Evaluation of marrow and blood haemopoietic progenitors in chronic lymphocytic leukaemia before and after chemotherapy

Abstract

We have evaluated the number and differentiation pattern of CD34+ cells, as well as the CFU–GM, BFU–E and CFU–GEMM progenitors from the blood (PB) and marrow (BM) of 53 chronic lymphocytic leukaemia (CLL) patients. Twenty‐four patients were untreated and 29 were studied at 2 months from the last course of fludarabine or chlorambucil; 6 patients, studied after fludarabine therapy, were further evaluated after mobilization with cyclophosphamide and G–CSF. PB of untreated patients showed a median number of CD34+ cells, CFU–GM, BFU–E and CFU–GEMM/105 seeded cells and per litre of PB similar to those of normal controls. No differences were also found in the number of clonogenic progenitors/105 cells in patients studied before and after therapy, while significantly fewer BFU–E/l of PB were found after fludarabine. The number of circulating CD34+ cells/l of PB was significantly lower in patients treated with fludarabine or chlorambucil compared to untreated patients. BM growth was significantly reduced in untreated CLL patients compared to healthy donors. Treatment with fludarabine or chlorambucil restored BM progenitors at levels similar to those of normal controls; this effect did not occur for CFU–GM in patients treated with fludarabine. Three‐colour fluorescence analysis demonstrated a differentiation pattern of CD34+ cells, with a greater expression of CD13 and CD33 after treatment with fludarabine compared to untreated patients and normal controls. In 4 patients previously treated with fludarabine who underwent a successful cyclophosphamide and G‐CSF mobilization therapy, 4 × 106 CD34+ cells/kg were collected. These 4 patients showed a notable increase of CD34+ cells and of clonogenic cells in the PB, but a marked decrease of BM progenitor cells. The 2 patients who failed CD34+ cell mobilization had a reduced CFU‐GM growth both in the PB and in the BM. Taken together, these studies indicate that residual haemopoietic progenitors are present in untreated CLL patients and that stem cell mobilization and collection can be carried out following fludarabine treatment.

Disease-Related Anemia in Chronic Lymphocytic Leukemia Is Not Due to Intrinsic Defects of Erythroid Precursors: A Possible Pathogenetic Role for Tumor Necrosis Factor-Alpha

“…Moreover, both CLL patient subgroups had significantly fewer CD34+ cells, compared to healthy volunteers. On the contrary, Sala et al [23] reported similar percentages of CD34+ cells both in PB and BM of untreated CLL patients, compared to healthy controls. In conclusion, the degree of BM lymphocytic infiltration may play a role, but cannot adequately explain the development of disease-related anemia in all CLL patients.…”

“…In our study, using a clonogenic assay in methylcellulose medium and a liquid culture system, we have demonstrated that CD34+ cells can be effectively differentiated into more mature erythroid cells, in the presence of the suitable growth factors. Other investigators have reported their experience in the clonogenic capacity of the total BM mononuclear fraction [23, 26], but not of purified marrow CD34+ cells, postulating that fewer BFU-E colonies were risen, compared to healthy volunteers. In these studies, the presence or absence of anemia and the role of the extent of BM lymphocytic infiltration have not been analyzed.…”

Structure and function of the hematopoietic cancer niche focus on chronic lymphocytic leukemia

“…Normal CD34 + hematopoietic stem cells have to compete with CLL cells for CXCL12 elaborated by marrow stroma. As a likely consequence, patients with CLL may come to have a reduced number of CD34 + stem cells that can give rise to granulocytes/ macrophages, megakaryocytes, and erythrocytes in the marrow, compared to healthy individuals (16).…”

Chronic lymphocytic leukemia

“…Whether this is due to a greater degree of immune incompetence in patients with CLL or is secondary to the immunosuppressive effects of fl udarabine and other therapy is unknown. It is not always possible to collect enough CD34+ cells, especially in heavily pretreated patients, 49 and an interval of at least 3 months should be allowed between the last dose of fl udarabine and stem cell collection. This suggests that selected patients should be transplanted as soon as treatment is indicated and perhaps even, for selected patients, as consolidation therapy of a fi rst complete or partial remission.…”