Bortezomib washout duration prior to stem cell mobilization in patients with newly diagnosed multiple myeloma.

OBJECTIVES: We aimed to determine the impact of washout period in patients with multiple myeloma between bortezomib-based induction regimens and the collection of stem cells. METHODS: This was a single-center historical prospective study, including all sequential newly diagnosed patients with myeloma between 2012 and 2017 that were given a first-line bortezomib-based induction therapy (≤6 cycles) followed by stem cell collection (n = 75). RESULTS: We found a statistically significant correlation between the days from last dose of bortezomib and both CD34+ cells/kg yield on the first collection day and the overall collected CD34+ cells/kg (r = .466, P < .001, and r = .341, P = .03, respectively). The optimal receiver operating curve's cutoff point was 8.5 days (79% sensitivity and 71% specificity, P = .001). On multivariate analysis, timing of last dose of bortezomib remained statistically significant (P = .01). Based on this, we developed a model to predict the total collected CD34+ cells/kg = 11.76 + 0.13 (timing in days of last dose of bortezomib) -0.1 (age) -1.39 (if female) -0.01 (≥PR) -1.35 (if prior radiation). CONCLUSIONS: Timing of last dose of bortezomib may predict a successful collection. A washout period of 9 days is associated with a better collection yield. A prospective validation of this novel finding is required.

Toxicity and efficacy of autologous hematopoietic cell transplantation in elderly patients with aggressive lymphoma: a historical prospective study.

High-dose therapy followed by autologous hematopoietic cell transplantation (HCT) prolongs overall survival in patients under 65 years old with relapsed aggressive lymphoma. We aimed to explore the toxicity and efficacy of HCT in patients over 65 years with aggressive lymphoma compared with younger patients. We compared the transplantation outcomes between patients ≥ 65 years (n = 58) and 55-64 years (n = 44) with chemosensitive aggressive lymphoma (DLBCL, MCL and TCL) that underwent HCT between 1999 and 2016 in the Tel-Aviv Medical Center. The median age was 68 (range, 65-74) and 61 (range, 55-64) years, respectively. There were no differences in the incidences of grade 3-4 mucositis, documented infections and pulmonary complications between the two groups. There was no difference in the incidences of secondary malignancies, relapse (p = .26), non-relapse mortality, (p = .77) and overall survival (p = .53). Multivariate analysis revealed that smoking was a risk factor for non-relapse mortality, while partial remission and > 2 lines of treatment prior HCT were associated with higher risk for relapse. Psycho-socioeconomic score was associated with prolonged hospitalization after HCT and recurrent hospitalizations. We conclude that patients ≥ 65 years old with aggressive lymphoma, compared to younger counterparts, have similar transplantation outcome. Improving habits and psychosocial factors may further improve outcomes in these patients.

Significant correlation between peripheral blood CD34+ cell count in children prior to aphaeresis and CD34+ cell yield following aphaeresis: A single-center experience.

Numerous adults' studies demonstrated that preaphaeresis CD34+ cells significantly correlate with the number of CD34+ cells collected by the aphaeresis procedure. Equivalent studies in children are scarce. We studied retrospectively 92 aphaeresis procedures performed following chemotherapy (44) or in steady state (48) in 60 pediatric patients (40 males, 20 females), median age of 7.5 years. Aphaeresis procedures were performed using a SPECTRA Optica (TERUMOBCT) continuous flow cell separator. CD34+ cell concentrations were assessed using flow cytometry. A highly significant correlation between peripheral CD34 cell count on the day of aphaeresis and CD34 cell yield per kg (R2  = .824, P < .0001) was demonstrated. A higher preaphaeresis CD34 cell count was demonstrated in patients with higher preaphaeresis white blood cell count, in patients with brain tumors, and in patients who received chemotherapy as part of their mobilization protocol. A threshold number of 20 peripheral CD34+ cell/µL was found to predict harvesting of 3 × 106 stem cells/kg, and 30 peripheral CD34+ cell/µL for harvesting of 5 × 106 stem cells/kg. This significant correlation between peripheral CD34 cell count and CD34 cell yield, and the threshold number of peripheral CD34 found to predict adequate harvesting can be useful in planning the optimal time for aphaeresis in children.

Combined plerixafor and granulocyte colony-stimulating factor for harvesting high-dose hematopoietic stem cells: Possible niche for plerixafor use in pediatric patients.

PB is a source of HSC, especially for autologous HCT in solid tumors. However, there is a risk of failing to achieve the target number of SC after mobilization with growth factors alone in patients who were heavily pretreated with chemotherapy or those in need for tandem transplants. SC were harvested from seven pediatric patients with solid tumors who were in need of autologous HCT following combination GCSF and plerixafor. Six of them received plerixafor after failing to achieve enough SC with GCSF only, while the seventh patient received the combined protocol upfront. All seven patients achieved the target number of SC according to their treatment protocol. There were no adverse events. All patients underwent autologous HCT using the harvested HSC and achieved full engraftment. A protocol for harvesting autologous HCT using GCSF and plerixafor is feasible and safe in children with solid tumors who had been heavily pretreated with chemotherapy or needed tandem transplants.

