Hematopoietic stem cell transplantation: bone marrow vs. mobilized peripheral blood

Validation of long-term handling and storage conditions for hematopoietic stem cell products for autologous transplants

Hematopoietic stem cells (HPSCs) are multipotent stem cells that can differentiate into lymphoid and myeloid progenitors, giving rise to white blood cells (WBCs), red blood cells (RBCs), and platelets. HPSCs are a widely used treatment for many hematological non-malignant and malignant disorders. HPSCs can be used in the fresh or cryopreserved state for future use. Fresh HPSCs are typically stored at 2-6°C for up to 72 hours and are primarily used for allogeneic transplants or autologous transplants in myeloma and lymphoma patients. However, in some cases of autologous donations, HPSC transplantation is delayed more than three days after collection. In such situations, the cells are thawed after short-term preservation, resulting in a 35% cell viability loss. This study aimed to investigate the quality of HPSCs products after long-term storage exceeding 72 hours. The quality of HPSCs products was assessed by measuring viable CD34+ cell count, the total number of nucleated cells (TNC), and HPSCs recovery after different storage intervals of up to 120 hours in hypothermal storage. The mean total cell viability decreased by 2.18% within 72 hours and 7.4% within 120 hours, while mean CD34+ cell recovery was 92.61 % at 72 hours and 83.83 % at 120 hours in hypothermal storage. The mean TNC recovery was 89.93% at 72 hours and 76.18 % at 120 hours. All products were free from bacterial contamination for up to 120 hours under hypothermal storage conditions.

An alternative test for determining autologous stem cell transplantation cell harvesting outcome: Comparison between predictive values of two tests

Daily CD34+ cells enumeration as a success indicator of stem cell pheresis procedure using flow cytometry is costly, lengthy, and labor-intensive. Thus, finding a simpler method to achieve the optimum time for harvesting the minimum required stem cells for transplantation could be helpful. The aim of this study was to evaluate the predictive value of reticulocytes fractions and their sensesivity and specificity in guiding CD34+ cell harvesting by G-CSF mobilization strategy. In this study, 49 candidates for autologous peripheral blood stem cell transplantation were enrolled. Before leukapheresis, the immature reticulocytes fraction (IRF) and CD34+ cell count were measured. Moreover, patients were evaluated for leukapheresis outcomes in two MNC and cMNC groups. Here we demonstrated that IRF, LFR, and MFR with the associated criterion of >17.3, ≤82.5, and >15.9, respectively, earned 100 % specificity and 47.2 %, 47.22 %, and 41.46 % sensitivity to predict the minimum required CD34+ cell count. Furthermore, IRF-V (Value) and MFR-V with the associated criterion of >0.77 and >0.55, respectively, earned 58.33 %, 66.67 % sensitivity and 84.62 %, 69.23 % of specificity, separately. As only MFR-V was able to predict the platelet engraftment (P-value = 0.014), none of the other above mentioned factors were not able to predict the neutrophil engraftment. Likewise, it was shown that patients who underwent MNC leukapheresis had a statistically significantly higher total WBC, harvested CD34⁺ cells, MNCs/ kg, and lower apheresis durations (P-values<0.05). Taken together, using IRF and its maturity stages seems to be a compelling predictor of minimal required CD34+ cells in autologous peripheral blood stem cell transplantation.

G-CSF-induced myeloid cells stimulated by TLR2 enhance engraftment after allogeneic hematopoietic stem cell transplantation

A high frequency of G-CSF-mobilized myeloid cells (gMCs) in a donor graft accelerates hematopoietic recovery after peripheral blood stem cell transplantation (PBSCT). However, because of the limited functional efficacy of gMCs, repeated transfusions of gMCs are frequently required. In this study, we investigated a strategy to improve the functional capacity of gMCs during hematopoietic engraftment after allogeneic transplantation. We found that toll-like receptor 2 (TLR2) is constitutively expressed on gMCs. Treating gMCs with the synthetic TLR2 ligand Pam(3)CSK(4) (PAM) dramatically enhanced IL-10 and TNF-α production. However, PAM treatment does not induce substantial cellular maturation. Moreover, PAM treatment significantly improved gMC survival. PAM treated gMCs significantly promoted myeloid differentiation of donor hematopoietic stem cells (HSCs), resulting in accelerated engraftment after allogeneic transplantation. Our data suggest that TLR2-stimulated gMCs may be a novel cellular therapeutic for increasing the efficiency of allogeneic hematopoietic stem cell transplantation (HSCT) by reducing infectious complications associated with delayed engraftment.

