CDR3 SIZE ANALYSIS OF T-CELL RECEPTOR-V-BETA TRANSCRIPTS - FOLLOW-UP-STUDY IN A PATIENT WITH T-CELL ACUTE LYMPHOBLASTIC-LEUKEMIA

T cell acute lymphoblastic leukemia (T-ALL) is generally considered to be a clonal disorder arising as an expansion of committed lymphoid pr ecursors. The generation of functional T cell receptor (TCR) genes inv olves DNA rearrangement processes. This predisposes immature lymphoid cells to abnormal rearrangements. Previous analysis of the TCR genes s trongly suggested the clonal origin of human T-ALL. We present a sensi tive clonal analysis of bone marrow TCR V beta transcripts in a case o f T-ALL. This study allows the analysis not only of TCR V beta transcr ipts in tumor cells but also the temporal modification of the global T CR repertoire in the follow-up of clinical specimens from bone marrow aspirates. Moreover, we used clone-specific junctional region oligonuc leotide probes corresponding to the clonal leukemic population for the molecular monitoring of the malignant clone throughout the clinical c ourse of the disease. This molecular fingerprint appears to be a sensi tive method to detect minimal residual disease. It shows that junction al regions of rearranged TCR beta genes corresponding to the tumor cel ls can also he detected at the time of the complete remission.