Philippe Guardiola

TET2 mutation is an independent favorable prognostic factor in myelodysplastic syndromes (MDSs)

Oncogenic pathways underlying in the development of myelodysplastic syndromes (MDS) remain poorly characterized, but mutations of the ten-eleven translocation 2 (TET2) gene are frequently observed. In the present work, we evaluated the prognostic impact of TET2 mutations in MDS. Frameshift, nonsense, missense mutations, or defects in gene structure were identified in 22 (22.9%) of 96 patients (95% confidence interval [CI], 14.5-31.3 patients). Mutated and unmutated patients did not significantly differ in initial clinical or hematologic parameters. The 5-year OS was 76.9% (95% CI, 49.2%-91.3%) in mutated versus 18.3% (95% CI, 4.2%-41.1%) in unmutated patients (P = .005). The 3-year leukemia-free survival was 89.3% (95% CI, 63.1%-97.0%) in mutated versus 63.7% (95% CI, 48.2%-75.4%) in unmutated patients (P = .035). In univariate analysis (Cox proportional hazard model), the absence of TET2 mutation was associated with a 4.1-fold (95% CI, 1.4-12.0-fold) increased risk of death (P = .009). In multivariate analysis adjusted for age, International Prognostic Scoring System, and transfusion requirement, the presence of TET2 mutation remained an independent factor of favorable prognosis (hazard ratio, 5.2; 95% CI, 1.6-16.3; P = .005). These results indicate that TET2 mutations observed in approximately 20% of patients, irrespective of the World Health Organization or French-American-British subtype, represent a molecular marker for good prognosis in MDS.

Prolonged immune deficiency following allogeneic stem cell transplantation: risk factors and complications in adult patients.

To evaluate the long‐term immune reconstitution after allogeneic haematopoietic stem cell transplantation (SCT), we prospectively screened standard immune parameters in a series of 105 patients, at a median time of 15 months after SCT. Analysing lymphoid phenotypes, in vitro immune functions and immunoglobulin levels, we found that, more than 1 year post SCT, cellular and humoral immunity was still altered in a significant number of patients. CD4+ T cells were < 200/µl in one third of patients, and the CD4/CD8 ratio was still reversed in 78% of patients. Almost all patients showed positive T‐cell responses against mitogens, but antigen‐specific proliferation assays identified 20% to 80% of non‐responders. B‐cell counts were reconstituted in 61% of the patients, but levels of total immunoglobulins were still low in 59%. In multivariate analyses, human leucocyte antigen (HLA) disparity between donor and recipient and chronic graft‐versus‐host disease were the leading causes affecting immune reconstitution. Interestingly, cytomegalovirus (CMV) infections were strongly associated with normal CD8+ T‐cell counts. Studying the impact of impaired immune reconstitution on the rate of infections occurring in the 6 years following screening, we identified three parameters (low B‐cell count, inverted CD4/CD8 ratio, and negative response to tetanus toxin) as significant risk factors for developing such late infections.

Accelerated telomere shortening and telomerase activation in Fanconi's anaemia

Fanconis anaemia (FA) is an autosomal recessive disorder characterized by progressive bone marrow failure that often evolves towards acute leukaemia. FA also belongs to a group of chromosome instability diseases. Because telomeres are directly involved in chromosomal stability and in cell proliferation capacity, we examined telomere metabolism in peripheral blood mononuclear cells (PBMC). Telomere length was significantly shorter in 54 FA patient samples, compared to 51 controls (P<0.0001). In addition, mean telomere terminal restriction fragment lengths (TRF) in nine heterozygous patient samples did not differ from those of controls. In 14 samples from FA patients with severe aplastic anaemia (SFA), telomere length was significantly shorter than in 22 samples of age‐matched FA patients with moderate haematological abnormalities (NSFA) (P<0.001). However, no correlation was found between TRF length and the presence of bone marrow clonal abnormalities in 16 additional, separately analysed, patient samples. Sequential measurement of TRF in six FA patients showed an accelerated rate of telomere shortening. Accordingly, telomere shortening rate was inversely correlated with clinical status. Telomerase, the enzyme that counteracts telomere shortening, was 4.8‐fold more active in 25 FA patients than in 15 age‐matched healthy controls. A model for the FA disease process is proposed.

