicate:

• Disturbed B cell maturation or differentiation;
• Decreased formation of immunological memory;
• Chronic immune stimulation;
• Immunodeficient condition.

Results are assessed considering the patient's age, clinical symptoms, and other laboratory test data. The final conclusion is provided by a physician who evaluates the overall clinical context.