Yosr Hicheri

CD4+CD25+ Regulatory T Cell Depletion Improves the Graft-Versus-Tumor Effect of Donor Lymphocytes After Allogeneic Hematopoietic Stem Cell Transplantation

Immunological effects of donor lymphocyte infusion for treatment of recurrent malignancy after allogeneic hematopoietic cell transplantation can be enhanced by depleting T regulatory cells in the infused cells and in the recipient. Regulatory T Cells Interfere with Graft-Versus-Tumor Effects Patients search for organ donors who are close genetic matches to avoid immune reactions. But sometimes a little immune activation is a good thing. Hematopoietic stem cells in the form of bone marrow are often used to treat blood cancers, and the donated cells not only engraft in bone to provide a source of healthy blood cells but also contain T cells that attack and destroy any remaining cancerous cells. This graft-versus-tumor effect is also harnessed when such patients suffer a relapse and donor T cells are infused into the patient. These infusions often fail to quell the malignancy, however. The reason for failure, Maury et al. have now shown, is that the donor cells can often include regulatory T cells (Tregs), a class of T cells that dampens the immune response. Removing these cells before the infusion markedly improved the graft-versus-tumor effect and the patients’ survival. The beneficial graft-versus-tumor effect of transplantation can be accompanied by the not-so-desirable graft-versus-host disease. Like the transplanted T cells that perceive cancer cells as foreign, T cells can also attack the host’s skin, liver, intestinal lining, and other internal organs—a condition that is serious but can be treated. The authors of this study used the presence of graft-versus-host disease as a sign that there were active, functioning T cells that also provided graft-versus-tumor effects. They treated 17 patients with relapsed blood cancer who had previously received an infusion of lymphocytes and had neither clinical manifestations of graft-versus-host disease nor control of their malignancy. After receiving a new infusion of lymphocytes from which the Tregs had been removed, two of the patients developed graft-versus-host disease for the first time in their transplant history. Hypothesizing that this low rate of response was a result of Treg cells present in the recipient, they treated four of the patients who needed more infusions with the same Treg-depleted cells but now infused them immediately after recipient Tregs were eliminated with lymphopdepletive chemotherapy. These four patients, all of whom had Hodgkin’s lymphoma, reacted to the infused cells by developing graft-versus-host disease, a sign that the infused cells were likely attacking the tumor cells as well. When the whole group was assessed 1 year after treatment, the patients who had experienced a graft-versus-host reaction after cell infusion were found to have survived longer, likely a result of successful immune control of the cancer cells by the infused Treg-depleted lymphocytes. This preliminary study shows that depleting donor lymphocytes of inhibitory regulatory T cells can be a safe and effective way to free active T cells from inhibition so that they can fight cancer cells in the recipient. Further studies are needed, but this seemingly inappropriate encouragement of immune reactions in transplant recipients may prove a boon to patients with blood cancers. Donor T cells play a pivotal role in the graft-versus-tumor effect after allogeneic hematopoietic stem cell transplantation. Regulatory T cells (Tregs) may reduce alloreactivity, the major component of the graft-versus-tumor effect. In the setting of donor lymphocyte infusion after hematopoietic stem cell transplantation, we postulated that Treg depletion could improve alloreactivity and likewise the graft-versus-tumor effect of donor T cells. The safety and efficacy of Treg-depleted donor lymphocyte infusion was studied in 17 adult patients with malignancy relapse after hematopoietic stem cell transplantation. All but one had previously failed to respond to at least one standard donor lymphocyte infusion, and none had experienced graft-versus-host disease. Two of the 17 patients developed graft-versus-host disease after their first Treg-depleted donor lymphocyte infusion and experienced a long-term remission of their malignancy. Four of the 15 patients who did not respond after a first Treg-depleted donor lymphocyte infusion received a second Treg-depleted donor lymphocyte infusion combined with lymphodepleting chemotherapy aimed to also eliminate recipient Tregs. All four developed acute-like graft-versus-host disease that was associated with a partial or complete and durable remission. In the whole cohort, graft-versus-host disease induction through Treg depletion was associated with improved survival. These results suggest that Treg-depleted donor lymphocyte infusion is a safe, feasible approach that induces graft-versus-host or graft-versus-tumor effects in alloreactivity-resistant patients. In patients not responding to this approach, the combination of chemotherapy-induced lymphodepletion of the recipient synergizes with the effect of Treg-depleted donor lymphocyte infusion. These findings offer a rational therapeutic approach for cancer cellular immunotherapy.

