Features of the engraftment of allogeneic hematopoietic stem cells using reduced-intensity conditioning regimens

Outpatient allogeneic hematopoietic stem-cell transplantation: a review

Hematopoietic stem-cell transplantation (HSCT) is usually performed in well-equipped units inside a hospital. The cost of this in-hospital transplant is usually very high; therefore, this procedure is more difficult to perform in low- and middle-income countries. Autologous outpatient HSCT is now a common procedure; however, outpatient allogeneic transplants are more complicated. Only a few centers in the world have incorporated outpatient HSCT. This transplant requires special adaptation, like a day hospital, careful selection of patients, oral medications, and the patient must live relatively close to the hospital. The results until now suggest that this outpatient transplant is factible and similar to inpatient HSCT. The objective was to review and describe the different methods and results following an outpatient allogeneic-HSCT strategy.

Self-reported changes in the expanded disability status scale score in patients with multiple sclerosis after autologous stem cell transplants: real-world data from a single center

In order to reset the immune system to baseline function, autologous hematopoietic stem cell transplantation (HSCT) has been performed in patients with multiple sclerosis (MS). After June 2015, 617 new consecutive patients with MS were autografted in our center with non-frozen peripheral blood stem cells. The autografts were performed on an out-patient basis, after conditioning with cyclophosphamide and rituximab. The aim of the study was the assessment of both safety and efficacy of the method. The study's primary co-end-points were recovery of granulocyte and platelet counts and transplant-related mortality. Secondary end-points were overall survival and clinical response (improvement or stabilization of the self-reported expanded disability status scale score). The protocol was registered in ClinicalTrials.gov identifier NCT02674217.0. We included 401 females and 216 males, with a median age of 46 years. A total of 259 patients had relapsing-remitting MS (RRMS), 228 had secondary progressive (SPMS) and 130 had primary progressive (PPMS) multiple sclerosis. All procedures were initially performed on an out-patient basis and only 32 individuals (5%) required hospitalization. One to three aphereses (median 1) were required to harvest at least 1 × 10⁶ /kg viable CD34⁺ cells. The total number of viable CD34⁺ infused cells ranged between 1 and 37·83 × 10⁶ /kg (median 5·68). Patients recovered more than 0·5 × 10⁹ /l absolute granulocytes by day 8 (median, range = 2-14), and platelet values were above 20 × 10⁹ /l by day 4 (median, range = 0-11). Eleven individuals required red blood cells and six needed platelet transfusions. To date, there have been no deaths attributable to the transplant, yielding a 30-month overall survival of 100%. Patients have been followed for 3-42 months (median = 12). The overall response rate (decrease or stabilization of the self-reported EDSS score) at 12 months was 78% for all patients (83% in RRMS, 78% in PPMS and 73% in SPMS), while the disability progression-free survival was 82% for all patients (86% in RRMS, 78·5% in SPMS and 78% in SPMS). Changes in the self-reported EDSS score in parallel with neurological improvement were observed in people with all types of MS after HSCT, employing the 'Mexican method'.

A Feasibility Study of the Full Outpatient Conduction of Hematopoietic Transplants in Persons with Multiple Sclerosis Employing Autologous Non-Cryopreserved Peripheral Blood Stem Cells

BACKGROUND

With the goal of achieving immune system reset, autologous hematopoietic stem cell transplantations have been performed in patients with multiple sclerosis (MS).

MATERIAL AND METHODS

Two hundred and eighty-six consecutive patients with MS were autografted in a single center using non-frozen peripheral blood stem cells (PBSCs), on an outpatient basis and conditioning with cyclophosphamide and rituximab. The protocol was registered in ClinicalTrials.gov identifier NCT02674217.

RESULTS

One hundred and ninety-four females and 92 males were included; the median age was 47. All procedures were started on an outpatient basis and only 8 persons needed to be admitted to the hospital during the procedure. In order to obtain at least 1 × 106/kg viable CD34 cells, 1-4 aphereses were performed (median 1). The total number of viable CD34+ cells infused ranged between 1 and 19.2 × 106/kg (median 4.6). Patients recovered above 0.5 × 109/L absolute granulocytes on median day 8 (range 0-12). Two individuals needed red blood cells but none needed platelet transfusions. There were no transplant-related deaths and the 128-month overall survival of the patients is 100%. In 82 persons followed up for 3 or more months, the Expanded Disability Status Scale diminished from a mean of 5.2-4.9, the best results being obtained in relapsing-remitting and primary progressive MS.

