Evaluation of Circulating Endothelial Cells as Direct Marker of Endothelial Damage in Allo-Transplant Recipients at High Risk of Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome.

Sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease (VOD), is a rare but potentially fatal complication following allogenic hematopoietic cell transplantation (allo-HCT). Timely identification of SOS/VOD to allow for prompt treatment is critical, but identifying a VOD-predictive biomarker remains challenging. Given the pivotal role of endothelial dysfunction in SOS/VOD pathophysiology, the CECinVOD study prospectively evaluated levels of circulating endothelial cells (CECs) in patients undergoing allo-HCT with a myeloablative conditioning (MAC) regimen to investigate the potential of CEC level in predicting and diagnosing SOS/VOD. A total of 150 patients from 11 Italian bone marrow transplantation units were enrolled. All participants were age >18 years and received a MAC regimen, putting them at elevated risk of developing SOS/VOD. Overall, 6 cases of SOS/VOD (4%) were recorded. CECs were detected using the Food and Drug Administration-approved CellSearch system, an immunomagnetic selection-based platform incorporating ferrofluid nanoparticles and fluorescent-labeled antibodies, and were defined as CD146+, CD105+, DAPI+, or CD45-. Blood samples were collected at the following time points: before (T0) and at the end of conditioning treatment (T1), at neutrophil engraftment (T2), and at 7 to 10 days postengraftment (T3). For patients who developed VOD, additional samples were collected at any suspected or proven VOD onset (T4) and weekly during defibrotide treatment (T5 to T8). A baseline CEC count >17/mL was associated with an elevated risk of SOS/VOD (P = .04), along with bilirubin level >1.5 mg/mL and a haploidentical donor hematopoietic stem cell source. Postconditioning regimen (T1) CEC levels were elevated (P = .02), and levels were further increased at engraftment (P < .0001). Additionally, patients developing SOS/VOD after engraftment, especially those with late-onset SOS/VOD, showed a markedly higher relative increase (>150%) in CEC count. Multivariate analysis supported these findings, along with a high Endothelial Activation and Stress Index (EASIX) score at engraftment (T2). Finally, CEC kinetics corresponded with defibrotide treatment. After the start of therapy (T4), CEC levels showed an initial increase in the first week (T5), followed by a progressive decrease during VOD treatment (T6 and T7) and a return to pre-SOS/VOD onset levels at resolution of the complication. This prospective multicenter study reveals a low incidence of SOS/VOD in high-risk patients compared to historical data, in line with recent reports. The results from the CECinVOD study collectively confirm the endothelial injury in allo-HCT and its role in in the development of SOS/VOD, suggesting that CEC level can be a valuable biomarker for diagnosing SOS/VOD and identifying patients at greater risk of this complication, especially late-onset SOS/VOD. Furthermore, CEC kinetics may support treatment strategies by providing insight into the optimal timing for discontinuing defibrotide treatment.

High risk-myelodysplastic syndrome following CAR T-cell therapy in a patient with relapsed diffuse large B cell lymphoma: A case report and literature review.

Background: Chimeric antigen receptor (CAR) T-cell therapy represents the most advanced immunotherapy against relapsed/refractory B cell malignancies. While cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome are distinctive, known CAR T-cell acute adverse events, hematological toxicity has been increasingly reported. Cytopenia following CAR T-cell treatment is attributed in most cases to lymphodepletion regimens, bridging chemotherapy, or radiotherapy. However, when cytopenia becomes prolonged, the development of myelodysplastic syndrome (MDS) should be considered. Case presentation: We report a case of high risk (HR)-MDS following CAR T-cell therapy in a patient with relapsed diffuse large B cell lymphoma. Eight months after CAR T-cell infusion, the blood count showed progressive, worsening cytopenia and the bone marrow biopsy revealed multilineage dysplasia without excess of blasts associated with chromosome 7 deletion and RUNX1 mutation. Next generation sequencing analysis, retrospectively performed on stored samples, showed a germ line CSF3R mutation, CEBPA clonal hematopoiesis, but no RUNX1 lesion. Conclusion: We describe a case of HR-MDS, with deletion of chromosome 7 and acquisition of RUNX1 mutation, developing after CAR T-cell therapy in a patient with clonal hematopoiesis (CH). Previous chemotherapy favored MDS onset; however, we could not exclude the fact that the impairment of immunosurveillance related to either lymphodepletion or CAR T-cell infusion may play a role in MDS development. Thus, we designed a multicenter prospective study (ClonHema-CAR-T-Study) to investigate if cytopenia after CAR T-cell treatment may be due to underling CH as well as the presence of secondary myeloid malignancies.

