Extracellular NK histones promote immune cell anti-tumor activity by inducing cell clusters through binding to CD138 receptor.

BACKGROUND: Natural killer (NK) cells are important anti-tumor cells of our innate immune system. Their anti-cancer activity is mediated through interaction of a wide array of activating and inhibitory receptors with their ligands on tumor cells. After activation, NK cells also secrete a variety of pro-inflammatory molecules that contribute to the final immune response by modulating other innate and adaptive immune cells. In this regard, external proteins from NK cell secretome and the mechanisms by which they mediate these responses are poorly defined. METHODS: TRANS-stable-isotope labeling of amino acids in cell culture (TRANS-SILAC) combined with proteomic was undertaken to identify early materials transferred between cord blood-derived NK cells (CB-NK) and multiple myeloma (MM) cells. Further in vitro and in vivo studies with knock-down of histones and CD138, overexpression of histones and addition of exogenous histones were undertaken to confirm TRANS-SILAC results and to determine functional roles of this material transferred. RESULTS: We describe a novel mechanism by which histones are actively released by NK cells early after contact with MM cells. We show that extracellular histones bind to the heparan sulfate proteoglycan CD138 on the surface of MM cells to promote the creation of immune-tumor cell clusters bringing immune and MM cells into close proximity, and thus facilitating not only NK but also T lymphocyte anti-MM activity. CONCLUSION: This study demonstrates a novel immunoregulatory role of NK cells against MM cells mediated by histones, and an additional role of NK cells modulating T lymphocytes activity that will open up new avenues to design future immunotherapy clinical strategies.

Development of adaptive immune effector therapies in solid tumors.

State-of-the-art treatment strategies have drastically ameliorated the outcome of patients affected by cancer. However, resistant and recurrent solid tumors are generally nonresponsive to conventional therapies. A central factor in the sequence of events that lead to cancer is an alteration in antitumor immune surveillance, which results in failure to recognize and eliminate the transformed tumor cell. A greater understanding of the dysregulation and evasion of the immune system in the evolution and progression of cancer provides the basis for improved therapies. Targeted strategies, such as T-cell therapy, not only generally spare normal tissues, but also use alternative antineoplastic mechanisms that synergize with other therapeutics. Despite encouraging success in hematologic malignancies, adaptive cellular therapies for solid tumors face unique challenges because of the immunosuppressive tumor microenvironment, and the hurdle of T-cell trafficking within scarcely accessible tumor sites. This review provides a brief overview of current cellular therapeutic strategies for solid tumors, research carried out to increase efficacy and safety, and results from ongoing clinical trials.

Long-term survival of patients with CLL after allogeneic transplantation: a report from the European Society for Blood and Marrow Transplantation.

Even with the availability of targeted drugs, allogeneic hematopoietic cell transplantation (allo-HCT) is the only therapy with curative potential for patients with CLL. Cure can be assessed by comparing long-term survival of patients to the matched general population. Using data from 2589 patients who received allo-HCT between 2000 and 2010, we used landmark analyses and methods from relative survival analysis to calculate excess mortality compared with an age-, sex- and calendar year-matched general population. Estimated event-free survival, overall survival and non-relapse mortality (NRM) 10 years after allo-HCT were 28% (95% confidence interval (CI), 25-31), 35% (95% CI, 32-38) and 40% (95% CI, 37-42), respectively. Patients who passed the 5-year landmark event-free survival (N=394) had a 79% probability (95% CI, 73-85) of surviving the subsequent 5 years without an event. Relapse and NRM contributed equally to treatment failure. Five-year mortality for 45- and 65-year-old reference patients who were event-free at the 5-year landmark was 8% and 47% compared with 3% and 14% in the matched general population, respectively. The prospect of long-term disease-free survival remains an argument to consider allo-HCT for young patients with high-risk CLL, and programs to understand and prevent late causes of failure for long-term survivors are warranted, especially for older patients.

GvHD after umbilical cord blood transplantation for acute leukemia: an analysis of risk factors and effect on outcomes.

