The immune receptor Trem1 cooperates with diminished DNA damage response to induce preleukemic stem cell expansion.

Fanconi anemia (FA) is an inherited bone marrow failure syndrome with extremely high risk of leukemic transformation. Here we investigate the relationship between DNA damage response (DDR) and leukemogenesis using the Fanca knockout mouse model. We found that chronic exposure of the Fanca-/- hematopoietic stem cells to DNA crosslinking agent mitomycin C in vivo leads to diminished DDR, and the emergence/expansion of pre-leukemia stem cells (pre-LSCs). Surprisingly, although genetic correction of Fanca deficiency in the pre-LSCs restores DDR and reduces genomic instability, but fails to prevent pre-LSC expansion or delay leukemia development in irradiated recipients. Furthermore, we identified transcription program underlying dysregulated DDR and cell migration, myeloid proliferation, and immune response in the Fanca-/- pre-LSCs. Forced expression of the downregulated DNA repair genes, Rad51c or Trp53i13, in the Fanca-/- pre-LSCs partially rescues DDR but has no effect on leukemia, whereas shRNA knockdown of the upregulated immune receptor genes Trem1 or Pilrb improves leukemia-related survival, but not DDR or genomic instability. Furthermore, Trem1 cooperates with diminished DDR in vivo to promote Fanca-/- pre-LSC expansion and leukemia development. Our study implicates diminishing DDR as a root cause of FA leukemogenesis, which subsequently collaborates with other signaling pathways for leukemogenic transformation.

Survival, prognostic factors and rates of leukemic transformation in 381 untreated patients with MDS and del(5q): a multicenter study.

Myelodysplastic syndromes (MDS) with del(5q) are considered to have a benign course of the disease. In order to address the issue of the propensity of those patients to progress to acute myeloid leukemia (AML), data on 381 untreated patients with MDS and del(5q) characterized by low or intermediate I International Prognostic Scoring System (IPSS) risk score were collected from nine centers and registries. Median survival of the entire group was 74 months. Transfusion-dependent patients had a median survival of 44 months vs 97 months for transfusion-independent patients (P<0.0001). Transfusion need at diagnosis was the most important patient characteristic for survival. Of the 381 patients, 48 (12.6%) progressed to AML. The cumulative progression rate calculated using the Kaplan-Meier method was 4.9% at 2 years and 17.6% at 5 years. Factors associated with the risk of AML transformation were high-risk World Health Organization adapted Prognostic Scoring System (WPSS) score, marrow blast count >5% and red-cell transfusion dependency at diagnosis. In conclusion, patients with MDS and del(5q) are facing a considerable risk of AML transformation. More detailed cytogenetic and molecular studies may help to identify the patients at risk of progression.

Histological and cytogenetic characterization of bone marrow in relation to prognosis and diagnosis of myelodysplastic syndromes.

Bone marrow (BM) histology of 102 myelodysplastic syndromes (MDS) patients was analyzed retrospectively. All the cases were reclassified according to the World Health Organization (WHO) classification. Karyotype study was conducted for all except one. Fifteen of the MDS cases were hypoplastic. The cellularity in bone marrow histology is sometimes ineffective in the differential diagnosis of MDS and aplastic anemia (AA). Nonetheless, a marked decrease in the number of megakaryocytes (average, 0.3/mm(2); range, 0-2/mm(2)) even in the hyperplastic foci of the marrow of AA was the most important histological feature differentiating AA from MDS, whereas the number of megakaryocytes increased in most MDS cases (44/mm(2); range, 1-240/mm(2)) and also in hypoplastic MDS (14/mm(2); range, 8-26/mm(2)). Hyperplastic marrow had a significantly high frequency of progress to acute myeloid leukemia (AML) and hypoplastic MDS had a lower rate of progress to AML. Severe myelofibrosis had a significantly poor prognosis. An increase in CD34-positive cells in MDS indicated a high rate of progress to AML. As for the patients with refractory cytopenia with multilineage dysplasia (RCMD; the new category under the WHO classification), the increased number of megakaryocytes was correlated with poor prognosis.

Childhood myelodysplasia.