JAK2 mutation: an aid in the diagnosis of occult myeloproliferative neoplasms in patients with major intraabdominal vein thrombosis and normal blood counts.

BACKGROUND: Janus kinase-2 (JAK2) is mutated in a high proportion of patients with polycythemia vera and in a smaller number with essential thrombocythemia and primary myelofibrosis. Mutated JAK2 is an important diagnostic marker for myeloproliferative neoplasm (MPN) and may also play a major role in the pathogenesis of MPN. OBJECTIVES: To evaluate the prevalence of mutated JAK2 (JAK2-V617F) among patients with major intraabdominal vein thrombosis who had normal blood counts at diagnosis of the initial event. METHODS: The medical records of patients who presented with a major intraabdominal venous thrombosis and normal peripheral blood counts were obtained. JAK2-V617F mutation status was determined by real-time polymerase chain reaction. RESULTS: Twenty-two patients were available for this analysis and 9 (41%) were found to have JAK2-V617F. Patients with positive JAK2-V617F were younger and had more frequent clinical splenomegaly than those with wild-type JAK2. CONCLUSIONS: A high proportion of patients presenting with "idiopathic" major intraabdominal vein thrombosis and normal blood counts carry JAK2-V617F. We recommend searching for the mutation in this clinical setting to detect patients with occult MPN.

Anti-CD19 CAR-T therapy for EBV-negative posttransplantation lymphoproliferative disease-a single center case series.

Posttransplantation lymphoproliferative disease (PTLD) is a potentially fatal disorder arising after solid organ or hematopoietic cell transplantation. Survival rates of PTLD with diffuse large B-cell lymphoma (DLBCL) phenotype have improved due to the introduction of rituximab, however, reports on curative management of refractory PTLD are scarce. Here, we describe successful management of three patients with refractory EBV-negative PTLD with chimeric antigen receptor T-cell (CAR-T) therapy. All patients continued calcineurin inhibitors throughout the whole course of treatment. T-cell immunophenotyping was performed on both the apheresed cells and CAR-T product to investigate the T-cell compartment subpopulations. All three patients responded to a single infusion of tisagenlecleucel and two of them achieved CR. Toxicity profile was similar to other patients with non-PTLD DLBCL treated with CAR-T. No transplanted graft dysfunction was observed during the course of therapy. To our knowledge, this is the first report demonstrating that patients with EBV-negative refractory PTLD may benefit from CAR-T therapy, similarly to other patients with relapse/refractory DLBCL. A larger cohort of patients is needed to further establish proof-of-concept.

Safety and Immunogenicity of the BNT162b2 mRNA COVID-19 Vaccine in Patients after Allogeneic HCT or CD19-based CART therapy-A Single-Center Prospective Cohort Study.

Data are scarce regarding both the safety and immunogenicity of the BNT162b2 mRNA COVID-19 vaccine in patients undergoing immune cell therapy; thus, we prospectively evaluated these two domains in patients receiving this vaccine after allogeneic hematopoietic cell transplantation (HCT; n = 66) or after CD19-based chimeric antigen receptor T cell (CART) therapy (n = 14). Overall, the vaccine was well tolerated, with mild non-hematologic vaccine-reported adverse events in a minority of the patients. Twelve percent of the patients after the first dose and 10% of the patients after the second dose developed cytopenia, and there were three cases of graft-versus-host disease exacerbation after each dose. A single case of impending graft rejection was summarized as possibly related. Evaluation of immunogenicity showed that 57% of patients after CART infusion and 75% patients after allogeneic HCT had evidence of humoral and/or cellular response to the vaccine. The Cox regression model indicated that longer time from infusion of cells, female sex, and higher CD19+ cells were associated with a positive humoral response, whereas a higher CD4+/CD8+ ratio was correlated with a positive cellular response, as confirmed by the ELISpot test. We conclude that the BNT162b2 mRNA COVID-19 vaccine has impressive immunogenicity in patients after allogeneic HCT or CART. Adverse events were mostly mild and transient, but some significant hematologic events were observed; hence, patients should be closely monitored.

Highly sensitive patient-specific real-time PCR SNP assay for chimerism monitoring after allogeneic stem cell transplantation.