CONCLUSIONS

It is possible to conduct autotransplants for patients with MS employing non-frozen PBSCs and outpatient conduction. Additional information is needed to assess the efficacy of these procedures in the treatment of patients with MS.

Instrument- and protocol-dependent variation in the enumeration of CD34+ cells by flow cytometry

BACKGROUND

The information regarding the minimum number of CD34+ cells that are necessary to reconstitute hematopoiesis in patients undergoing peripheral blood progenitor cell transplantation is quite controversial. Some of the differences in these figures might be due to the selection of antibodies, staining protocols, and acquisition strategies for the flow cytometric enumeration of these cells.

STUDY DESIGN AND METHODS

Twenty-seven human umbilical cord blood samples and 33 leukapheresis products were consecutively collected for this study. Cells were stained following two different protocols, both using monoclonal antibodies to CD45 and CD34, and analyzed by the same operator in two different flow cytometers to enumerate the percentage of CD34+ mononuclear cells.

RESULTS

Relevant differences in the proportion of cells were encountered, and the correlation between the results yielded by both instruments and protocols, although statistically valid, was suboptimal.

CONCLUSIONS

Both interinstrument and interprotocol variation can provide additional explanation for the redundantly reported discrepancies concerning the numbers of CD34 cells that suffice to secure hemopoietic grafting. These results point to the need for new and different standardization approaches in this clinically relevant field.

Breaking dogmata to help patients: non-myeloablative haematopoietic stem cell transplantation

Various dogmata have been broken as a consequence of the evolution of knowledge in the area of allogeneic haematopoietic stem cell (HSC) transplantation. The following is now clear: for the successful engraftment of allogeneic HSC, bone marrow ablation of the recipient is not required; HSCs create their own space through graft-versus-host reactions; several malignancies can be eradicated by the graft-versus-tumour effect; HSC allografting can be conducted on an out-patient basis; HSC allografting can be done in aged or debilitated individuals; HSC allografting can be achieved without transfusion of blood products; and the costs of the allografting procedures can be substantially diminished. Despite the fact that HSC allografting with reduced intensity conditioning may be related to several disadvantages, such as mixed chimaerism and relapse of the malignancy, breaking these dogmata has resulted in availability of HSC allografting to a larger number of individuals worldwide, thus offering true curative therapeutic options to patients who otherwise would not qualify to be given these opportunities.

Decreased transfusion requirements in patients given stem cell allografts using a non-myeloablative conditioning regimen: a single institution experience

We report our experience of allogeneic peripheral blood stem cell transplantation using non-myeloablative conditioning regimens delivered and supported on an outpatient basis. A group of 44 patients underwent 47 allograft procedures using peripheral blood stem cells. Approximately one third of the individuals did not require red blood cells transfusions: the median of transfused red blood cells units was 1 (range 0-10). In addition one out of three did not require platelet transfusions either, the median of platelet transfusions being 1 (range 0-6). In fourteen allografts (30%) neither red blood cells nor platelet transfusions were used. An inverse correlation was found between the number of CD34 cells infused and the PRBC and PLT transfusion requirements, those patients receiving high numbers of CD34 cells needing fewer transfusions of both PRBC and platelets. The possibility of conducting allografts without transfusion of blood products in some patients may result in a decrease in both cost and the risks stemming from exposure to human blood derivatives.