Targeting the immune microenvironment in Waldenström macroglobulinemia via halting the CD40/CD40-ligand axis.

Recent investigations have improved our understanding of the molecular aberrations supporting Waldenström macroglobulinemia (WM) biology; however, whether the immune microenvironment contributes to WM pathogenesis remains unanswered. First, we showed how a transgenic murine model of human-like lymphoplasmacytic lymphoma/WM exhibits an increased number of regulatory T cells (Tregs) relative to control mice. These findings were translated into the WM clinical setting, in which the transcriptomic profiling of Tregs derived from patients with WM unveiled a peculiar WM-devoted messenger RNA signature, with significant enrichment for genes related to nuclear factor κB-mediated tumor necrosis factor α signaling, MAPK, and PI3K/AKT, which was paralleled by a different Treg functional phenotype. We demonstrated significantly higher Treg induction, expansion, and proliferation triggered by WM cells, compared with their normal cellular counterpart; with a more profound effect within the context of CXCR4C1013G-mutated WM cells. By investigating the B-cell-to-T-cell cross talk at single-cell level, we identified the CD40/CD40-ligand as a potentially relevant axis that supports WM cell-Tregs interaction. Our findings demonstrate the existence of a Treg-mediated immunosuppressive phenotype in WM, which can be therapeutically reversed by blocking the CD40L/CD40 axis to inhibit WM cell growth.

Allogeneic Solid Platelet-Rich Plasma for Persistent Epithelial Neurotrophic Defects: A Protocol and Pilot Study.

PURPOSE: Here, we present the procedure to obtain allogeneic solid platelet-rich plasma (PRP) and its use in a pilot study of patients with persistent neurotrophic epithelial defects. METHODS: We included 4 eyes of 4 patients with persistent neurotrophic epithelial defects unresponsive to other therapies from a single institution. PRP and thrombin were produced by the Department of Transfusion Medicine from healthy blood donors. PRP was activated in its solid form in the operating room with addition of thrombin and calcium gluconate 10% and applied on the cornea with fibrin glue and soft contact lens. Corneal healing time, corneal esthesiometry, visual acuity, Oxford staining score, Ocular Surface Disease Index questionnaire, and Schirmer I test were recorded. Anterior segment optical coherence tomography and in vivo confocal microscopy were also evaluated over the 4-month follow-up period. RESULTS: The persistent epithelial defect healed in all patients in the first 10 days. During the follow-up, there was an absence of recurrences. For all patients, there was a reduction in Ocular Surface Disease Index questionnaire score (case 1: -55 points, -73.3%; case 2: -26.3 points, -58.4%; case 3: -56 points, -69.1%; case 4: -20 points, -26.6%; mean reduction: 39.3 points, 56.85%) and Oxford staining score (case 1, 2, and 3: 3 points decrease; case 4: 2 points decrease; mean reduction: -2.75 points). CONCLUSIONS: Allogeneic solid PRP in combination with fibrin glue may facilitate wound healing in neurotrophic persistent epithelial defects. Further prospective studies are needed to quantify its efficacy.

Timely Leukapheresis May Interfere with the "Fitness" of Lymphocytes Collected for CAR-T Treatment in High Risk DLBCL Patients.

The development of chimeric antigen receptor (CAR)-T cell therapy has revolutionized the treatment of hematological diseases. However, approximately 60% of patients relapse after CAR-T cell therapy, and no clear cause for this failure has been identified. The objective of the Bio-CAR-T BS study (ClinicalTrials.gov: NCT05366569) is to improve our understanding of the lymphocyte harvest to maximize the quality of the CAR-T cell product. Of the 14 patients enrolled, 11 were diagnosed with DLBCL, 2 with PMBCL, and 1 with ALL. Five of 11 DLBCL patients met the criteria for "pre-emptive" Lymphocytes-apheresis (being at high risk of second relapse), and 6 were included in the standard-of-care Lymphocytes-apheresis group. Previous autologous stem cell transplantation (ASCT) and age were significantly different between the two groups. At the time of Lymphocyte-apheresis, patients in the "pre-emptive" group had more "fit" lymphocytes (higher CD4+/CD8+ ratio; higher naïve T cells levels) compared with standard group, probably due to the impact of ASCT. At the same time, also being older than 60 years results in a more "exhausted" lymphocyte profile. Overall, "pre-emptive" Ly-apheresis in DLBCL patients at high risk of relapse appears to be feasible and may allow the timely collection of "fit" lymphocytes for CAR-T cell manufacturing.

