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Two consecutive immunophenotypic switches in a child with immunogenotypically stable acute leukaemia
Author(s) -
Bierings M.,
Szczepański T.,
Van Wering E. R.,
Willemse M. J.,
Langerak A. W.,
Révész T.,
Van Dongen J. J. M.
Publication year - 2001
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.1365-2141.2001.02772.x
Subject(s) - immunophenotyping , clone (java method) , gene rearrangement , cd33 , myeloid , bone marrow , medicine , immunology , acute lymphocytic leukemia , cancer research , pathology , leukemia , biology , stem cell , gene , cd34 , genetics , antigen , lymphoblastic leukemia
A 12‐year‐old girl presented with a CD33 + precursor B‐acute lymphoblastic leukaemia (ALL) and seemed to respond well to ALL treatment. However, 2 weeks after diagnosis her leucocyte count rose rapidly with a predominance of myeloid blasts with M5b morphology and CD19 + myeloid immunophenotype. Acute myeloid leukaemia (AML) treatment was started and remission was achieved after one course of chemotherapy; the AML treatment was continued for 6 months. Two months after cessation of chemotherapy, the patient developed a bone marrow relapse, this time with an undifferentiated blast morphology and a precursor B immunophenotype. Molecular analysis of the immunoglobulin and T‐cell receptor genes showed several clonal gene rearrangements at diagnosis: two IGH , two IGK and two TCRD gene rearrangements. All rearrangements were also detected during the AML phase of the disease, suggesting a phenotypic shift of the same leukaemia. At relapse, 8 months later, all rearrangements were preserved except for one TCRD (Vδ2–Dδ3) rearrangement. The first phenotypic shift in the genotypically stable leukaemia was remarkably fast. The most probable explanation for our observations is an oncogenic event in an undifferentiated haematopoetic progenitor clone, with a highly versatile phenotype.