A marker present on natural killer cells (NK) and T lymphocytes.
In cases of chronic diseases, including Lyme disease, the number of CD57 NK cells has been shown to be below normal.
Following treatment, the count can return to normal.
The utility of this test is controversial (Marques et. al) reported that there was no difference between the CD57 NK cell counts among patients with Lyme disease and normal controls.
This test measures only the CD57 NK cells and may be useful for patients with known Lyme disease who present with chronic symptoms.
If the count is low, the cause of the symptoms may be from Borrelia burgdorferi.
If the count is normal, the cause may still be from Lyme disease, but it could also be due to some other agent.
Reference Range CD57 NK Cells (Absolute Count/l) <40 LOW
40 to 98 BORDERLINE
98 NORMAL
The CD57 is expressed on both natural killer (NK) cells and T lymphocytes.
The CD57 test measures CD57 positive NK cells only.
The test is performed on EDTA whole blood.
In patients with low CD 57 counts, Lyme disease and Chlamydophila pneumoniae infections should be included in differential diagnosis.
If laboratory tests are positive for Lyme disease in a chronically ill patient, this test can be useful prior to antimicrobial therapy to suggest that the cause of the symptoms is due to Lyme disease.
If the count is low, repeat testing after therapy can also be useful.