The clinical data and hematological features of 29 children, under the age of 12 years, with primary myelodysplasia are presented. The diagnosis was made using the FAB (French-American-British) Cooperative Group criteria. There were 24 males and 5 females aged 4 months to 12 years (median 2.5 years) with marked male preponderance. Childhood myelodysplasia constituted 16% of all hematological malignancies and 36.7% of acute myeloid leukemias. The median duration of symptoms prior to diagnosis was 3 months. There were 15 cases of refractory anemia, one of refractory anemia with excess blasts, 3 of refractory anemia with excess blasts in transformation and 10 cases of chronic myelomonocytic leukemia. Five patients evolved to acute myeloid and 4 to acute lymphatic leukemia. The median duration of preleukemic phase in these patients was 7 months (range 4-29 months). The overall mean survival was short (5-9 months) in all the subgroups. Besides supportive therapy in most patients, two patients were treated with etoposide, one with alfa interferon 2b and one with high dose methylprednisolone. Our results show that myelodysplasia is not infrequent in children. The disease has an aggressive clinical course and may evolve into acute leukemia.

Clinical course of human T-lymphotropic virus type I carriers with molecularly detectable monoclonal proliferation of T lymphocytes: defining a low- and high-risk population.

To characterize the prodromal phase of adult T-cell leukemia (ATL), a prospective follow-up study was conducted on 50 carriers in a putative pre-ATL state. This state was defined by the presence of molecularly-detectable monoclonal proliferation of human T-lymphotropic virus type I (HTLV-I)-infected T lymphocytes, and the absence of clinical symptoms of leukemia. The median observation time was 50 months. The pre-ATL subjects were divided into two groups according to initial white blood cell (WBC) counts: group A, those with a normal WBC count (9,000/microL) (n = 30), and group B, those with an increased WBC count (9,000 to 15,000) (n = 20). Comparisons were made between the two groups and with a group of 25 patients with chronic ATL (group C) who had WBC counts of more than 15,000. Significant differences in survival rate were found between groups A and B (10-year survival 65.7%) and group C (32.8%) (P < .01), and between group A (10-year survival 90.0%) and group B (52.1%) (P < .05). The incidence of transformation to overt ATL was 10% (3 of 30) in group A and 50% (10 of 20) in group B (P < .01). In six transformed cases (one in A and five in B) we found exactly the same integration sites in pre-ATL and overt ATL phases, confirming the multistep leukemogenesis hypothesized for this disease. However, the pre-ATL subjects could be divided into two distinct prognostic groups based on the initial WBC count; those with good and those with poor prognosis. Although the 10% transformation rate (2.5% annually) in group A seemed to be extremely high compared with that in the general population of HTLV-I carriers (around 0.06% to 0.4% annually), the majority of group A subjects and some in group B showed stable clinical courses without transformation. Further, development of ATL was not observed in four group A subjects with HTLV-I-associated myelopathy (HAM), which is rarely associated with ATL. We propose to call this group of rather benign HTLV-I carriers "HTLV-I carriers with monoclonal proliferation of T lymphocytes (HCMPT)." Thus far we have been unable to identify reliable parameters other than WBC counts that prospectively distinguish HCMPT from the true pre-ATL state, in which there is a high probability of developing ATL. Further clinical and biologic approaches should elucidate the natural history of the HTLV-I carrier state and early events in ATL leukemogenesis.

Genetic lesions in preleukemia.

The incidence of genetic abnormalities have been investigated in a variety of preleukaemic states RAS and FMS oncogene, p53 suppressor gene mutations and monoclonality in myelodysplastic syndromes (MDS), a paradigm for pre-leukemias have been observed. Other patients at risk of developing either secondary leukaemia or evolving into leukaemia have been similarly studied including haematologically normal patients in remission from lymphoma. Time from treatment to detection of genetic abnormalities is a significant factor in some of these patients which is consistent with the expansion of an abnormal clone. A case of non-dysplastic MDS has been identified with a 7q-karyotypic abnormality typical of therapy related MDS, abnormal progenitor growth and RAS mutations but with normal clinical features. Normal individuals have also been under investigation and found to have a low incidence of proto-oncogene mutations. A prospective study should enable us to determine if these parameters are indeed prognostic indicators.

Prognostic significance of single chromosome abnormalities in preleukemic states.

Clinical outcome was evaluated in 43 patients with a myelodysplastic syndrome or myeloproliferative disorder and a bone marrow clone containing a single chromosome abnormality: monosomy 7/del(7q), trisomy 8, i(17q), del(5q), del(20q), or a t(2;11). Those with one of the first three abnormalities (22 patients) had shorter survival, more frequent progression to leukemia, and less response to treatment with 13-Cis-retinoic acid than did those in the latter three groups (21 patients). Additional data on these subgroups of preleukemic patients may confirm the prognostic value of such karyotypic information.

