CD3

CD3 is a multimeric protein complex on the surface of T lymphocytes. Its non-covalent binding to T cell receptor (TCR) can stabilize TCR structure and transmit activation information, ensuring the normal operation of T cell antigen recognition and signal transduction. In clinical practice, CD3 can be used as a diagnostic biomarker for various tumors such as anaplastic large cell lymphoma, angioimmunoblastic T cell lymphoma, and extranodal NK/T-cell lymphoma. Meanwhile, the combination of CD2, CD3, CD5, and CD7 has reference significance for differentiating between reactive lymphoid hyperplasia (RLH) and peripheral T cell lymphoma (PTCL), which is because they are fully expressed in RLH but partially or completely absent in PTCL. Moreover, CD3 and CD20 co-expressed T cells were found in some large cell lymphomas, speculated that they are related to the pathogenesis of PTCL. In addition, some scholars suggested that multiple myeloma patients with CD3+ T lymph nodes and an increased proportion of CD3+ T cells have better prognosis.