The role of clonal hematopoiesis as driver of therapy-related myeloid neoplasms after autologous stem cell transplantation.

Therapy-related myeloid neoplasm (t-MN) is a threatening complication of autologous stem cell transplantation (ASCT). Detecting clonal hematopoiesis (CH) mutations in cryopreserved cells before ASCT has been associated with a higher risk of t-MN, but the evolution of molecular abnormalities from pre-ASCT to t-MN, within the same patient, remains to be elucidated. We evaluated the mutational profile of 19 lymphoma/myeloma patients, at both pre-ASCT and t-MN diagnosis, using a targeted NGS approach; 26 non-developing t-MN control patients were also studied pre-ASCT. At ASCT, we found a higher frequency of CH in patients developing t-MN (58%) than in those who did not (23%) (P = 0.029); mutations in epigenetic (DNMT3A, TET2, and ASXL1) and DNA repair genes (PPM1D, RAD21, TP53, and STAG2) were the most represented. At t-MN, CH increased to 82% of patients. Cumulative mutational burden and variant allele frequency (VAF) also increased at t-MN. CH clones detected at ASCT were found at t-MN in eight out of 16 patients, mainly with stable VAF. Among the new driver mutations appeared at t-MN, TP53 increased from one to 13 mutations, in nine patients; being associated with complex karyotype. Mutations in transcription factor (RUNX1, CEBPA) and intracellular signaling genes (FLT3, RAS genes) also increased from three to 17 mutations in eight patients, presenting with a normal karyotype. Overall, we found that preexisting CH at ASCT rarely causes t-MN directly, but may rather facilitate the appearance of new mutations, especially those involving TP53, RUNX1, and RAS, that can drive the evolution to t-MN of at least two distinct types.

Comparative Mutational Profiling of Hematopoietic Progenitor Cells and Circulating Endothelial Cells (CECs) in Patients with Primary Myelofibrosis.

A role of endothelial cells (ECs) in Primary Myelofibrosis (PMF) was supposed since JAK2 mutation was found in endothelial precursor cells (EPCs) and in ECs captured by laser microdissection. By Cell Search method, the circulating endothelial cells (CECs) from 14 PMF patients and 5 healthy controls have been isolated and compared by NGS with CD34+Hematopoietic stem and progenitors cells (HSPCs) for panel of 54 myeloid-associated mutations. PMF patients had higher levels of CECs. No mutation was found in HSPCs and CECs from controls, while CECs from PMF patients presented several somatic mutations. 72% of evaluable patients shared at least one mutation between HSPCs and CECs. 2 patients shared the JAK2 mutation, together with ABL1, IDH1, TET2 and ASXL1, KMT2A, respectively. 6 out of 8 shared only NON MPN-driver mutations: TET2 and NOTCH1 in one case; individual paired mutations in TP53, KIT, SRSF2, NOTCH1 and WT1, in the other cases. In conclusion, 70% of PMF patients shared at least one mutation between HSPCs and CECs. These latter harbored several myeloid-associated mutations, besides JAK2V617F mutation. Our results support a primary involvement of EC in PMF and provide a new methodological approach for further studies exploring the role of the "neoplastic" vascular niche.

Polysaccharides on gelatin-based hydrogels differently affect chondrogenic differentiation of human mesenchymal stromal cells.