Second early allogeneic stem cell transplantations for graft failure in acute leukaemia, chronic myeloid leukaemia and aplastic anaemia

In this retrospective multicentre study, we analysed the results of 82 consecutive second early allogeneic transplants for primary (n = 28) or secondary (n = 54) graft failures performed between 1985 and 1997 in patients with acute leukaemia (n = 33), aplastic anaemia (n = 29) or chronic myeloid leukaemia (n = 20). HLA‐matched siblings were used in 64 cases. The same donors were used for both transplants in 56 cases and the first transplant was T‐cell depleted in 30 cases. The median age at transplant was 25 years and the median intertransplant time interval was 2 months. Estimates of the 3‐year overall survival and day 100 transplant‐related mortality were 30% and 53% respectively. A recipient age < 34 years at transplant, an intertransplant time interval ≥ 80 d and a positive recipient cytomegalovirus serology were predictors of a better outcome. The use of cyclosporin A (CsA) after second transplant had a dramatic impact on outcome, the best results being observed with CsA alone. The day 40 probability of neutrophil recovery was 73%. The use of peripheral blood progenitor cells (PBPCs) was associated with a higher and faster neutrophil recovery. Other factors associated with neutrophil recovery were an intertransplant time interval ≥ 80 d and a positive recipient cytomegalovirus serology. Therefore, second early allogeneic transplantation for graft failure is an effective treatment, especially if patients can receive CsA for graft‐versus‐host disease prevention and are retransplanted more than 80 d from first transplant.

IL-34 Induces the Differentiation of Human Monocytes into Immunosuppressive Macrophages. Antagonistic Effects of GM-CSF and IFNγ

IL-34 is a recently identified cytokine that signals via the M-CSF receptor and promotes monocyte survival. Depending on the environment, monocytes can differentiate into macrophages (Mφ) or dendritic cells (DC). A wide spectrum of Mφ and DC subsets, with distinct phenotypes and functions, has been described. To date, the phenotype of monocytes exposed to IL-34 remains unexplored. We report here that IL-34 induces the differentiation of monocytes into CD14high CD163high CD1a− Mφ (IL-34-Mφ). Upon LPS stimulation, IL-34-Mφ exhibit an IL-10high IL-12low M2 profile and express low levels of the costimulatory molecules CD80 and CD86. IL-34-Mφ exhibit poor T cell costimulatory properties, and have potent immunosuppressive properties (decrease of TCR-stimulated T cell proliferation). For all the parameters analyzed, IL-34-Mφ are phenotypically and functionally similar to M-CSF-Mφ. IL-34 appears as efficient as M-CSF in inducing the generation of immunosuppressive Mφ. Moreover, the generation of IL-34-Mφ is mediated through the M-CSF receptor, is independent of endogenous M-CSF consumption and is potentiated by IL-6. In an attempt to identify strategies to prevent a deleterious M2 cell accumulation in some pathological situations, we observed that IFNγ and GM-CSF prevent the generation of immunosuppressive Mφ induced by IL-34. IFNγ also switches established IL-34-Mφ into immunostimulatory Mφ. In conclusion, we demonstrate that IL-34 drives the differentiation of monocytes into immunosuppressive M2, in a manner similar to M-CSF, and that IFNγ and GM-CSF prevent this effect.

Allogeneic bone marrow transplantation for agnogenic myeloid metaplasia

Agnogenic myeloid metaplasia is a rare indication for allogeneic bone marrow transplantation (BMT). We have retrospectively studied 12 patients allografted for this disease within the French BMT group. Prior to BMT, the mean age was 40 years (range 14–49). Diagnosis was based on the Polycythaemia Vera Study Group criteria. Before BMT, 10 patients had been splenectomized, eight required transfusions, and four had received at least two lines of chemotherapy. Cyclophosphamide and total body irradiation was the main conditioning regimen used (n=8). The donor was an HLA‐identical sibling except in one case where there was one HLA‐DR mismatch. Acute graft‐versus‐host disease (GVHD) prophylaxis consisted of methotrexate and cyclosporine A. 11 patients engrafted with median times to achieve absolute neutrophil count > 0.5 × 109/l and platelet count > 50 × 109/l of 17 (range 12–44) and 29 (range 12–196) days respectively. One primary graft failure occurred. 10 patients developed grade II–IV acute GVHD, four developed extensive chronic GVHD. One patient relapsed 16 months post‐BMT and was untreated and well 14 months later. Three patients died from the BMT procedure. In May 1996 the median follow‐up was 25 months and the 4‐year overall and event‐free survivals were 71% and 59%, respectively. Thus, we conclude that extensive myelofibrosis is not associated with delayed engraftment, and that HLA‐identical sibling allogeneic BMT can be considered in a small proportion of patients with agnogenic myeloid metaplasia.