Low prevalence of resistance to azoles in Aspergillus fumigatus in a French cohort of patients treated for haematological malignancies

OBJECTIVES An increase in invasive aspergillosis (IA) due to azole-resistant Aspergillus fumigatus isolates has been reported for 10 years. Our study aimed to estimate the prevalence of azole resistance in isolates prospectively collected in patients with haematological diseases. METHODS One hundred and eighteen isolates were collected from 89 consecutive patients over 4 years. Fifty-one patients had proven or probable IA. Species identification was ascertained based on β-tubulin gene sequencing. The MICs of azole drugs were determined using Etest(®), and the cyp51A gene and its promoter were sequenced to detect mutations. RESULTS All isolates were identified as A. fumigatus and all of them but one had itraconazole and voriconazole MICs of ≤ 2 mg/L and posaconazole MICs of ≤ 0.25 mg/L. An isolate for which the itraconazole MIC was high (itraconazole MIC = 16 mg/L; voriconazole MIC = 0.38 mg/L; and posaconazole MIC = 0.25 mg/L) was recovered from a patient naive to azole treatment and had a new G432S substitution. To establish whether this mutation existed in other isolates, the 1426-2025 bp cyp51A locus was sequenced for all. G432S was not found. CONCLUSIONS In A. fumigatus, the prevalence of azole resistance is currently low in the haematological population in the Paris area. Surveillance programmes for azole resistance to adapt antifungal treatments are warranted for clinical isolates of A. fumigatus.

Correlation between galactomannan antigen levels in serum and neutrophil counts in haematological patients with invasive aspergillosis

The detection of circulating galactomannan (GM) in serum samples is an important step in the diagnosis of invasive aspergillosis (IA). The assay has been mainly explored in neutropenic patients, and is now used to monitor patients at high risk for IA. However, the performance of the assay varies greatly among studies. The objective of this study was to explore the impact of the neutrophil count on the GM serum index at the time of IA diagnosis. Ninety-nine episodes of proven or probable, microbiologically documented IA in 91 patients with haematological malignancies were studied retrospectively. Three groups were identified: groups 1-3, with <100 polymorphonuclear neutrophils (PMN)/mm(3) (n = 18), between 100 and 500 PMN/mm(3) (n = 21), or >500 PMN/mm(3) (n = 60), respectively. The mean GM index was significantly higher in group 1 than in the other groups (p <0.05). This finding did not change after stratifying the analysis with regard to the use of antibiotics likely to give false-positive GM results or with regard to treatment effective against fungi before the diagnosis of IA. This finding could be considered in the routine use of the GM antigenaemia test in non-neutropenic patients; a negative result or a low GM index should not eliminate the diagnosis of IA. This limitation calls for other microbiological tests, including analysis of bronchoalveolar lavage fluid, to establish a definitive diagnosis of IA.

Impact of invasive fungal disease on the chemotherapy schedule and event-free survival in acute leukemia patients who survived fungal disease: a case-control study

Patients with acute leukemia who initially survive invasive fungal disease must receive chemotherapy or go on to transplant. Many centers change subsequent chemotherapy to decrease the risk of fungal reactivation. This case-control study compared acute leukemia patients (n=28) who developed a proven or probable fungal disease and survived four weeks later, to patients who did not (n=78), and assessed the impact of fungal disease on the chemotherapy regimens, and overall and event-free survival. Chemotherapy changes (i.e. delays, dose-reduction) were more frequent in the fungal (68%) than in the control group (24%) (P<0.001). Although there was no difference in overall and event-free survival between groups, they were both lower for proven fungal disease cases when compared to controls (HR 2.4, 95% CI 1.1–1.5, and HR 2.9, 95% CI 1.4–5.6, respectively). Patients with invasive fungal disease, even though they initially survive, undergo significant changes to their chemotherapy therapy. This impacts on the survival of patients with proven fungal disease.

Scedosporium prolificans: an emerging pathogen in France?

For the last ten years, non-Aspergillus mold species have been increasingly involved in human invasive infections, probably as a consequence of more intense immunosuppression and prolonged patient survival, and of selective pressure since antifungal agents are currently used for prophylaxis or therapy. Scedosporium prolificans, one of these emerging fungi, has been isolated in a broad spectrum of clinical presentations in humans, including respiratory-tract colonization, superficial or locally invasive infections, and disseminated infections in immunocompromised patients. Here, we report the recent emergence of invasive infections due to S. prolificans in France, and describe four new cases diagnosed during the last six years. Only one disseminated scedosporiosis has been reported before this in France, in 1994. Three out of our four cases were breakthrough infections in immunocompromised patients receiving posaconazole or voriconazole therapy. The aims of the present review were thus to gain a better understanding of scedosporiosis epidemiology and clinical features, and to review recent advances in multimodal management of these infections, including surgery, recovery and/or enhancement of immunity, and antifungal combinations, especially voriconazole plus terbinafine.

Performance of serum biomarkers for the early detection of invasive aspergillosis in febrile, neutropenic patients: a multi-state model.

