Evaluation of methods of detecting terminal deoxynucleotidyl transferase in human hematologic malignancies. Comparison of immunofluorescence and enzymatic assays.
Terminal transferase (TdT) activity and antigen have been measured in 267 specimens of human bone marrow and peripheral blood by using a biochemical assay for enzymatic activity and an immunofluorescence test for antigen. Oligo p(dA)50 and dGTP were used as reagents in the biochemical assay and either rabbit anti-calf TdT or rabbit anti-human TdT was used as the primary antibody for immunofluorescence. Because both false-positive and false-negative detection of TdT antigen occurs, the biochemical assay of TdT activity is considered the standard against which immunofluorescence assays must be measured. If specimens of cells contained TdT activity, then the immunofluorescence detected antigen in 91% of cases (rabbit anti-calf TdT) and 95% of cases (rabbit anti-human TdT). When no TdT activity was detected, the immunofluorescence test was positive in 7.8% of cases (rabbit anti-calf TdT) and 5.2% of cases (rabbit anti-human TdT). When air-dried slices were shipped by air mail to a distant location before being stained for immunofluorescence, TdT antigen was detected in only 33% of matched pair cases which contained TdT activity. From this study, the authors conclude that with current methodology, immunofluorescence tests for TdT antigen must be carried out on slides prepared in the testing laboratory and that such tests are reliable in more than 90% of cases. However, because a small percentage of results are false positives and false negatives, the authors suggest that if a patient's clinical response is not consistent with the immunofluorescence TdT result, an enzymatic assay for TdT activity be carried out.
D000941:Antigens / Q000032:analysis; D001853:Bone Marrow / Q000201:enzymology; D004253:DNA Nucleotidylexotransferase / Q000032:analysis* / Q000097:blood / Q000276:immunology; D004254:DNA Nucleotidyltransferases / Q000032:analysis*; D003848:Deoxyguanine Nucleotides; D005069:Evaluation Studies as Topic; D005455:Fluorescent Antibody Technique; D006801:Humans; D007938:Leukemia / Q000201:enzymology*; D008223:Lymphoma / Q000201:enzymology*; D009838:Oligodeoxyribonucleotides; D013048:Specimen Handling; D014316:Tritium
D000941:Antigens; D003848:Deoxyguanine Nucleotides; D009838:Oligodeoxyribonucleotides; C030570:oligodeoxyadenylic acid; D014316:Tritium; C029603:deoxyguanosine triphosphate; D004254:DNA Nucleotidyltransferases; D004253:DNA Nucleotidylexotransferase