Dismal prognostic value of monosomal karyotype in elderly patients with acute myeloid leukemia: a GOELAMS study of 186 patients with unfavorable cytogenetic abnormalities

The prognosis of acute myeloid leukemia (AML) is very poor in elderly patients, especially in those classically defined as having unfavorable cytogenetics. The recent monosomal karyotype (MK) entity, defined as 2 or more autosomal monosomies or combination of 1 monosomy with structural abnormalities, has been reported to be associated with a worse outcome than the traditional complex karyotype (CK). In this retrospective study of 186 AML patients older than 60 years, the prognostic influence of MK was used to further stratify elderly patients with unfavorable cytogenetics. CK was observed in 129 patients (69%), and 110 exhibited abnormalities according to the definition of MK (59%). MK(+) patients had a complete response rate significantly lower than MK(-) patients: 37% vs 64% (P = .0008), and their 2-year overall survival was also decreased at 7% vs 22% (P < .0001). In multivariate analysis, MK appeared as the major independent prognostic factor related to complete remission achievement (odds ratio = 2.3; 95% confidence interval, 1-5.4, P = .05) and survival (hazard ratio = 1.7; 95% confidence interval, 1.1-2.5, P = .008). In the subgroup of 129 CK(+) patients, survival was dramatically decreased for MK(+) patients (8% vs 28% at P = .03). These results demonstrate that MK is a major independent factor of very poor prognosis in elderly AML.

Bone marrow transplantation for paroxysmal nocturnal haemoglobinuria.

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired clonal disorder of the haemopoietic stem cells for which the only curative treatment is bone marrow transplantation. There are few reports on the use of allogeneic transplantation for PNH, and nearly all of them include only a few patients. Between September 1978 and December 1997, 16 patients underwent marrow transplantation for PNH at the Hospital Saint Louis. The 5‐year survival rate for the 16 patients was 58 ± 13%. Two factors, an absolute neutrophil count >1.0 × 109/l and haemoglobin level >9 g/dl at transplant, were found to be statistically associated with a better outcome.

Abnormal telomere metabolism in Fanconi's anaemia correlates with genomic instability and the probability of developing severe aplastic anaemia.

Summary. Fanconis anaemia (FA) is an autosomal recessive disorder characterized by progressive bone marrow failure and a susceptibility to cancer. Haematopoietic stem cell transplantation is the only curative method for restoring normal haematopoiesis, and survival is improved if the transplant is carried out before severe complications occur. However, the evolution of FA is difficult to predict because of the absence of known prognostic factors and the unknown function of the genes involved. In studying 71 FA patients, a correlation was found between severe aplastic anaemia (SAA) and the individual annual telomere‐shortening rate (IATSR) in peripheral blood mononuclear cells (P < 10−3). Spontaneous apoptosis was highest in SAA patients or patients with high IATSR (> 200 bp/year) (P < 0·01, n = 18). Univariate and multivariate analyses showed that significant relative risks for evolution towards SAA were high IATSR (P < 10−4), and that a high number of chromosome breakages occurred in the presence of nitrogen mustard (P < 0·001). A high IATSR was also associated with an increased frequency of malignancy (P < 0·01). Thus, these biological parameters were related to the spontaneous evolution of FA and could be used as prognostic factors. These data indicated that telomeres might play a role in the evolution of bone marrow failure and malignant transformation in FA.

Allogeneic bone marrow transplantation for acute myeloblastic leukaemia in remission: risk factors for long-term morbidity and mortality

Summary:In this single-centre retrospective study, we analysed risk factors for nonrelapse long-term morbidity and mortality in patients with acute myeloblastic leukaemia (AML) who had undergone allogeneic transplantation. A total of 112 patients with de novo AML in first complete remission (CR1), n=90 or second complete remission (CR2, n=22) who received un-manipulated bone marrow grafts from human leukocyte antigen identical siblings between January 1985 and August 2000 were included. Of these, 97 patients alive and disease-free for at least 100 days after transplant were selected for the purpose of this long-term analysis. The use of an intensified conditioning regimen, Gram-negative bacteriaemia before transplantation, year of transplantation and number of pretransplant chemotherapy courses for patients in CR1 significantly affected the 7-year event-free survival which was 57%. 7-year transplant-related mortality TRM was 22%. Significant predictors for TRM were: bacterial infections before transplantation, major ABO blood group incompatibility, late severe bacterial infections, and chronic (graft-versus-host disease) GvHD. Predictive factors for late severe bacterial infections were infections before transplant, total body irradiation and GvHD. Incidence and risk factors for other late events including, chronic GvHD, late infections, osteonecrosis, cataract, endocrine- cardiac- and lung-complications, cancer and performance status at last follow-up were also studied. The analysis strongly suggests that the combination of pretransplant factors such as chemotherapy and conditioning, and posttransplant factors such as chronic GvHD had a major impact on late nonrelapse morbidity and mortality.