Ocular graft-versus-host disease after allogeneic stem cell transplantation

PURPOSE

To determine the prevalence and manifestations of ocular graft-versus-host disease (GvHD) after allogeneic stem cell transplantation (allo-SCT).

METHODS

Prospective study of 101 consecutive patients who received allo-SCT from 2004 to 2007. All patients received ophthalmologic examination for 3 months after allo-SCT, and those with ocular complaints were evaluated at 12 and 24 months thereafter. We registered ophthalmologic and hematological data, including the indication for allo-SCT, occurrence of systemic and ocular GvHDs, ocular manifestations, and various ocular treatments.

RESULTS

Over time, ocular GvHD developed in 54% of patients and consisted mainly of dry eyes and conjunctivitis, which increased in severity during follow-up; blepharitis and uveitis were less often encountered. Acute systemic GvHD, especially the involvement of mouth and skin, was strongly associated with ocular GvHD at 3 months (P = 0.000). Chronic GvHD was associated with the occurrence of ocular GvHD (P = 0.000), especially with the development of the dry eye. Although eye symptoms affecting activities of daily living were reported in 24 of 54 patients (44%) and 16 of 54 patients (30%) experienced temporary loss of visual acuity of more than 2 Snellen lines, only 1 developed permanent unilateral loss (counting fingers) because of ischemic vasculopathy. Cataract development was not encountered, and only 1 eye developed intraocular infection.

CONCLUSION

Ocular GvHD develops in a substantial part of patients after allo-SCT and decreases the activities of daily living.

Impact of GvHD on quality of life in long-term survivors of haematopoietic transplantation

Allogenic haematopoietic stem cell transplantation (HCT) has become an effective therapy in patients with various haematological malignancies. GvHD is known to be a major complication in this patient group and is assumed to have a major impact on patients' quality of life (QOL). Patients after BMT or transplantation of mobilized PBSCs were considered for enrolment in the study 6 months after transplantation. QOL and symptom burden were assessed using the EORTC QLQ-C30 and the QLQ-HDC29. Data from age- and sex-matched healthy controls were collected for comparison. In all, 100 patients (55.0% women; mean age 46.3 years) after allogeneic HCT were included in the study. In this patient group, we found a clinically relevant impact of GvHD on role functioning, global QOL, fatigue, dyspnoea, gastrointestinal side effects, worries/anxiety and skin problems. In comparison to healthy controls, various aspects of QOL were severely impaired. Our study revealed severe impairments of QOL in survivors of HCT, in particular in those suffering from GvHD. Taking into account, that the prevalence of GvHD might be higher in patients after PBSCT compared with patients after BMT, PBSCT is expected to lead to more severe impairments of QOL than BMT.

Factors influencing varicella zoster virus infection after allogeneic peripheral blood stem cell transplantation: low-dose acyclovir prophylaxis and pre-transplant diagnosis of lymphoproliferative disorders

Varicella zoster virus (VZV) infection is one of the frequent opportunistic infections after allogeneic bone marrow transplantation, with a high incidence of 30-50%. However, no data have been reported on VZV infection after allogeneic peripheral blood stem cell transplantation (PBSCT).

PATIENTS AND METHODS

We report a retrospective analysis of VZV infection in 192 allogeneic PBSCT recipients. Twenty-seven patients (14%) received long-term prophylaxis of low-dose acyclovir (200 mg twice daily orally > or =3 months) for recurrent oral (n=21) or genital herpes simplex virus infection (n=5) or for a previous history of recurrent VZV infection (n=1).

RESULTS

Forty-two patients (22%) developed VZV infections: localized (n=37) and disseminated infection (n=5). The incidence of VZV infection at 1 and 3 years was 19.3+/-3.3% and 36.8+/-5.2%, respectively. Complications included post-herpetic neuralgia (n=18, 43%), secondary bacterial infections (n=3), and intracranial hemorrhage (n=1) with 2 deaths. A higher risk factor for VZV infection was pre-transplant diagnosis of a lymphoproliferative disorder (LPD): chronic lymphocytic leukemia, Hodgkin's disease, or non-Hodgkin's lymphoma (P=0.021, 52.5% in LPD vs. 32.6% in non-LPD group). The use of low-dose acyclovir prophylaxis (P=0.043, 14.7% in acyclovir vs. 41.6% in nonacyclovir group) was found to be protective. Although no VZV infection episodes were noted during the period of acyclovir prophylaxis, 3 episodes of VZV infection were noted after acyclovir cessation.