Using the Center for International Blood and Marrow Transplant Research (CIBMTR) registry, we analyzed 1404 umbilical cord blood transplantation (UCBT) patients (single (<18 years)=810, double (⩾18 years)=594) with acute leukemia to define the incidence of acute GvHD (aGvHD) and chronic GvHD (cGvHD), analyze clinical risk factors and investigate outcomes. After single UCBT, 100-day incidence of grade II-IV aGvHD was 39% (95% confidence interval (CI), 36-43%), grade III-IV aGvHD was 18% (95% CI, 15-20%) and 1-year cGvHD was 27% (95% CI, 24-30%). After double UCBT, 100-day incidence of grade II-IV aGvHD was 45% (95% CI, 41-49%), grade III-IV aGvHD was 22% (95% CI, 19-26%) and 1-year cGvHD was 26% (95% CI, 22-29%). For single UCBT, multivariate analysis showed that absence of antithymocyte globulin (ATG) was associated with aGvHD, whereas prior aGvHD was associated with cGvHD. For double UCBT, absence of ATG and myeloablative conditioning were associated with aGvHD, whereas prior aGvHD predicted for cGvHD. Grade III-IV aGvHD led to worse survival, whereas cGvHD had no significant effect on disease-free or overall survival. GvHD is prevalent after UCBT with severe aGvHD leading to higher mortality. Future research in UCBT should prioritize prevention of GvHD.

Changing prognosis in paroxysmal nocturnal haemoglobinuria disease subcategories: an analysis of the International PNH Registry.

BACKGROUND: Paroxysmal nocturnal haemoglobinuria (PNH) is a rare disease. Although much progress has been made in the understanding of the pathophysiology of the disease, far less is known with respect to the clinical outcomes of patients with PNH. Few retrospective studies provide survival estimates, and even fewer have explored the clinical heterogeneity of the disease. Haemolytic and aplastic anaemia (AA) forms of the disease have been recognised as main disease categories, with the haemolytic form being associated with the worst prognosis by the largest studied cohort some years ago. AIMS: To describe mortality and causes of death in PNH overall and by PNH classification and to evaluate risk factors associated with mortality. METHODS: We analysed data of 2356 patients enrolled in the International PNH Registry with multivariate analyses, using time-dependent covariates. Patients were classified into haemolytic, AA/PNH syndrome or intermediate PNH. RESULTS: Overall, 122 (5.2%) patients died after enrolment, the incidence according to subcategories being 5.1, 11.7, 2.0 and 4.8% for patients with haemolytic PNH, AA-PNH, intermediate and insufficient data respectively. Older age and decreased performance status also affected survival in multivariate analysis. Improved outcome of patients with haemolytic PNH suggests that eculizumab treatment in PNH may be associated with improved survival. CONCLUSION: A detailed analysis of clinical presentations and causes of death in patients with PNH, overall and by disease subcategories, provide evidence that in the current era, patients with haemolytic PNH are no longer those who harbour the worst prognosis. This finding differs sharply from what has been previously reported.

Allogeneic hematopoietic SCT in multiple myeloma: long-term results from a single institution.

The role of allogeneic hematopoietic SCT (allo-HCT) in multiple myeloma (MM) remains controversial. A total of 58 patients received an allo-HCT (25 of them with myeloablative conditioning-allo-MAC-and 33 with reduced-intensity conditioning-allo-RIC) at our institution over a 28-year period. The CR rate for allo-MAC was 36%. The incidence of grade III-IV acute GVHD (aGVHD) and chronic GVHD (cGVHD) was 28% and 39%, respectively The TRM at any time was 60% and the main causes of death were aGVHD or infectious complications not directly related to GVHD. The estimated PFS and OS at 15 years were 8% and 15%, respectively. The CR rate with allo-RIC was 45%. The incidence of grade III-IV aGVHD and cGVHD were 24% and 41%, respectively. The TRM at any time was 33% and was mainly related to aGVHD. The estimated PFS and OS at 5 years were 22% and 38%, respectively. Despite its high TRM, a proportion of patients with high-risk myeloma (early relapse and newly diagnosed ultrahigh risk) may obtain long-term disease control with allo-HCT. New approaches aimed at decreasing the incidence of aGVHD, and consequently to decrease the TRM, are needed.