Successful Allogeneic Stem Cell Transplantation with Nonmyeloablative Conditioning in Patients with Relapsed Hodgkin's Disease Following Autologous Stem Cell Transplantation

Use of myeloablative preparative therapy and allogeneic stem cell transplantation (alloSCT) as salvage therapy for adult patients with relapsed hematologic malignancies after autologous stem cell transplantation (autoSCT) is generally unsuccessful due to very high treatment-related mortality rates. We report here the outcome of HLA-matched related donor alloSCT following nonmyeloablative preparative therapy in two patients with Hodgkin's disease, relapsed after autologous stem cell graft. Times from autoSCT to alloSCT were 9 and 11 months, respectively. Preparative therapy consisted of the following: oral busulfan, 4 mg/kg on days -6 and -5; intravenous (i.v.) cyclophosphamide, 350 mg/m2 on days -4, -3 and, -2, and i.v. fludarabine, 30 mg/m2 on days -4, -3, and -2; oral cyclosporin A (CyA) 5 mg/kg was begun on day -1 and i.v. methotrexate 5 mg/m2 was delivered on days +1, +3, +5, and +11. Both patients achieved initial mixed chimerism as defined as > 1% donor peripheral white blood cells and did not receive prophylactic donor lymphocyte infusions; both showed conversion to final full-donor chimerism. Stage I acute graft-vs.-host disease occurred in one patient and both achieved sustained complete response. One patient died on day 233 as a consequence of drug-induced pulmonary toxicity, whereas the other patient remains in continued complete remission 513 days after allograft. This nonmyeloablative alloSCT strategy was well tolerated, was completed entirely on an out-patient basis, and can result in durable disease-free survival among patients with Hodgkin's disease after failed autoSCT. Further follow-up and evaluation of additional patients are required to conclusively establish the role of this strategy in treatment of hematologic malignancies after autologous transplantation.

Allogeneic stem cell transplantation using non-myeloablative conditioning regimens: results of the Mexican approach

We have used a novel method to conduct non-myeloablative stem cell transplantation (NST), making the following changes in previous methods: Use of the cheapest conditioning drugs, tailored number of apheresis sessions in the donors, elimination of ganciclovir and IgG, outpatient conduction when possible, diminished number of transfusions of blood products and diminished number of donor lymphocyte infusions. With this method, we have prospectively conducted 70 allografts in patients with different diseases: Chronic myelogenous leukemia, acute myelogenous leukemia, acute lymphoblastic leukemia, myelodysplasia, thalassemia major, relapsed Hodgkins disease, Blackfan-Diamond syndrome and aplastic anemia. In them, the median granulocyte recovery time to 0.5 x 10(9)/L was 11 d, whereas the median platelet recovery time to 20 x 10(9)/L was 12 d. Twenty patients did not need red blood cell transfusions and 17 did not need platelet transfusions. In 55 individuals (78%), the procedure could be completed fully on an outpatient basis. Follow-up times range between 30 and 800 d.: Four patients failed to engraft and recovered endogenous hemopoiesis; 16 patients (23%) developed acute graft versus-host disease (GVHD) whereas 28 (49%) developed chronic GVHD. Thirty two patients (47%) have died: 21 with a relapsing disease and seven as a result of GVHD; the median post-trasplant survival (SV) was 420 d., whereas the 12-mo. SV was 42%. The 100-day mortality was 3.8% and the transplant-related mortality was 14.2%. The median cost of the allografts was 18,000.00 US dollars. This method could be particularly adequate in developing countries, where very few individuals can afford the cost of a conventional bone marrow transplantation procedure.

Follow up of hemopoietic chimerism in individuals given allogeneic hemopoietic stem cell allografts using an immunosuppressive, non-myeloablative conditioning regimen: a prospective study in a single institution

Thirty consecutive patients were given non-myeloablative stem cell transplants (NST) and posttransplant chimerism was studied by several methods. In 16 individuals definitive proofs of chimerism have been shown: In 10 cases sex chimerism, in 7 cases chimerism shown by means of microsatellites, in 4 cases ABO chimerism, in two cases Rh chimerism and in one HLA-DR chimerism. In addition, in 9 individuals the disappearance of the molecular marker of the leukemia is an indirect evidence of the chimerism, as well as the presence of graft versus host disease (GVHD) in 17 allografted patients. Only in 6 patients no evidence of chimerism could be shown; all of them died as a result of either persistent or relapsing malignancy. Since the early patterns of chimerism may be predictive of either GVHD or graft loss in NST and, since therapeutic intervention (such as donor lymphocytes infusions) is based in the patterns of chimerism, it is possible that chimerism studies in these types of allografts should be ideally done more frequently than in conventional allotransplants.