CONCLUSION

The incidence of VZV infection after PBSCT was high at 36.8%, with patients transplanted for LPDs at higher risk. The long-term use of low-dose acyclovir may be protective for VZV infection, although it does not completely prevent rebound of late VZV infection.

The human-sheep chimeras as a model for human stem cell mobilization and evaluation of hematopoietic grafts' potential

OBJECTIVE

To investigate whether the sheep xenograft model of human hematopoiesis can be used to mimic mobilization of human hematopoietic stem cells in vivo.

MATERIAL AND METHODS

Sheep transplanted with 3.6 x 10(6) CD34+ from human adult bone marrow were mobilized 1.5 years posttransplantation with human granulocyte colony-stimulating factor for 5 days. At day 3 and 4 of mobilization, human cells were harvested from peripheral blood (PB) and bone marrow (BM) and were injected into secondary sheep recipients (n = 6) and these animals were analyzed for the presence of human cells in their BM and PB, starting at 3.5 months posttransplantation.

RESULTS

Maximum mobilization of human cells in PB occurred at day 3, with a 21-fold increase in total numbers of human cells, and a recovery of 5.5 x 10(4)/mL CD34+. In the BM, maximal numbers of human cells were achieved at day 4, with a 6.3-fold increase and a recovery of 1.5 x 10(4)/mL CD34+ cells. PB and BM mobilized human cells were then transplanted into new sheep recipients, and analysis at 3.5 months posttransplantation demonstrated that levels of human cell engraftment in BM of the group transplanted with mobilized PB were significantly lower than those transplanted with BM cells (0.6% +/- 0.1% vs 8.0% +/- 1.8%). Furthermore, in sheep transplanted with mobilized PB, the levels of human cells in circulation remained 2.5-fold higher than the levels of human cells found in their BM.

CONCLUSION

Mobilization of human cells in the sheep model parallels human PB and BM hematopoietic stem cells (HSC) mobilization in healthy human donors in their ability to engraft, differentiate, and repopulate secondary hosts. Thus, this model can become a useful tool to study mobilization regimens, mechanisms, and quality of products obtained.

Comparison of the Fenwal Amicus and Fresenius Com.Tec cell separators for autologous peripheral blood progenitor cell collection

Peripheral blood progenitor cells (PBPC) are commonly used as a stem cell source for autologous transplantation. This study was undertaken to evaluate blood cell separators with respect to separation results and content of the harvest. Forty autologous PBPC collections in patients with hematological malignancies were performed with either the Amicus or the COM.TEC cell separators. The median product volume was lower with the Amicus compared to the COM.TEC (125 mL vs. 300 mL; p < 0.001). There was no statistically significant difference in the median number of CD34+ cell/kg in product between the Amicus and the COM.TEC (3.0 x 10(6) vs. 4.1 x 10(6); p = 0.129). There was a statistically higher mean volume of ACD used in collections on the Amicus compared to the COM.TEC (1040 +/- 241 mL vs. 868 +/- 176 mL; p = 0.019). There was a statistical difference in platelet (PLT) contamination of the products between the Amicus and the COM.TEC (0.3 x 10(11) vs. 1.1 x 10(11); p < 0.001). The median % decrease in PB PLT count was statistically higher in the COM.TEC compared to the Amicus instruments (18.5% vs. 9.5%; p = 0.028). In conclusion, both instruments collected PBPCs efficiently. However, Amicus has the advantage of lower PLT contamination in the product, and less decrease in PB platelet count with lower product volume in autologous setting.

Novel strategies for steroid-refractory acute graft-versus-host disease

PURPOSE OF REVIEW

Graft-versus-host disease is one of the commonest complications of allogeneic bone marrow or peripheral blood stem cell transplantation. This review will cover advances in the pathophysiology of graft-versus-host disease and new agents under investigation for the treatment of this disorder. Patients developing graft-versus-host disease who fail to respond to steroids have a poor prognosis. In this group of people, morbidity and mortality are very high.

