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T-cell activation markers

Category Immunology
Test background

This is a flow cytometric assay used to quantify the percentage of T- cells (CD3+/CD4+ and CD3+/CD8+ cells) expressing the activation markers CD25 and HLA-DR. This test is currently only available to the National HTLV-1 service.

HTLV-1 is a CD4 tropic retrovirus that is asymptomatic in around 90% of patients. In the UK an estimated 22,000 people are infected. Around 2-5% of HTLV-1 infected patients will have malignant transformation to adult T cell leukaemia/lymphoma (ATLL) and up to 3% of infected patients develop a progressive disease of the nervous system (HAM/TSP, HTLV-1 associated myelopathy/tropical spastic paraparesis).

Serial monitoring of the CD4+CD25+ population in HTLV-1 patients may aid in predicting disease progression.

Clinical Indications

Monitoring HTLV-1 infection

Reference range
T cell activation subsets Ranges (%)
CD3+CD4+CD25+ 15.7- 34.9
CD3+CD4+HLADR+ 4.2 – 13.9
CD3+CD8+CD25+ 4.6 – 10.9
CD3+CD8+HLADR+ 5.7 – 38.2

Ranges validated in house


Sample & container required 3ml blood (EDTA lavender top)
Do not separate or refrigerate, must be processed within 48 hours
Sample volume 3 mL
Turnaround time 3 days