Chimerism analysis after allogeneic stem cell transplantation (allo-SCT) is an important diagnostic tool for the documentation of engraftment, early detection of graft failure, and recurrence of the disease. Current assays rely on the genetic polymorphism between the donor and the recipient, and allow semiquantitative or quantitative analysis of chimerism. The most common method in use is based on the amplification of the short tandem repeats (STR). This method, with 1% to 5 sensitivity, is useful for the documentation of engraftment, but is insufficient for the detection of minimal residual disease or early relapse, when medical intervention is urgently needed. Recently, single-nucleotide polymorphism (SNP) has been suggested as an alternative, more accurate system to monitor chimerism. The purpose of our study was to develop an easy, economical, and sensitive method for the detection of chimerism following allo-SCT using the SNP technology. Our approach is based on SNP patient-specific quantitative real-time polymerase chain reaction (PCR) using nonlabeled primers. Our results show that this allele-specific SNP real-time PCR approach is sensitive, relatively cheap, and offers a fast and reliable assay for the monitoring of hematopoietic engraftment and for the detection of minimal residual disease in patients after allo-SCT.

Leukomogenic factors downregulate heparanase expression in acute myeloid leukemia cells.

Heparanase is a heparan sulfate-degrading endoglycosidase expressed by mature monocytes and myeloid cells, but not by immature hematopoietic progenitors. Heparanase gene expression is upregulated during differentiation of immature myeloid cells. PML-RARalpha and PLZF-RARalpha fusion gene products associated with acute promyelocytic leukemia abrogate myeloid differentiation and heparanase expression. AML-Eto, a translocation product associated with AML FAB M2, also downregulates heparanase gene expression. The common mechanism that underlines the activity of these three fusion gene products involves the recruitment of histone deacetylase complexes to specific locations within the DNA. We found that retinoic acid that dissociates PML-RARalpha from the DNA, and which is used to treat acute promyelocytic leukemia patients, restores heparanase expression to normal levels in an acute promyelocytic leukemia cell line. The retinoic acid effects were also observed in primary acute promyelocytic leukemia cells and in a retinoic acid-treated acute promyelocytic leukemia patient. Histone deacetylase inhibitor reverses the downregulation of heparanase expression induced by the AML-Eto fusion gene product in M2 type AML. In summary, we have characterized a link between leukomogenic factors and the downregulation of heparanase in myeloid leukemic cells.

Receptors involved in microenvironment-driven molecular evolution of cancer cells.

Cells, including cancer cells, communicate with their microenvironment via various types of membrane receptors. An important down-stream effect of such interactions is a change in the molecular phenotype of the cells. The microenvironment-driven molecular evolution of cancer cells may induce either growth arrest or death of the cells or alternatively, boost their malignancy phenotype. In this paper we summarize studies from our own laboratory on interactions of cancer cells with microenvironmental ligands via two types of receptors that are not commonly associated with tumour progression i.e. the receptor for the Fc portion of IgG, and Ly-6 proteins of mouse and human origin. We also review information on interactions of tumour-associated chemokines and chemokine receptors with the corresponding microenvironmental factors. We demonstrate how these interactions may drive the molecular evolution of tumour cells and discuss the possible impact of this evolution on tumour progression.

Human Ly-6 antigen E48 (Ly-6D) regulates important interaction parameters between endothelial cells and head-and-neck squamous carcinoma cells.

Selectin ligands are crucial components in the interaction between endothelial cells and extravasating cancer cells and, thus, play an important role in metastasis formation. Head-and-neck squamous cell carcinoma (HNSCC) variants expressing high levels of E48, a human Ly-6 protein (E48(hi)), expressed higher levels of the fucose-generating FX enzyme and of the fucosylated E-selectin ligand sLe(a) than cells expressing low levels of E48 (E48(lo)). Signaling through E48 upregulated expression levels of these molecules in HNSCC. In this work, we provide further evidence supporting the E48-FX-sLe(a) link by showing that FX antisense oligonucleotides reduced sLe(a) expression levels in HNSCC. We also show that E48 may be causally involved in regulating expression levels in HNSCC of 2 additional enzymes involved in the biosynthesis of sLe(a), namely, ST-30 and FucTIII. Also, selectin-mediated adhesion of E48(hi) variants to activated HUVECs was significantly higher than that of E48(lo) variants. Transfection experiments utilizing sense or antisense E48 cDNA indicated that E48 may be causally involved in this adhesion. Chemokines are involved in the extravasation process of tumor cells. The release of chemoattractants from HNSCC variants differing in E48 expression was therefore analyzed. HNSCC did not release any chemoattractants but induced the release of such factors from HUVECs. Supernatants from E48(hi) variants were significantly more efficient than E48(lo) cells at inducing the release of chemoattractants from HUVECs. Transfection experiments indicated that E48 may be causally involved in the induction of chemoattractant release from HUVECs. Angiogenesis is an important manifestation of cancer-endothelium interactions. We therefore assayed for the presence of angiogenic factors in culture supernatants of HNSCC. Supernatants from E48(lo) variants contained significantly higher amounts of PDGF than E48(hi) cells. Transfection experiments indicated that E48 may be causally involved. Taken together, our results suggest that E48 controls important interaction parameters between HNSCC and endothelial cells.