Selection of feasible hybrid-hydrogels for best chondrogenic differentiation of human mesenchymal stromal cells (hMSCs) represents an important challenge in cartilage regeneration. In this study, three-dimensional hybrid hydrogels obtained by chemical crosslinking of poly (ethylene glycol) diglycidyl ether (PEGDGE), gelatin (G) without or with chitosan (Ch) or dextran (Dx) polysaccharides were developed. The hydrogels, namely G-PEG, G-PEG-Ch and G-PEG-Dx, were prepared with an innovative, versatile and cell-friendly technique that involves two preparation steps specifically chosen to increase the degree of crosslinking and the physical-mechanical stability of the product: a first homogeneous phase reaction followed by directional freezing, freeze-drying and post-curing. Chondrogenic differentiation of human bone marrow mesenchymal stromal cells (hBM-MSC) was tested on these hydrogels to ascertain whether the presence of different polysaccharides could favor the formation of the native cartilage structure. We demonstrated that the hydrogels exhibited an open pore porous morphology with high interconnectivity and the incorporation of Ch and Dx into the G-PEG common backbone determined a slightly reduced stiffness compared to that of G-PEG hydrogels. We demonstrated that G-PEG-Dx showed a significant increase of its anisotropic characteristic and G-PEG-Ch exhibited higher and faster stress relaxation behavior than the other hydrogels. These characteristics were associated to absence of chondrogenic differentiation on G-PEG-Dx scaffold and good chondrogenic differentiation on G-PEG and G-PEG-Ch. Furthermore, G-PEG-Ch induced the minor collagen proteins and the formation of collagen fibrils with a diameter like native cartilage. This study demonstrated that both anisotropic and stress relaxation characteristics of the hybrid hydrogels were important features directly influencing the chondrogenic differentiation potentiality of hBM-MSC.

Chitosan-based scaffold counteracts hypertrophic and fibrotic markers in chondrogenic differentiated mesenchymal stromal cells.

Cartilage tissue engineering remains problematic because no systems are able to induce signals that contribute to native cartilage structure formation. Therefore, we tested the potentiality of gelatin-polyethylene glycol scaffolds containing three different concentrations of chitosan (CH; 0%, 8%, and 16%) on chondrogenic differentiation of human platelet lysate-expanded human bone marrow mesenchymal stromal cells (hBM-MSCs). Typical chondrogenic (SOX9, collagen type 2, and aggrecan), hypertrophic (collagen type 10), and fibrotic (collagen type 1) markers were evaluated at gene and protein level at Days 1, 28, and 48. We demonstrated that 16% CH scaffold had the highest percentage of relaxation with the fastest relaxation rate. In particular, 16% CH scaffold, combined with chondrogenic factor TGFß3, was more efficient in inducing hBM-MSCs chondrogenic differentiation compared with 0% or 8% scaffolds. Collagen type 2, SOX9, and aggrecan showed the same expression in all scaffolds, whereas collagen types 10 and 1 markers were efficiently down-modulated only in 16% CH. We demonstrated that using human platelet lysate chronically during hBM-MSCs chondrogenic differentiation, the chondrogenic, hypertrophic, and fibrotic markers were significantly decreased. Our data demonstrate that only a high concentration of CH, combined with TGFß3, creates an environment capable of guiding in vitro hBM-MSCs towards a phenotypically stable chondrogenesis.

The clinical use of circulating tumor cells (CTCs) enumeration for staging of metastatic breast cancer (MBC): International expert consensus paper.

BACKGROUND: The heterogeneity of metastatic breast cancer (MBC) necessitates novel biomarkers allowing stratification of patients for treatment selection and drug development. We propose to use the prognostic utility of circulating tumor cells (CTCs) for stratification of patients with stage IV disease. METHODS: In a retrospective, pooled analysis of individual patient data from 18 cohorts, including 2436 MBC patients, a CTC threshold of 5 cells per 7.5 ml was used for stratification based on molecular subtypes, disease location, and prior treatments. Patients with ≥ 5 CTCs were classified as Stage IVaggressive, those with < 5 CTCs as Stage IVindolent. Survival was analyzed using Kaplan-Meier curves and the log rank test. RESULTS: For all patients, Stage IVindolent patients had longer median overall survival than those with Stage IVaggressive (36.3 months vs. 16.0 months, P < 0.0001) and similarly for de novo MBC patients (41.4 months Stage IVindolent vs. 18.7 months Stage IVaggressive, p < 0.0001). Moreover, patients with Stage IVindolent disease had significantly longer overall survival across all disease subtypes compared to the aggressive cohort: hormone receptor-positive (44 months vs. 17.3 months, P < 0.0001), HER2-positive (36.7 months vs. 20.4 months, P < 0.0001), and triple negative (23.8 months vs. 9.0 months, P < 0.0001). Similar results were obtained regardless of prior treatment or disease location. CONCLUSIONS: We confirm the identification of two subgroups of MBC, Stage IVindolent and Stage IVaggressive, independent of clinical and molecular variables. Thus, CTC count should be considered an important tool for staging of advanced disease and for disease stratification in prospective clinical trials.

Counting circulating endothelial cells in allo-HSCT: an ad hoc designed polychromatic flowcytometry-based panel versus the CellSearch System.