Transmissible cytotoxicity of multiple myeloma cells by cord blood-derived NK cells is mediated by vesicle trafficking.

Natural killer cells (NK) are important effectors of anti-tumor immunity, activated either by the downregulation of HLA-I molecules on tumor cells and/or the interaction of NK-activating receptors with ligands that are overexpressed on target cells upon tumor transformation (including NKG2D and NKP30). NK kill target cells by the vesicular delivery of cytolytic molecules such as Granzyme-B and Granulysin activating different cell death pathways, which can be Caspase-3 dependent or Caspase-3 independent. Multiple myeloma (MM) remains an incurable neoplastic plasma-cell disorder. However, we previously reported the encouraging observation that cord blood-derived NK (CB-NK), a new source of NK, showed anti-tumor activity in an in vivo murine model of MM and confirmed a correlation between high levels of NKG2D expression by MM cells and increased efficacy of CB-NK in reducing tumor burden. We aimed to characterize the mechanism of CB-NK-mediated cytotoxicity against MM cells. We show a Caspase-3- and Granzyme-B-independent cell death, and we reveal a mechanism of transmissible cell death between cells, which involves lipid-protein vesicle transfer from CB-NK to MM cells. These vesicles are secondarily transferred from recipient MM cells to neighboring MM cells amplifying the initial CB-NK cytotoxicity achieved. This indirect cytotoxicity involves the transfer of NKG2D and NKP30 and leads to lysosomal cell death and decreased levels of reactive oxygen species in MM cells. These findings suggest a novel and unique mechanism of CB-NK cytotoxicity against MM cells and highlight the importance of lipids and lipid transfer in this process. Further, these data provide a rationale for the development of CB-NK-based cellular therapies in the treatment of MM.

A variant in IRF3 impacts on the clinical outcome of AML patients submitted to Allo-SCT.

Allo-SCT has a strong curative potential for AML patients mainly due to a GVL effect. Unfortunately, GvL and GVHD are intimately linked. IFN regulatory factor-3 (IRF3), by modulating innate immune reactions, could impact on the incidence and intensity of GVL and GVHD. We analyzed two gene variants in IRF3 (rs7251 and rs2304205) on the clinical outcome of 249 AML patients submitted to HLA-identical sibling allo-SCT. Patients with a donor carrying the dominant GG gene variant in rs7251 had, as compared with GC and CC variants, a lower acute GVHD (aGVHD) III-IV incidence (4% vs 11% vs 27%; P=0.0078), a higher relapse incidence (49% vs 35% vs 26%; P=0.018), and lower TRM (7% vs 24% vs 18%; P=0.0065). In functional studies, the GG variant was associated with lower production of IFN-γ, decreased lymphocyte proliferation after antigen presentation by DCs, and lower cytotoxic response of mature natural killer cells. Patients carrying the AA dominant variant in rs2304205 had higher relapse incidence (50% vs 39% vs 18%, P=0.0068). The presence of both variants (GG in rs7251 and AA in rs2304205) in donors and patients resulted in a stronger clinical impact.

A constitutional variant in the transcription factor EP300 strongly influences the clinical outcome of patients submitted to allo-SCT.

An adequate response of the innate immune system after allo-SCT is crucial for the clinical outcome of patients submitted to this procedure. EP300 is one of the key genes of the innate immune system (IIS). We evaluated the influence of gene variant A>G rs20551 in EP300 in donor and/or recipient on clinical results after HLA-identical sibling allo-SCT. Patients with AA gene variant had a lower relapse incidence (31 vs 48%, P=0.025; odds ratio (OR)=1.6, P=0.05), attained better disease-free survival (AA: 53% vs AG+GG: 24%, P=0.001; OR=1.8, P=0.01), and better OS (AA: 53% vs AG+GG: 34%, P=0.001; OR=1.9, P=0.007). This beneficial association was more evident when AA gene variant was present in both donor and patient. In healthy individuals, AA gene variant was associated with lower IL2 production after a mitogenic stimuli, higher CD4+ cell response after CMV infection, and higher expression of innate immune genes (IRF-3 and MIF), cell cycle genes (AURKB, CCNA2 and CCNB1), lymphocyte survival genes (NFAT5 and SLC38A2), and with a lower expression of P53 compared with recessive GG gene variant. These findings suggest a beneficial effect of the AA gene variant in rs20551 on clinical outcome after allo-SCT.