Clinical-cytogenetic correlations in myelodysplasia (preleukemia).

Cytogenetic studies detected abnormalities in 107 (43%) of the 247 patients in this series. Some degree of overt clinical progression occurred in 55 patients (22%), this being 29% of those patients with cytogenetic abnormalities and 17% of those with normal chromosomes. The presence and complexity of a clonal cytogenetic abnormality correlated with shorter survival. In each clone category of a complexity classification (simple, complex, very complex), patients with some normal cells appeared to have better survival than those with none. In multiple regression analyses, the prognostic value of chromosomes was independent of (and second in importance to) the FAB type of myelodysplastic syndrome (MDS) whichever chromosome classification was used. Patients with refractory anemia (RA) had the lowest incidence of chromosome abnormalities and no cases were found to have only abnormal cells (AA). A greater proportion of patients with refractory anemia with an excess of blasts (RAEB) and RAEB in transformation (RAEB-t) had clonal abnormalities. Morphology alone is not at present able to distinguish between RA or refractory anemia with ringed sideroblasts and similar disorders that may not be MDS in the strict sense. Demonstration of a clonal cytogenetic abnormality remains a positive indication of the presence of the neoplastic nature of the disease.

Cytogenetic characteristics of therapy-related acute nonlymphocytic leukaemia, preleukaemia and acute myeloproliferative syndrome: correlation with clinical data for 61 consecutive cases.

Cytogenetic studies were performed on a new series of 23 patients with therapy-related acute non-lymphocytic leukaemia, preleukaemia or an acute myeloproliferative syndrome. In our total series of now 61 cases studied by chromosome banding techniques, at least one of the abnormalities -7, 5q-, 7q- or -5 or some related unbalanced translocations, primarily -7, +t(1q7p), was observed in 40 patients. The critical region for the deletions of chromosome no. 5 comprises bands 5q22 to 5q33 and of chromosome no. 7 bands distal to 7q22. The third most frequently involved chromosome was no. 21, rearranged at band 21q22 in the three patients with 21q+ and in one patient with 21q-. An i(21q) was observed in two patients, a -21 in four patients and a -22, +t(21q22q) and a -5, -21, +t(5p21q) in one patient each. Other characteristic abnormalities included total loss or rearrangements of the short arm of chromosome no. 17, observed in nine patients. One patient had a -12, three others had rearrangements resulting in a partial or total loss of the short arm of chromosome no. 12. A 19q+ with translocation to band 19q13 was observed in three cases, a -18 in three cases and a 3p- in four cases. Thirty-one patients with multiple chromosome aberrations experienced a significantly shorter survival as compared to 13 patients with a normal karyotype (P = 0.02) and 17 patients with one single chromosome aberration (P less than 0.01).

Treatment of preleukemic syndromes with continuous intravenous infusion of low-dose cytosine arabinoside.

Preleukemic syndromes compose a group of acquired bone marrow disorders characterized by dysplastic maturation of hematopoietic cells and peripheral blood cytopenias. These syndromes have been generally considered untreatable. We administered low doses of cytosine arabinoside by continuous infusion for 14 to 21 days (20 mg/m2/d) to 16 patients with preleukemia in various stages of evolution to acute leukemia. Steady state plasma cytosine arabinoside levels ranged from 41.8 to 64.2 nmol/L. Eleven patients demonstrated marked improvement in hematopoiesis and loss of transfusion requirements for periods ranging from two to 27 + months. All but one responding patient developed recurrent pancytopenia, but additional responses to low-dose cytosine arabinoside were achieved in five of five retreated patients. Median overall survival time is 12 months for the 11 responding cases, and nine months for nonresponders. The major toxicity of low-dose cytosine arabinoside is myelosuppression, and most patients required platelet transfusion support and administration of antibiotics. Chromosome analyses demonstrated evolution to a new clone of hematopoietic cells in three patients, and persistence of the same abnormal clone in another patient. These results suggest that low-dose cytosine arabinoside therapy may result in improved hematopoiesis by promoting maturation or by selecting new stem cell clones. Low-dose cytosine arabinoside therapy thus deserves further evaluation both as a single agent and in combination with other agents in the treatment of myelodysplastic syndromes.

Myelodysplastic syndromes: a scoring system with prognostic significance.

