CD7 expression by CD34⁺ cells in CML patients, of prognostic significance?

Abstract

The purpose of the study was to identify a unique immunophenotype of normal or Philadelphia chromosome positive (Ph+) CD34+ cells that might be used to purify normal CD34+ cells from chronic myelogenous leukemia (CML) patients. An immunophenotypical study of CD34+ bone marrow cells of 20 patients with CML at diagnosis and during hydroxyurea treatment, and 39 controls were performed. All patients were Ph+, two patients had variant translocations and three patients displayed cytogenetic signs of clonal evolution. The immature progenitor cell compartment (CD34+ HLA-DR- and CD34+ CD38- cells) was comparable. The CD34+ AC133+ progenitor cell compartment was decreased in CML patients. We found no difference for any of the adhesion molecules examined except for CD62L, where the percentage of CD34+ CD62L+ cells was decreased in CML patients. The number of myeloid progenitors (CD34+ CD33+) was increased at the expense of B-lymphoid progenitors (CD34+ CD10+ and CD34+ CD19+) in CML patients indicating that B-lymphopoiesis is inhibited in CML. The megakaryocytic (CD34+ CD61+) and erythroid (CD34+ CD71+) progenitors were increased in CML patients. The number of CD34+ CD7+ cells was also significantly increased (mean 25.3% vs. 4.9%). However, the level of CD7 expression was quite heterogeneous, and the patients could be separated into two populations according to CD7 expression (more or less than 20% CD7+ CD34+ cells). The Sokal and Hasford risk scores did not differ between CD34+ CD7- CML and CD34+ CD7+ CML, but all patients with signs of disease progression clustered in the CD34+ CD7+ population indicating that the level of CD7 expression on CD34+ cells may be of prognostic importance in CML.

Homoharringtonine Combined with Cytarabine to Treat Chronic Myelogenous Leukemia in Myeloid Blast Crisis and Its Impact on Bone Marrow CD34+CD7+ Cells

“…It has shown that chromosomal anomalies in addition to the Ph chromosome are more commonly detected in the CD34+CD7+ Ph+ subset of CML cells than in the CD34+CD7- Ph+ subset, and patients with high levels of CD7 in CD34+ cells at diagnosis had a poor prognosis. Therefore, the level of CD7 in CD34+ cells at diagnosis has been considered an important prognostic marker for CML [14,15,16,19,20]. …”

“…Theoretically, HHT combined with Ara-C (HA regimen) should be potentially synergistic in eliminating both bulk leukemic cells and leukemic progenitors or stem cells in CML-MBC. In the present study, 34 patients with CML-MBC were treated with the HA regimen and its effect on bone marrow CD34+CD7+ cells, an important subpopulation of progenitor cells in CML-MBC [12,13,14,15,16], was analyzed among other clinical and homological parameters.…”

High expression of CD7 on CD34+cells is not linked to deletion of derivative chromosome 9 or lack of dendritic cells in chronic myeloid leukaemia

“…The Sokal score has also been successful in predicting survival in patients treated with hydroxyurea and, more recently, imatinib [5,6]. We and others have reported an increased expression of CD7 on CD34 + cells in some patients with CML [7][8][9], and high expression of CD7 confers an adverse prognosis which is independent of Sokal and Hasford scores [7,8]. In normal individuals, 4-5 % of CD34 + bone marrow cells express CD7 [10,11].…”

“…In normal individuals, 4-5 % of CD34 + bone marrow cells express CD7 [10,11]. Our previous study showed that, using a cut-off of 20 %, CML patients could be divided into two groups according to the level of expression of CD7 on their CD34 + bone marrow cells, and patients with w20 % CD34 + CD7 + cells had a significantly worse outcome than patients with v20 % CD34 + CD7 + cells [7]. Yong et al confirmed our results using molecular profiling of CD34 + cells procured by leukapheresis at diagnosis [8].…”

Effect of homoharringtonine on bone morrow CD34+CD7+ cells in chronic granulocytic leukemia

“…It is also an independence prognostic factor and one of the important target for treatment [1][2][3] . It has been confirmed that about 1/3 CGL patients in chronic phase can get cytogenetic response with the treatment of homoharringtonine (HHT) alone [4][5][6][7] , but the mechanism needs further research.…”