CD4
MIM.186940 12pter-p12
CD4 is a non-polymorphous glycoproteins belonging to immunoglobulin superfamily. It is expressed on surface of T helper cells and serves as co-receptor in MHC class II-restricted antigen induced T cell activation. CD4 is homologous to CD223
Pathology
CD4+ CD25+ T cells maintain peripheral tolerance and prevent autoimmunity.
AIDS - HIV infection
- CD4 serves as HIV receptor on T cells, macrophages, brain.
- CD4 is downregulated by HIV Nef protein during AIDS progression.
- Normally CD4 > CD8; in HIV patients, CD4/CD8 ratio is inverted (i.e. CD4 < CD8) and patients are at risk for opportunistic infections
Expression in tumors
many post-thymic T cell leukemia/lymphomas
indolent T cell lymphoblastic proliferation
pityriasis lichenoides
CD4+ CD56+ hematodermic malignancies (blastic NK lymphoma)
histiocytic lymphoma / histiocytic sarcoma
acute myeloid leukemia
some pyothorax associated lymphomas
cutaneous lymphomatoid granulomatosis
lymphomatoid papulosis
florid antiviral inflammatory response
Negative immunostaining
NK cells
T cell lymphoma with cytotoxic phenotype
hepatosplenic alpha/beta and gamma/delta lymphoma
enteropathy associated T cell lymphoma
B cell lymphoma
Hodgkin lymphoma
nonhematopoietic neoplasms
See also
CDs