Background The performance of serum biomarkers for the early detection of invasive aspergillosis expectedly depends on the timing of test results relative to the empirical administration of antifungal therapy during neutropenia, although a dynamic evaluation framework is lacking. Methods We developed a multi-state model describing simultaneously the likelihood of empirical antifungal therapy and the risk of invasive aspergillosis during neutropenia. We evaluated whether the first positive test result with a biomarker is an independent predictor of invasive aspergillosis when both diagnostic information used to treat and risk factors of developing invasive aspergillosis are taken into account over time. We applied the multi-state model to a homogeneous cohort of 185 high-risk patients with acute myeloid leukemia. Patients were prospectively screened for galactomannan antigenemia twice a week for immediate treatment decision; 2,214 serum samples were collected on the same days and blindly assessed for (1->3)- β-D-glucan antigenemia and a quantitative PCR assay targeting a mitochondrial locus. Results The usual evaluation framework of biomarker performance was unable to distinguish clinical benefits of β-glucan or PCR assays. The multi-state model evidenced that the risk of invasive aspergillosis is a complex time function of neutropenia duration and risk management. The quantitative PCR assay accelerated the early detection of invasive aspergillosis (P = .010), independently of other diagnostic information used to treat, while β-glucan assay did not (P = .53). Conclusions The performance of serum biomarkers for the early detection of invasive aspergillosis is better apprehended by the evaluation of time-varying predictors in a multi-state model. Our results provide strong rationale for prospective studies testing a preemptive antifungal therapy, guided by clinical, radiological, and bi-weekly blood screening with galactomannan antigenemia and a standardized quantitative PCR assay.

Daily practice management of myelodysplastic syndromes in France: data from 907 patients in a one-week cross-sectional study by the Groupe Francophone des Myelodysplasies.

Background There is little published information on the everyday clinical management of myelodysplastic syndromes in real world practice. Design and Methods We conducted a cross-sectional study of all patients with myelodysplastic syndromes attending 74 French centers in a 1-week period for inpatient admission, day-hospital care or outpatient visits. Results Nine hundred and seven patients were included; 67.3% had lower-risk myelodysplastic syndromes (International Prognostic Scoring System: low or intermediate-1). Karyotype had been analyzed in 82.5% of the cases and was more often of intermediate or poor risk in patients under 65 years old compared with those who were older. Red blood cell transfusions accounted for as many as 31.4% of the admissions. Endogenous erythropoietin level was less than 500 IU/L in 88% of the patients tested. Erythroid stimulating agents had been or were being used in 36.8% of the lower risk patients, iron chelation in 31% of lower risk patients requiring red blood cell transfusions and lenalidomide in 41% of lower risk patients with del 5q. High-dose chemotherapy, hypomethylating agents, low dose cytarabine and allogeneic stem cell transplantation had been or were being used in 14.8%, 31.1%, 8.8% and 5.1%, respectively, of higher-risk patients. Conclusions Karyotype is now assessed in most patients with myelodysplastic syndromes, and patients under 65 years old may have more aggressive disease. Apart from erythroid-stimulating agents and, in higher-risk myelodysplastic syndromes, hypomethylating agents, specific treatments are used in a minority of patients with myelodysplastic syndromes and red blood cell transfusions still represent the major reason for hospital admission.

Is there still a place for myeloablative regimen to transplant young adults with sickle cell disease

To the editor: We have read with great interest the comprehensive and detailed review on hematopoietic stem cell transplantation (HSCT) for sickle cell disease (SCD) published by Hsieh et al in a recent issue of the journal.[1][1] As emphasized by the authors, allogeneic HSCT is currently the only

The epidemiology of invasive Streptococcus pneumoniae infections in onco-haematology and haematopoietic stem cell transplant patients in France. Are the serotypes covered by the available anti-pneumococcal vaccines?

The pneumococcal antigens contained in the polysaccharide (PPV23) and conjugate (7-valent, PCV7; 13-valent, PCV13) vaccines have been chosen since they represent the serotypes that more frequently cause invasive pneumococcal disease. Whether these vaccines cover the serotypes most frequently isolated in haematology patients is unclear. The serotype distribution among Streptococcus pneumoniae in 25 consecutive pneumococcal infections that occurred over the last 3 years in two French haematology departments was investigated. The pneumococcal vaccines PCV7, PCV13 and PPV23 were found to cover 76, 84 and 92%, respectively, of the serotypes found.

Donor regulatory T cells identified by FoxP3 expression but also by the membranous CD4+CD127low/neg phenotype influence graft-versus-tumor effect after donor lymphocyte infusion.

Regulatory T cells (Treg) play a pivotal role in the control of graft-versus-host disease (GVHD) and might also influence the graft-versus-tumor effect after allogeneic stem cell transplantation. We assessed this role after donor lymphocyte infusions (DLIs) by quantifying Treg in DLI products, using the CD25, Foxp3 but also the recently identified CD127 Treg markers. Compared with others, patients in durable complete remission of their malignancy after DLI had received a lower number of FoxP3+CD25+, FoxP3+CD127low/neg, or CD4+CD127low/neg Treg cells (P=0.04). The CD4+CD127low/neg Treg content of DLI remained significantly correlated with the hematologic response in multivariate analysis (P=0.05). Treg may thus inhibit graft-versus-tumor effect after DLI, a setting where the antitumoral effect observed is only driven by T-cell–mediated cytotoxicity, independently of any other associated treatment. In comparison with the intracytoplasmic Foxp3 marker, the membranous CD4+CD127low/neg phenotype of Treg could be particularly relevant to manipulate this cell-population, to increase the antitumoral response in strategies of allogeneic or autologous immunotherapy.