Hematological recovery after autologous bone marrow transplantation in acute leukemia: predictive factors

The criteria for bone marrow recovery post-myelosuppressive therapy for acute myelogenous leukemia: a quantitative study

CONTEXT

Although the early post-myelosuppressive chemotherapy pathologic changes of the marrow have been described, the rate and the histologic definition of recovery are not defined.

OBJECTIVE

To study the rate of recovery of bone marrow in patients given myelosuppressive therapy for acute myelogenous leukemia, establish the histologic criteria of recovered marrow, and correlate the recovery pattern with those patients who received a bone marrow transplant by using histology, peripheral blood, immunophenotyping, and computerized morphometry and mathematical slope equation.

DESIGN

We studied the post-myelosuppression recovery of the bone marrow to determine patterns and rate of recovery in 135 serial bone marrow biopsies of 51 patients. These patients were divided into 2 groups: 1 group of 28 cases diagnosed with acute myeloid leukemia, the majority treated with cytarabine (Ara-C) infusion for 7 days and daunorubicin intravenously daily for 3 days (7+3 regimen), and the other control group of 23 cases treated with chemotherapy or allogeneic bone marrow transplantation for a variety of hematologic malignancies. All biopsies during the recovery period were obtained before consolidation regimen. We used morphometry to calculate the cellularity and myeloid to erythroid ratio and quantified megakaryocytes CD10 versus time from day 14 onward. The absolute neutrophil and platelet counts for 28 cases were related to histologic recovery.

RESULTS

From day 14, we noted a differential slope of recovery of these patients with no difference in male and female patients, P = .45, but a difference between younger and older patients (>58.5 years), P = .03. After regenerative hyperplasia, the cellularity plateaus, the myeloid to erythroid ratio, and the megakaryocytes even out with platelet normalization, and the early CD10+ B cells rise from day 40 onward, P = .01. The patterns of recovery after day 60 of postchemotherapy and posttransplantation patients are similar. Complete histologic and peripheral blood recovery is noted at day 38 and thereafter.

CONCLUSIONS

By linear equation using at least 2 trephine biopsy specimens, the projected rate of cellular recovery may be determined, and 5 histologic features are associated with complete histologic recovery.

Reduced total number of cobblestone area forming cells and in vitro stromal-cell growth in autografts from acute myeloid leukemia patients

BACKGROUND

It is well known that ABMT in acute myeloid leukemia (AML) often results in delayed hematopoietic engraftment, but the reason behind this has not been resolved. Previous studies have largely dealt with measurements of committed myeloid progenitors as surrogate markers for hematopoiesis.

METHODS

Measurements of Week 5 cobblestone area forming cells (CAFC) and stromal-cell growth in BM autografts from 14 AML patients were compared with those from 10 NHL patients.

RESULTS

Grafts achieved from the AML patients contained a significantly lower total number of CAFC than those from the NHL patients. The reason for this was a lower total amount of mononuclear cells (MNC) obtained during harvest procedure (mean 0.4 x 10(8)/kg for AML, versus 0.8 x 10(8)/kg for NHL). In contrast, the frequency of CAFC was comparable both between patient groups (mean 1.47, range 0.15-6.33 per 10(4) MNC for AML versus mean 1.47, range 0.53-3.57 per 10(4) MNC for NHL) and compared with that of eight normal donors (mean 1.12, range 0.73-1.73 per 10(4) MNC). An inverse relationship was observed between the total CAFC number in the grafts and the hematopoietic reconstitution of both granulocytes > or = 2.0 x 10(9)/L and thrombocytes > or = 50 x 10(9)/L, in which the level of 9.0 x 10(3) CAFC/kg implied a prompt engraftment for both patient groups. Whereas the stromal cell outgrowth in vitro from 8/10 NHL patients was similar to that of six normal donors, only a few stromal cells appeared in the majority of nine evaluable AML patients.

DISCUSSION

A decreased total CAFC content, as well as an inferior stromal-cell function, may be critical elements for prolonged hematopoietic reconstitution in AML.

Stroma-supported progenitor production as a prognostic tool for graft failure following autologous stem cell transplantation

To analyse the involvement of a possible numerical or qualitative stem cell defect in the development of sustained graft failure after autologous transplantation, we have determined the graft content of CD34+ nucleated cells, colony-forming cells and cobblestone area-forming cell subsets, as well as transplant ability to produce progenitors using the long-term culture colony-forming cell (LTC-CFC) assay. We evaluated material from the graft reference ampoules of 13 graft failure patients after bone marrow transplantation (BMT), four graft failure patients and four isolated thrombocytopenia patients after peripheral blood stem cell transplantation (PBSCT). We compared these data with those from six successfully engrafted BMT patients and 20 engrafted PBSCT patients respectively. In the BMT setting, the LTC-CFC 6-week assay represented a highly significant graft failure predictor. In the PBSCT setting, the total number of 2-week and 6-week LTC-CFCs transplanted per kg bodyweight (BW) showed the highest significant difference between the engrafted and the graft failure patients, as well as between the engrafted patients and the patients suffering from isolated thrombocytopenia after transplantation. These data show that the ability of a graft to generate progenitors in vitro rather than the number of primitive progenitors transplanted can have prognostic value for post-transplant haematological reconstitution.

Long-term cryopreservation: successful trilineage engraftment after autologous bone marrow transplantation with bone marrow cryopreserved for seven years

Successful autologous bone marrow transplantation (ABMT) and peripheral blood stem cell transplantation depend on safe hematopoietic stem cell (HSC) cryopreservation and storage. Several successful methods for cryopreservation and storage have been established and are commonly used all over the world. However, little is known about the effects of long-term cryopreservation on the capacity to sustain a complete immunohematopoietic engraftment. Several authors have investigated stem cell viability after cryopreservation and storage for more than 5 years and reported preclinical good viabilities in terms of dye-exclusion or colony-forming capability in vitro. Only two studies using BM cryopreserved for more than 5 years for transplantation are reported, but they did not provide proof of trilineage engraftment. In February 1997 at our institution, a patient with relapsed non-Hodgkin's lymphoma underwent ABMT with BM harvested in February 1990. He achieved a granulocyte count > 500 x 10(6)/L on day 21 and a self-supporting platelet count > 20 x 10(9)/L on day 30. After day 29, his hemoglobin level was satisfactory without need of transfusion support. This successful trilineage engraftment with cryopreserved BM that had been stored for 7 years suggests that HSC are able to maintain their capability to reconstitute hematopoiesis for a long time.