Physio-pathologic interrelationships between endothelial layer and graft-versus-host disease (GVHD) have been described leading to assess the entity "endothelial GVHD" as the early step for clinical manifestations of acute GVHD. The availability of the CellSearch system has allowed us to monitor Circulating Endothelial Cells (CEC) changes in allogeneic hematopoietic stem cell transplantation (allo-HSCT) as useful tool to help clinicians in GVHD diagnostic definition. We have compared CEC counts generated by an ad hoc designed polychromatic-flowcytometry (PFC) Lyotube with those of the CellSearch system. CEC were counted in parallel at 5 timepoints in 50 patients with malignant hematologic disorders undergoing allo-HSCT (ClinicalTrials.gov, NCT02064972). Spearman rank correlation showed significant association between CEC values at all time points (p = 0.0001). The limits of agreement was demonstrated by Bland Altman plot analysis, showing bias not significant at T1, T3, T4, while at T2 and T5 resulted not estimable. Moreover, Passing Bablok regression analysis showed not significant differences between BD Lyotube and CellSearch system. We show that CEC counts, generated with either the CellSearch system or the PFC-based panel, have a superimposable kinetic in allo-HSCT patients and that both counting procedures hold the potential to enter clinical routine as a suitable tool to assist clinicians in GVHD diagnosis.

Collapse of the Plasmacytoid Dendritic Cell Compartment in Advanced Cutaneous Melanomas by Components of the Tumor Cell Secretome.

Melanoma is an immunogenic neoplasm infiltrated by T cells, although these adaptive T cells usually fail to eradicate the tumor. Plasmacytoid dendritic cells (PDCs) are potent regulators of the adaptive immune response and can eliminate melanoma cells via TLR-mediated effector functions. The PDC compartment is maintained by progressively restricted bone marrow progenitors. Terminally differentiated PDCs exit the bone marrow into the circulation, then home to lymph nodes and inflamed peripheral tissues. Infiltration by PDCs is documented in various cancers. However, their role within the melanoma immune contexture is not completely known. We found that in locoregional primary cutaneous melanoma (PCM), PDC infiltration was heterogeneous, occurred early, and was recurrently localized at the invasive margin, the site where PDCs interact with CD8+ T cells. A reduced PDC density was coupled with an increased Breslow thickness and somatic mutations at the NRAS p.Q61 codon. Compared with what was seen in PCM, high numbers of PDCs were found in regional lymph nodes, as also identified by in silico analysis. In contrast, in metastatic melanoma patients, PDCs were mostly absent in the tumor tissues and were significantly reduced in the circulation, particularly in the advanced M1c group. Exposure of circulating PDCs to melanoma cell supernatant (SN-mel) depleted of extracellular vesicles resulted in significant PDC death. SN-mel exposure also resulted in a defect of PDC differentiation from CD34+ progenitors. These findings indicate that soluble components released by melanoma cells support the collapse of the PDC compartment, with clinical implications for refining TLR agonist-based trials.

Bacterial Blood Stream Infections Negatively Impact on Outcome of Patients Treated with Allogeneic Stem Cell Transplantation: 6 Years Single-Centre Experience.

BACKGROUND: Blood stream infections (BSIs) represent a major complication of allo-SCT and are a major cause of morbidity and mortality during and after bone marrow aplasia. OBJECTIVES: The objective of this study was to describe the incidence and outcome of BSIs in a cohort of patients submitted to allo-SCT, in order to track changes of the epidemiology and bacteria resistance. METHODS: We retrospectively analyzed the microbiological data of 162 patients allotransplanted in Brescia University Hospital, over a period of 6 years. RESULTS: Eighty patients experienced a BSIs for a total of 119 isolates. In 77 cases (65%) a Gram positive bacteria was isolated, being coagulase negative Staphilococci the most frequent species (77% of the cases). In 42 cases (35%) a Gram negative bacteria was isolated (E. coli 57% and P. aeruginosa 24%). Fluoroquinolones resistance was frequent (90% for S. epidermidis, 92% for E. coli, 90% for P. aeruginosa). Methycillin resistance of S. epidermidis was 100%, 76% of E. coli were ESBL positive and among P. aeruginosa resistance to carbapenems was 40%. The 2 years overall survival of patients with BSIs vs patients without BSIs was 46% vs 60% (HR1,48, p=0,07). P. aeruginosa and E. coli were the species with the highest mortality (50% and 33%, respectively). CONCLUSIONS: These data confirm that BSIs, mainly sustained by Gram positive bacteria, are frequent in allotransplanted patients (50% of the cases) and may influence the outcome of allotransplanted patients, being antibiotics resistance highly frequent among these bacteria.

