A micromethod for determination of terminal deoxynucleotidyl transferase (TdT) in the diagnostic evaluation of acute leukemias

M. J. Modak, R. Mertelsmann, B. Koziner, R. Pahwa, M. A.S. Moore, B. D. Clarkson, R. A. Good

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


A micromethod for the determination of TdT in peripheral leukocytes and bone marrow cells has been developed that allows unequivocal identification and quantitation of TdT in less than 1 x 106 leukocytes from ALL patients, i.e., in 1 ml of peripheral blood and/or 0.5 ml of bone marrow obtained during routine clinical sampling. The method involves disruption of cell pellet with high salt and detergent followed by centrifugation of extracts at 12,000 x g and partial purification on phosphocellulose matrix by a batch elution technique using a standard laboratory microcentrifuge. Using this microassay, TdT activities have been determined in 500 samples of peripheral blood and bone marrow of 240 adult patients with acute leukemias (86 ALL, 108 ANLL, 44 blastic CML, two acute leukemias following P. vera). From an analysis of our data based on TdT activity, cell surface markers and growth patterns in soft agar and observations published in the literature, it can be concluded that the frequencies of TdT + phenotypes in the various clinicalmorphological diagnostic groups are approximately 95% in ALL, 10% in ANLL, 50% in AUL, and 35% in blastic CML. Since the presence of high TdT activity is clearly associated with clinical response to specific forms of chemotherapy in blastic CML and most probably, also in ANLL, the determination of TdT should be considered in all cases of acute leukemias to objectively define prognostically important subgroups which can not be diagnosed by conventional means.

Original languageEnglish (US)
Pages (from-to)91-104
Number of pages14
JournalJournal of cancer research and clinical oncology
Issue number1
StatePublished - Oct 1 1980


  • Acute leukemia
  • TdT micromethod

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


Dive into the research topics of 'A micromethod for determination of terminal deoxynucleotidyl transferase (TdT) in the diagnostic evaluation of acute leukemias'. Together they form a unique fingerprint.

Cite this