What is tdt positive cells?

TDT-positive cells are cells that express the enzyme terminal deoxynucleotidyl transferase (TDT), which catalyzes the addition of nucleotides onto the 3' ends of DNA during V(D)J recombination. This process occurs during the development of lymphocytes, when they undergo gene rearrangements to generate diverse antigen receptors.

TDT-positive cells are typically found in the thymus, bone marrow, and other lymphoid organs during periods of active lymphocyte development. TDT-positive cells are considered to be immature lymphocytes that have not yet undergone the full process of differentiation.

TDT expression can also be seen in certain types of leukemia and lymphoma, making it a useful marker in the diagnosis and monitoring of these conditions. TDT-positive leukemias are typically indicative of an early stage of lymphocyte development, and are more common in pediatric patients.