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Medline ® Abstract for Reference 97

of 'Clinical manifestations, pathologic features, and diagnosis of T cell large granular lymphocyte leukemia'

97
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Mono/oligoclonal T and NK cells are common in chronic myeloid leukemia patients at diagnosis and expand during dasatinib therapy.
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Kreutzman A, Juvonen V, Kairisto V, Ekblom M, Stenke L, Seggewiss R, Porkka K, Mustjoki S
SO
Blood. 2010;116(5):772. Epub 2010 Apr 22.
 
In a proportion of patients with chronic myeloid leukemia (CML) being treated with dasatinib, we recently observed large granular lymphocyte (LGL) expansions carrying clonal T-cell receptor (TCR) gamma/delta gene rearrangements. To assess the prevalence and role of clonal lymphocytes in CML, we collected samples from patients (n = 34) at the time of diagnosis and during imatinib and dasatinib therapies and analyzed lymphocyte clonality with a sensitive polymerase chain reaction-based method of TCR gamma and delta genes. Surprisingly, at CML diagnosis, 15 of 18 patients (83%) had a sizeable clonal, BCR-ABL1 negative lymphocyte population, which was uncommon in healthy persons (1 of 12; 8%). The same clone persisted at low levels in most imatinib-treated patients. In contrast, in a distinct population of dasatinib-treated patients, the diagnostic phase clone markedly expanded, resulting in absolute lymphocytosis in blood. Most patients with LGL expansions (90%) had TCR delta rearrangements, which were uncommon in patients without an LGL expansion (10%). The TCR delta clones were confined to gammadelta(+) T- or natural killer-cell compartments and the TCR gamma clones to CD4(+)/CD8(+) alphabeta(+) fractions. The functional importance of clonal lymphocytes as a part of leukemia immune surveillance and the putative anergy-reversing role of dasatinib require further evaluation.
AD
Hematology Research Unit, Biomedicum Helsinki, Helsinki University Central Hospital (HUCH), Helsinki, Finland.
PMID