Serial intestinal endoscopic examinations of patients with persistent diarrhea after allo-SCT.

Gastrointestinal (GI) GVHD after allo-SCT is diagnosed on the basis of symptoms and findings in endoscopic mucosal biopsy specimens. However, GI symptoms often persist despite treatment and whether a second endoscopy may be helpful in determining the most suitable therapy is not established. We identified 31 patients with persistent diarrhea who underwent more than one endoscopic study. All cases underwent serial microbiological stool analysis and CMV-detecting assays on serum and biopsies. Of the 31 initial GI biopsies, 20 (64.5%) were classified as GVHD, two (6.5%) as GVHD with CMV, four (13%) as non-CMV infection, and five (16%) as normal or unspecific. The second GI biopsies were diagnostic of GVHD in nine cases (29%), GVHD simultaneously with CMV infection in four (13%), regenerative changes post-GVHD in five (16%), CMV infection in four (13%), and normal or unspecific in nine (29%). In 22 of the 31 patients (71%), the histological findings of the second/third endoscopic biopsies differed from the findings of the first endoscopy and led to a therapy change in 77%. In conclusion, serial GI endoscopies are of reliable diagnostic value and can impact on therapeutic decision-making for patients with persistent diarrhea after allo-SCT.

Clinical utility of real-time polymerase chain reaction to quantify cytomegalovirus replication in allogeneic stem cell transplant recipients with different prevention strategies.

Cytomegalovirus (CMV) end-organ disease is a serious, frequent complication after allogenic stem cell transplantation (Allo-SCT). There are two prevention strategies: universal prophylaxis and preemptive therapy. Preemptive therapy is administered based on the results of sensitive techniques that detect the viral infection. We analyzed 41 peripheral blood Allo-SCT recipients: 34 received prophylaxis and seven preemptive treatment. Viral infections determined using real-time polymerase chain reaction (RT-PCR) assays occurred at an overall incidence of 65.8%. The viral loads quantified by RT-PCR were compared among the prophylaxis versus the preemptive group. Overall, the median viral load was significantly higher in the preemptive compared with the prophylaxis group (P=.002). Furthermore, within the first 100 days posttransplantation, viral load values were higher among patients undergoing preemptive therapy (P=.009).

Differences in cytomegalovirus replication quantified using quantitative polymerase chain reaction and antigenemia after allogeneic stem cell transplantation.

Fifty percent of allogeneic stem cell recipients develop cytomegalovirus (CMV) infection in the first 100 days posttransplantation. Various methods have been used to determine CMV infections, including antigenemia assay and real-time polymerase chain reaction (RT-PCR). Although antigenemia assay has been used more frequently, this technique is less sensitive than RT-PCR. In contrast, RT-PCR has a low positive predictive value for CMV end-organ disease. Cytomegalovirus infections were analyzed in 41 peripheral blood samples from allogeneic stem cell recipients using both antigenemia assay and RT-PCR; results were discordant in 36.6% of patients. Although the antigenemia assay detected CMV replication in 29.2% of cases, RT-PCR was positive in 65.8%. In 83.3% of patients, results detected using the antigenemia assay were delayed by a median (range) of 5 (2-20) weeks compared with positive RT-PCR results. Within the first 100 days posttransplantation, higher levels of viral replication measured using RT-PCR were observed in patients with vs without antigenemia. In addition, in patients with antigenemia, viral load was significantly higher before day 100 than after (P=.01 and P=.008, respectively) compared with those without antigenemia.

Evaluation of the pretransplantation phase of the hemopoietic stem cell program in a tertiary hospital.

