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Acute myeloid and T‐cell acute lymphoblastic leukaemia with aberrant antigen expression exhibit similar TCRδ gene rearrangements
Author(s) -
Schmidt C. A.,
Przybylski G.,
Tietze A.,
Oettle H.,
Siegert W.,
Ludwig W. D.
Publication year - 1996
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.1996.426964.x
Subject(s) - terminal deoxynucleotidyl transferase , t cell receptor , myeloid , biology , microbiology and biotechnology , gene rearrangement , t cell , antigen , gene , immunology , genetics , apoptosis , tunel assay , immune system
TCRδ gene recombination patterns were analysed by Southern blot, polymerase chain reaction and nucleotide sequencing in acute myeloid leukaemias with coexpression of lymphoid antigens (Ly + AML, n = 10) as well as in early T‐cell acute lymphoblastic leukaemias with (My + T‐ALL, n = 10) and without coexpression of myeloid antigens (My − T‐ALL, n = 9). These 29 acute leukaemias exhibiting TCRδ gene rearrangements were selected from 66 Ly + AML, 14 My + T‐ ALL and 12 My − T‐ALL cases. Similar recombination patterns, namely Dδ2Jδ1 and Vδ1Jδ1 gene rearrangements, were observed in Ly + AML and My + T‐ALL. In contrast to Vδ2Dδ3 rearrangements in B‐cell precursor ALL, these rearrangements require activation of a T‐cell‐specific TCRδ enhancer. Comparison of My + T‐ALL and Ly + AML with My − T‐ALL exhibited a higher incidence of incomplete Dδ2Jδ1 rearrangements in My + T‐ALL and Ly + AML. Since a Dδ2Jδ1 rearrangement is an early event in TCRδ recombination, these leukaemias seem to be arrested at an earlier stage of differentiation. Similar patterns of TCRδ rearrangements in My + T‐ALL and Ly + AML suggest existence of a common myeloid/T‐lymphoid progenitor cell. Although weak or missing expression of terminal deoxynucleotidyl transferase (TδT) was found in 7/10 Ly + AML cases, no difference was observed in numbers of N‐nucleotides inserted in junctional regions when comparing with 3/10 cases exhibiting TdT expression. Since TdT activity is necessary for N‐nucleotide addition, this finding suggests down‐regulation of TδT expression after rearrangement took place in these Ly + AML cases.