CD4 TEST:
Why CD4 Test?
CLINICAL INFORMATION
The main purpose of the CD4 test is to count CD4 cells to check the health of the immune system in people with immuno-compromised conditions such as HIV etc, where CD4 cells are destroyed and very low levels make the immune system weak to fight against infections. Hence CD4 tests are performed in conjunction with HIV viral load test and moreover, the outcome of treatment (prognosis) like antiretroviral treatment (ART or AVT) or sometimes highly active antiretroviral therapy (HAART), lymphomas, and organ transplant, checks the CD4 count to see if these levels are increased or decreased or stabilized. In our human system, there are two types of lymphocytes namely T cells and B cells are synthesized in the bone marrow. B cells remain in the bone marrow for maturation while the T cells move to the thymus to mature, hence they are called T- Lymphocytes or T cells (thymus-derived lymphocytes) and B-lymphocytes or B cells (bone marrow-derived lymphocytes). T cells respond to viral infections and boost the immune function of other cells (T cells coordinate the activities of other cells in the immune system that fight viruses, bacteria, and cancers), while B cells fight bacterial infections. Abnormal T and B cells reflect altered immune function or disease like infection or disorders of the immune system. These lymphocyte subtypes are recognized by cell surface markers or antigens such as CD3, CD4, CD8 (CD means cluster of differentiation, a glycoprotein that serves as a co-receptor for the T-Cell Receptor –TCR. The CD numbers identifies the specific subtype of immune cells), etc. T 4 or CD4 or Helper T cells coordinate the activity of other immune cells. CD 8 cells or Killer T-cells, recognize and destroy abnormal cells such as cancer cells and cells infected with a virus, and CD 8 or Suppressor T cells limit the activity of other immune cells so they do not harm normal tissues. CD4 in T4 is a type-1 transmembrane glycoprotein and member of the immunoglobulin superfamily. Primarily described as a marker for T cell subsets it can also be found on NKT cells, innate lymphoid cells, and macrophages.
CD4 forms as a part of the T cell receptor complex that binds to the beta 2 domain of the MHC molecule leading to activation of pathways downstream of the T cell receptor. CD4 acts as a facilitator of the interaction between the T cell receptor and the MCH/antigen complex on antigen-presenting cells. This interaction subsequently leads to T cell activation and also forms the basis of some T cell therapies against cancer. CD4 is also a receptor for IL6 and a co-receptor for HIV and human herpes 7.
General Instructions:
Sample Requirement: Specimen - Blood sample collected from the vein. Test Preparation: None.
NOTE - Sample for specimen collections may vary based on the patient’s condition/cases according to the patient’s presenting complaints/signs or symptoms:
SPECIMEN REQUIREMENT (Special or Rare Cases) - As instructed and guided by Physician / Clinician / Pathologist / as per Laboratory’s requirements, according to procedures and protocols.
Sample Requirement: Blood Sample taken from the vein
Test Preparation: Suggestions from your Doctor
This Multi-Specialty Clinical Referral Laboratory RT DIAGNOSTICS provides precise and accurate tests with an extensive range of testing services to the medical centers to help in the diagnosis and identification of pathology in the test specimens for infectious diseases and also to evaluate the function of organ systems of the patient. It prevents further complications and helps to stabilize and restore health to near normalcy at the earliest without delay.
