Lymphocyte Subsets

Distinct lymphocyte subsets including T-cells, B-cells, and natural killer (NK) cells are identifiable by characteristic cell surface marker molecules. T-cells are involved in cell mediated immunity, B-cells with humoural immunity and NK cells play a role in defence against viral infections and tumours. T-cells are CD3 positive, B-cells are CD19 positive, and NK cells are CD3 negative, CD16 and CD56 positive. T-cells are further classified as helper cells (CD4 positive,) or cytotoxic cells (CD8 positive,). In turn, CD4+ and CD8+ cells can be classified as naïve (CD4RA+, CD8RA+) or memory cells (CD4RO+, CD8RO+).

The absolute number and percentage of different lymphocyte subsets can vary in various diseases. For example, in individuals with human immunodeficiency virus (HIV) infection, the number of CD4+ cells and the CD4+: CD8+ ratio is affected by the stage of disease and response to treatment. Thus, lymphocyte subset analysis can provide information regarding the immune status of the HIV infected patient and assist in monitoring therapy. Characteristic lymphocyte subset profile can be seen in a number of primary immunodeficiency disorders. A specific test request for T-cell subsets only test for CD4 and CD8 lymphocytes and is used for monitoring anti-retroviral treatment and HIV infection.
Reference range: 

Lymphocytes CD 3 %, 55 - 83
Lymphocytes CD 3 absolute counts, 700 - 2100
Lymphycytes CD 4 %, 28 - 57
Lymphocytes CD 4 absolute counts, 300 - 1400
Lymphocytes CD 8 %, 10 - 39
Lymphocytes CD 8 absolute counts, 200 - 900
B cells CD19 %, 6 - 9
B cells absolute counts, 100 - 500
NK cells %, 7 - 31
NK cells absolute counts, 90 - 600

Absolute counts, cells / µL Percentages are as shown
Sample type and Volume required: 
EDTA whole blood 4.0 ml.
Turnaround time: 
All samples will be analysed on the day of arrival or the following day if this does not exceed the 24-hour limit.
Special sample instructions: 

All tests are compromised by prolonged transit times. For this reason, date of bleed and date of postage must be provided with each request.

Storage and transport: 
Samples must NOT be refrigerated. Please state time of venesection on the request form. Samples are suitable for analysis up to 24 hours post venesection. Samples that arrive in lab after 24 hours will not be analysed. Courier transport is recommended on the day of venesection.
Time limit for extra tests: 
*NO* tests can be added at any time
Diagnostic Immunology and Allergy Department at King's College Hospital
General Enquiry : 020 3299 8752 / 020 3299 1171
King's College Hospital
Bessemer Wing - 1st Floor
Denmark Hill
London SE5 9RS
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 03/11/2021