Mesenchymal stromal cells (MSCs) induce ex vivo proliferation and erythroid commitment of cord blood haematopoietic stem cells (CB-CD34+ cells).

A human bone marrow-derived mesenchymal stromal cell (MSCs) and cord blood-derived CD34+ stem cell co-culture system was set up in order to evaluate the proliferative and differentiative effects induced by MSCs on CD34+ stem cells, and the reciprocal influences on gene expression profiles. After 10 days of co-culture, non-adherent (SN-fraction) and adherent (AD-fraction) CD34+ stem cells were collected and analysed separately. In the presence of MSCs, a significant increase in CD34+ cell number was observed (fold increase = 14.68), mostly in the SN-fraction (fold increase = 13.20). This was combined with a significant increase in CD34+ cell differentiation towards the BFU-E colonies and with a decrease in the CFU-GM. These observations were confirmed by microarray analysis. Through gene set enrichment analysis (GSEA), we noted a significant enrichment in genes involved in heme metabolism (e.g. LAMP2, CLCN3, BMP2K), mitotic spindle formation and proliferation (e.g. PALLD, SOS1, CCNA1) and TGF-beta signalling (e.g. ID1) and a down-modulation of genes participating in myeloid and lymphoid differentiation (e.g. PCGF2) in the co-cultured CD34+ stem cells. On the other hand, a significant enrichment in genes involved in oxygen-level response (e.g. TNFAIP3, SLC2A3, KLF6) and angiogenesis (e.g. VEGFA, IGF1, ID1) was found in the co-cultured MSCs. Taken together, our results suggest that MSCs can exert a priming effect on CD34+ stem cells, regulating their proliferation and erythroid differentiation. In turn, CD34+ stem cells seem to be able to polarise the BM-niche towards the vascular compartment by modulating molecular pathways related to hypoxia and angiogenesis.

Analysis of Circulating Tumor Cells in Prostate Cancer Patients at PSA Recurrence and Review of the Literature.

BACKGROUND: Circulating tumor cells have been described in prostate cancer patients at diagnosis and in the metastatic phase but little is known on their role at biochemical PSA recurrence. PATIENTS AND METHODS: Patients radically cured with either prostatectomy or radiotherapy were sequentially included at PSA recurrence. The presence of CTCs was evaluated by the CellSearch system. RESULTS: Twenty-nine patients were accrued at PSA recurrence. Median PSA at recurrence was 7.2 ng/ml (range=3.86-51.0 ng/ml). The median time to PSA progression was 4.66 years (range=0.1-16 years). CTCs were detected in one patient (3%) with low numbers (1 CTC/7.5 ml). CONCLUSION: In patients radically cured for prostate cancer at biochemical recurrence, CTCs are detected at very low levels in a minority of patients. Further studies are required to investigate alternative methods of CTC detection and the possible role of the bone marrow pre-metastatic niche at biochemical recurrence.

Endothelial progenitor cells, defined by the simultaneous surface expression of VEGFR2 and CD133, are not detectable in healthy peripheral and cord blood.

Circulating endothelial cells (CEC) and their progenitors (EPC) are restricted subpopulations of peripheral blood (PB), cord blood (CB), and bone marrow (BM) cells, involved in the endothelial homeostasis maintenance. Both CEC and EPC are thought to represent potential biomarkers in several clinical conditions involving endothelial turnover/remodeling. Although different flow cytometry methods for CEC and EPC characterization have been published so far, none of them have reached consistent conclusions, therefore consensus guidelines with respect to CEC and EPC identification and quantification need to be established. Here, we have carried out an in depth investigation of CEC and EPC phenotypes in healthy PB, CB and BM samples, by optimizing a reliable polychromatic flow cytometry (PFC) panel. Results showed that the brightness of CD34 expression on healthy PB and CB circulating cells represents a key benchmark for the identification of CEC (CD45neg/CD34bright/CD146pos) respect to the hematopoietic stem cell (HSC) compartment (CD45dim/CD34pos/CD146neg). This approach, combined with a dual-platform counting technique, allowed a sharp CEC enumeration in healthy PB (n = 38), and resulting in consistent CEC counts with previously reported data (median = 11.7 cells/ml). In parallel, by using rigorous PFC conditions, CD34pos/CD45dim/CD133pos/VEGFR2pos EPC were not found in any healthy PB or CB sample, since VEGFR2 expression was never detectable on the surface of CD34pos/CD45dim/CD133pos cells. Notably, the putative EPC phenotype was observed in all analyzed BM samples (n = 12), and the expression of CD146 and VEGFR2, on BM cells, was not restricted to the CD34bright compartment, but also appeared on the HSC surface. Altogether, our findings suggest that the previously reported EPC antigen profile, defined by the simultaneous expression of VEGFR2 and CD133 on the surface of CD45dim/CD34pos cells, should be carefully re-evaluated and further studies should be conducted to redefine EPC features in order to translate CEC and EPC characterization into clinical practice.

