CD4 Count

Excerpt

CD4 count is a laboratory test that measures CD-4 T lymphocytes (T cells) via flow cytometry. This test is an important parameter in HIV management and is used to guide clinical treatment. The CD4 count is a reliable indicator of a patient’s immunologic status and is used to determine the necessity for initiation of prophylactic treatment against opportunistic infections.

CD4 T cells are human helper T cells that express cluster determinant 4 (CD4) molecules. The CD4 molecule is a member of the immunoglobulin family and primarily mediates adhesion to major histocompatibility complex molecules. CD4 T cells are selectively targeted and infected by HIV. HIV proliferates rapidly during acute infection leading to high levels of viremia and rapid impairment and death of CD4 T cells.