RECENT FINDINGS

Novel agents are currently under investigation for the treatment of such devastating disorders. Pentostatin, denileukin diftitox, mycophenolate mofetil, extracorporeal photopheresis, and several monoclonal antibodies have been used, some of them with encouraging results.

SUMMARY

As supportive care improves and new agents are added to the armamentarium against steroid-refractory acute graft-versus-host disease, the prognosis of this entity may start to change. Patients with this complication after transplantation should be enrolled, whenever possible, in clinical trials to find effective therapies.

Autologous Peripheral Blood Mononuclear Cell Implantation for Patients With Peripheral Arterial Disease Improves Limb Ischemia

BACKGROUND

Implantation of bone marrow mononuclear cells, including endothelial progenitor cells, into ischemic limbs has been shown to improve collateral vessel formation. In the present study the safety and feasibility of autologous peripheral blood mononuclear cells (PBMNCs) implantation after granulocyte-colony stimulating factor (G-CSF)-induced mobilization was investigated in patients with severe peripheral arterial disease.

METHODS AND RESULTS

Six cases were enrolled: 5 of thromboangitis obliterans and 1 of arteriosclerosis obliterans. Following administration of G-CSF (10 microg . kg(-1) . day(-1)), PBMNCs were harvested and injected intramuscularly (5 legs and 1 arm) for 2 days for the patients with ischemia of the legs. No serious adverse events related to G-CSF administration, harvest or implantation were observed during this study period. Improvement in the ankle - brachial pressure index (ABI: >0.1) was seen in 4 patients at 4 weeks and ischemic ulcers improved in 3 of 3 patients. The mean maximum walking distance significantly increased from 203 m to 559 m (p=0.031) at 4 weeks and was sustained for 24 weeks. Significant improvement was seen in physiological functioning subscale of Short Form-36.

CONCLUSION

Implantation of PBMNCs collected after G-CSF administration could be an alternative to therapeutic angioplasty in patients with severe peripheral arterial disease.

In Vitro Proliferation and Expansion of Hematopoietic Progenitors Present in Mobilized Peripheral Blood from Normal Subjects and Cancer Patients

In the present study, we have assessed, in a comparative manner, the in vitro proliferation and expansion potentials of hematopoietic progenitor cells (HPC) present in mobilized peripheral blood from normal subjects (MPB-n; n = 18) and cancer patients (MPB-c; n = 18). The latter included patients with breast cancer (BrCa; n = 8), Hodgkin disease (HD; n = 4), non-Hodgkin lymphoma (NHL; n = 3), and acute myeloid leukemia (AML; n = 3). Progenitor cells from normal bone marrow (BM) and umbilical cord blood (UCB) were included as controls. HPC, enriched by a negative selection procedure, were cultured for 25 days, in serum-free liquid media in the presence of a cytokine combination including early- and late-acting cytokines. Our results demonstrate that the in vitro biological properties of progenitor cells present in MPB differ, depending on whether they are derived from healthy individuals, from patients with solid tumors, or from patients with hematological neoplasias. Among all cell sources analyzed, UCB-derived progenitors showed the greatest proliferation and expansion potentials (1000-fold increase in total cell numbers on day 15, and a 22-fold increase in myeloid progenitor cell numbers, at day 10). Progenitor cells present in MPB from hematologically normal individuals showed proliferation and expansion potentials comparable to those of HPC from normal BM (500-fold increase in total cell numbers on day 15, and a 14-fold increase in myeloid progenitor cell numbers, at day 10). The proliferation/expansion potentials of MPB progenitors from BrCa patients were also within the normal range, although in the lower levels (327-fold increase in total cell numbers, on day 15, and 11.8-fold increase in myeloid progenitors, at day 10). In contrast, progenitors present in MPB from patients with HD, NHL, and especially AML, showed reduced in vitro capacities (119-, 102-, and 51-fold increase in total cell numbers, respectively; and 8-, 4-, and 2.6-fold increase in myeloid progenitor cells, respectively). To our knowledge, this is the first report in which the in vitro proliferation and expansion potentials of HPC from MPB from normal subjects and cancer patients are assessed simultaneously in a comparative manner.