PBSC mobilization in lymphoma patients: analysis of risk factors for collection failure and development of a predictive score based on the kinetics of circulating CD34+ cells and WBC after chemotherapy and G-CSF mobilization.

Autologous stem cell transplantation (ASCT) is a potentially curative treatment of lymphoma, but peripheral blood stem cell (PBSC) mobilization fails in some patients. PBSC mobilizing agents have recently been proved to improve the PBSC yield after a prior mobilization failure. Predictive parameters of mobilization failure allowing for a preemptive, more cost-effective use of such agents during the first mobilization attempt are still poorly defined, particularly during mobilization with chemotherapy + granulocyte colony-stimulating factor (G-CSF). We performed a retrospective analysis of a series of lymphoma patients who were candidates for ASCT, to identify factors influencing PBSC mobilization outcome. Premobilization parameters-age, histology, disease status, mobilizing protocol, and previous treatments-as well as white blood cell (WBC) and PBSC kinetics, markers potentially able to predict failure during the ongoing mobilization attempt, were analyzed in 415 consecutive mobilization procedures in 388 patients. We used chemotherapy + G-CSF in 411 (99%) of mobilization attempts and PBSC collection failed (<2 × 10(6) CD34+ PBSC/kg) in 13%. Multivariable analysis showed that only a low CD34+ PBSC count and CD34+ PBSC/WBC ratio, together with the use of nonplatinum-containing chemotherapy, independently predicted mobilization failure. Using these three parameters, we established a scoring system to predict risk of failure during mobilization ranging from 2 to 90%, thus allowing a selective use of a preemptive mobilization policy.

Circulating tumor cells in patients with recurrent or metastatic head and neck carcinoma: prognostic and predictive significance.

INTRODUCTION: We investigated the frequency of detection and the prognostic and predictive significance of circulating tumor cells (CTCs) in patients with recurrent/metastatic (R/M) head and neck carcinoma (HNC) before starting systemic therapy. PATIENTS AND METHODS: Using the CellSearch technology, CTCs were assessed prospectively in peripheral blood of 53 R/M-HNC patients. We performed spiking experiments to test the diagnostic performance of the CellSearch platform in identifying squamous carcinoma cells. RESULTS: CTCs were identified in 14 (26%) and 22 (41%) patients at baseline and at any time point, respectively. In univariate analysis ≥2 CTCs had a poorer prognostic role than 0-1 CTC. In multivariate analysis, the presence of one CTC or more was associated with a poor prognosis both in terms of progression-free survival (PFS) [Hazard Ratio (HR): 3.068, 95% confidence interval (CI): 1.53-6.13, p 0.002] and overall survival (OS) [HR: 3.0, 95% CI: 1.48-6.0, p 0.002]. A disease control after systemic therapy was obtained in 8% of CTC-positive patients as opposed to 45% in CTC-negative ones (p 0.03). The epidermal growth factor receptor (EGFR) expression was identified in 45% of CTC-positive patients. DISCUSSION: In conclusion, CTCs are detected in one out of three patients with RM-HNC. CTC detection is a strong prognostic parameter and may be predictive of treatment efficacy. The frequency of EGFR expression in CTCs seems to be lower than that expected in the primary tumor.

