Reference Work Entry

Encyclopedia of Public Health

pp 104-104



CD4 is a protein, which can be found on the surface of various cells, among others T-lymphocytes (T4-cells, helper T-cells). By binding to the CD4-molecules, HI-viruses can pass into the cells. CD4-test determines the amount of helper T-cells. The CD4-value is reverse proportionally to the impairment of the immune system, this means, the lower the level is, the more immunodeficiency has progressed. Normal values for CD4 are 600–1000 cells/pl.

In HIV-infections the graduation into the CD4-helper status 1 to 3 depends on the CD4-value: Status 1 means a value of 500 cells/pl, status 2 is reached when the value is 200–400 cells/pl, in status 3 CD4-count is below 200 cells/pl.

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