INTRODUCTION: Therapeutic decisions and clinical events during the pretransplantation phase of stem cell transplantation (SCT) may influence survival, quality of life, and efficiency of health expenses. However, there is a lack of relevant published data. AIMS: The aims of this study were to identify reasons why the procedure was not performed and to know the waiting time for SCT candidates. PATIENTS AND METHODS: We collected pretransplantation data from 166 consecutive patients evaluated by the SCT Committee of a tertiary center between April 2005 and December 2006. RESULTS: One hundred fifty-two of 166 patients were referred for the first time. Additionally, 14 were reconsidered as candidates for a subsequent SCT due to relapse, graft failure, secondary malignancy, or a multiple-graft program. One hundred forty-one were accepted for transplantation, whereas 25 were not. At the time of analysis, 22 patients were still awaiting SCT, 8 were delayed because they required additional courses of treatment, and 32 were excluded because of death (34.4%), poor stem cell mobilization (21.9%), patient refusal (15.6%), relapse/progression (9.4%), comorbidity (6.3%), or absence of a donor (6.3%). The median time between inclusion in the program and transplantation was 3.6 months (range, 0.27-13.43), and 5.7 months (P < .05) for unrelated allogeneic transplantation. No significant differences were observed in the diagnosis or hospital of origin. CONCLUSIONS: SCT was not performed in 22% of transplant candidates, mainly due to death, insufficient stem cell mobilization, patient refusal, or disease progression/relapse. The median time between inclusion in the SCT program and transplantation was 3 months, but longer among the unrelated allogeneic transplantations.

Preemptive therapy for cytomegalovirus disease in allogeneic stem cell transplant recipients.

Cytomegalovirus (CMV) infection causes high morbidity and mortality among allogeneic stem cell transplant recipients. Preemptive therapy with oral valganciclovir or intravenous ganciclovir has replaced universal prophylaxis. We prospectively studied 19 consecutive adult recipients of allogeneic peripheral blood stem cell transplants from May 2005 through February 2007 to analyze the safety and efficacy of preemptive therapy for the treatment of CMV infection. The antigenemia test was persistently negative in 8 patients (42%) and positive at least once in 11 (58%). Eight patients were treated with oral valganciclovir on an outpatient basis and they all became CMV negative after the first week of treatment. The other 3 patients received intravenous ganciclovir and were also CMV negative after the first week of treatment. No patient abandoned treatment, no severe secondary toxicity was noted, and there was no CMV-associated mortality.

High rate of long-term survival for high-risk lymphoma patients treated with hematopoietic stem cell transplantation as consolidation or salvage therapy.

Patients with high-relapse-risk lymphomas or those relapsing after initial therapy have a limited probability of cure with conventional treatment. There is recent inconclusive evidence that, in such cases, intensification or salvage treatment with high-dose chemotherapy followed by hematopoietic stem cell transplantation (HSCT) increases the response rate and may improve survival. Nevertheless, published data on long-term follow-up of high-risk lymphoma patients treated with HSCT are scarce. We analyzed 101 consecutive patients receiving high-dose chemotherapy followed by HSCT after induction with standard chemotherapy. The median age was 38 years (range, 12-63 years). The diagnoses were Hodgkin's disease (n = 32), follicular lymphoma (n = 33), diffuse large B-cell lymphoma (n = 12), mantle cell lymphoma (n = 7), T-cell lymphoma (n = 14), and others (n = 3). Patients received either an autologous graft (n = 72) in first complete remission (1CR; n = 23) or in advanced stages (AS; n = 49), or an allogeneic graft (n = 29) in 1CR (n = 7) or in AS (n = 22). We concluded that transplant-related mortality was 2.7% for patients receiving an autologous HSCT and 27% for patients receiving an allogeneic HSCT. The main etiologies were graft-versus-host disease and infection in the allogeneic setting, and infection in the autologous setting. The probability of long-term (12-year) overall survival was 71%, higher than that described for high-relapse-risk lymphoma patients treated without HSCT and significantly better (P < .05) for patients who received the transplant in 1CR (89%) than in AS (65%). Finally, the probability of long-term survival was significantly better for patients treated with HSCT during the period from 2000-2007 (85%) compared with the period from 1989-1999 (72%).