Changes in circulating endothelial cells count could become a valuable tool in the diagnostic definition of acute graft-versus-host disease.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is burdened by life-threatening complications, with graft-versus-host disease (GvHD) being the major cause of morbility and mortality. Recently, clinical and physiopathologic evidences showed that vascular endothelium can be a target of GvHD in the early phase and circulating endothelial cells (CECs) represent surrogate markers of endothelial damage. METHODS: Using the CellSearch System (Veridex LLC, Raritan, NJ), CECs were counted before (T1), after conditioning regimen (T2), at engraftment (T3), at GvHD onset (T4), and after steroid treatment (T5) in 40 patients (7 Hodgkin's Disease, 13 Acute Myeloblastic Leukemia, 5 Acute Lymphoblastic Leukemia, 8 Multiple Myeloma, 3 Chronic Lymphocytic Leukemia, 1 Non-Hodgkin Lymphoma, 1 Chronic Myeloid Leukemia, 2 Severe Aplastic Anemia) undergoing allo-HSCT. RESULTS: The median CEC per milliliter at T1 was 20 (n=33, range 4-718), in comparison to a value of 2 (range, 1-14) in controls (P<0.001). At T3, CEC per milliliter were 47 (range, 16-148) in GvHD patients and 92 (range, 23-276) in patients without GvHD (P=0.006). This difference remained significant in multivariate analysis (odds ratio, 0.97; 95% confidence interval, 0.96-0.99; P=0.02). At GvHD onset, the relative increase of CEC counts from time of engraftment (T4 vs. T3) was 44% (range, -43% to 569%) in GvHD patients versus 0% (range, -49% to 2%) in patients without GvHD (P=0.003), being confirmed as significant in multivariate analysis (odds ratio, 1.04; 95% confidence interval, 1.0-1.08; P=0.04). CONCLUSION: Changes in CEC count can represent a promising marker to monitor endothelial damage in patients undergoing allo-HSCT and could become a valuable tool in the diagnostic definition of GvHD.

Clinical validity of circulating tumour cells in patients with metastatic breast cancer: a pooled analysis of individual patient data.

BACKGROUND: We aimed to assess the clinical validity of circulating tumour cell (CTC) quantification for prognostication of patients with metastatic breast cancer by undertaking a pooled analysis of individual patient data. METHODS: We contacted 51 European centres and asked them to provide reported and unreported anonymised data for individual patients with metastatic breast cancer who participated in studies between January, 2003, and July, 2012. Eligible studies had participants starting a new line of therapy, data for progression-free survival or overall survival, or both, and CTC quantification by the CellSearch method at baseline (before start of new treatment). We used Cox regression models, stratified by study, to establish the association between CTC count and progression-free survival and overall survival. We used the landmark method to assess the prognostic value of CTC and serum marker changes during treatment. We assessed the added value of CTCs or serum markers to prognostic clinicopathological models in a resampling procedure using likelihood ratio (LR) χ(2) statistics. FINDINGS: 17 centres provided data for 1944 eligible patients from 20 studies. 911 patients (46·9%) had a CTC count of 5 per 7·5 mL or higher at baseline, which was associated with decreased progression-free survival (hazard ratio [HR] 1·92, 95% CI 1·73-2·14, p<0·0001) and overall survival (HR 2·78, 95% CI 2·42-3·19, p<0·0001) compared with patients with a CTC count of less than 5 per 7·5 mL at baseline. Increased CTC counts 3-5 weeks after start of treatment, adjusted for CTC count at baseline, were associated with shortened progression-free survival (HR 1·85, 95% CI 1·48-2·32, p<0·0001) and overall survival (HR 2·26, 95% CI 1·68-3·03) as were increased CTC counts after 6-8 weeks (progression-free survival HR 2·20, 95% CI 1·66-2·90, p<0·0001; overall survival HR 2·91, 95% CI 2·01-4·23, p<0·0001). Survival prediction was significantly improved by addition of baseline CTC count to the clinicopathological models (progression-free survival LR 38·4, 95% CI 21·9-60·3, p<0·0001; overall survival LR 64·9, 95% CI 41·3-93·4, p<0·0001). This model was further improved by addition of CTC change at 3-5 weeks (progression-free survival LR 8·2, 95% CI 0·78-20·4, p=0·004; overall survival LR 11·5, 95% CI 2·6-25·1, p=0·0007) and at 6-8 weeks (progression-free survival LR 15·3, 95% CI 5·2-28·3; overall survival LR 14·6, 95% CI 4·0-30·6; both p<0·0001). Carcinoembryonic antigen and cancer antigen 15-3 concentrations at baseline and during therapy did not add significant information to the best baseline model. INTERPRETATION: These data confirm the independent prognostic effect of CTC count on progression-free survival and overall survival. CTC count also improves the prognostication of metastatic breast cancer when added to full clinicopathological predictive models, whereas serum tumour markers do not. FUNDING: Janssen Diagnostics, the Nuovo-Soldati foundation for cancer research.