141 patients with MDS were classified according to the FAB criteria and followed up for a period of 4-192 months. It was recognized that patients with RAEBT had a uniformly poor prognosis. However, there was a wide variation in survival among the other subgroups. A score of 1 was assigned to each of the following presenting haematological features: bone marrow blasts greater than or equal to 5%, platelets less than or equal to 100 X 10(9)/l, neutrophils less than or equal to 2.5 X 10(9)/l and Hb less than or equal to 10.0 g/dl. Therefore the score for each patient ranged between 0 and 4. There were no statistically significant differences between those patients who scored 0 or 1, or between those who scored 2 and 3. Therefore patients were put into three groups: Group A (score 0 or 1), Group B (score 2 or 3), Group C (score 4). The differences in survival between each of the three groups are highly significant (P less than 0.00001). This system further separates patients with RA, RAS, RAEB into good and bad prognostic groups. This study also confirms that deaths due to cytopenias are more common than those due to transformation to AML. The use of this scoring system in conjunction with the FAB criteria for MDS should serve as a prognostic tool on which to base treatment.

Preleukemic syndrome in elderly patients--report of 11 cases.

The preleukemic syndrome occurs mainly after middle age. We report 11 patients, aged 62 to 92 years, who presented with weakness, fatigue, malaise and pallor. Eight patients died; survival from the time of diagnosis was between 2 and 21 months. Two of them developed acute myelomonocytic leukemia. A third patient developed Philadelphia chromosome-negative chronic myeloid leukemia within 9 months. Serum unsaturated B12 binding capacity and transcobalamin I were elevated in this patient, preceding the transformation to chronic myeloid leukemia. Five other patients died from sepsis or pneumonia. All patients were anemic, and 10 were leukopenic. Bone marrow was hypocellular in 1 and hypercellular in 10 cases. Chromosomal studies were performed in five patients, with three showing abnormal findings: 47xx, trisomy 8 and a tetraploid karyotype 92xxyy5q-. No cytotoxic treatment should be given during the preleukemic phase until transformation to acute leukemia occurs. Since preleukemic patients are very susceptible to infections, early diagnosis of the condition is important, as is supportive care in the case of surgery.

[Prognostic factors in myelodysplastic syndromes: analysis of 72 cases]. / Prognostische Faktoren bei myelodysplastischen syndromen (MDS): eine Analyse von 72 Fällen.

72 patients were diagnosed as suffering from myelodysplastic syndromes (MDS) according to the FAB classification: 16 patients with refractory anaemia (RA), 11 patients with acquired idiopathic sideroblastic anaemia (AISA), 14 patients with refractory anaemia with an excess of blast cells (RAEB), 7 patients with RAEB in transformation (RAEB/t) and 24 patients with chronic myelomonocytic leukaemia (CMML). The duration of the preleukaemic phase was between 2 and 189 months (median: 15 months); RAEB in transformation and CMML showed a median phase of less than 12 months. Transformation into acute leukaemia (AL) occurred in 46 patients (64%). Of the clinical signs only thrombocytopenia was a significant poor prognostic factor (p less than 0.01). Cytogenetic studies were made in 31 patients. 14 had clonal aneuploidy: these patients had a higher risk of AL, but not a significantly shorter preleukaemic phase (p greater than 0.1). Stem cell cultures (CFUc) were carried out in 31 patients. Patients without colony growth or only cluster growth showed a high incidence (10/11 and 8/8) of transformation into AL; preleukaemic phases were significantly shorter than in patients with normal colony growth or cluster + colony growth in all FAB subgroups (p less than 0.001). The bone marrow blast cell count was indirectly proportional to the duration of the preleukaemic phase: thrombocytopenia, cytogenic aberrations and failure of in vitro colony growth are additional poor prognostic factors in MDS.

Modifications in the classification of primary myelodysplastic syndromes: the addition of a scoring system.

A retrospective series of patients with the primary myelodysplastic syndrome has been reviewed and the survival updated. A scoring system is proposed that has advantages in predicting survival outcome. The importance of either dysmegakaryocytopoiesis or dysgranulocytopoiesis is emphasized because of its prognostic impact on leukaemic progression. Over 50 per cent of the patients die from either acute leukaemia or consequences of defective marrow production of granulocytes and platelets. Although only a few cases were included, the RAEB-T group has a very poor outcome and appears much closer to FAB M2 in biologic behaviour than RAEB. Both the criteria for the FAB subtypes and the scoring system can be applied easily in each case of myelodysplasia. Of the 56 patients only 9 were still alive as of April, 1984. Eight of these were in the RA-S and RA categories (or using the scoring system grouping 7 were group 1). All of the 16 patients who progressed to overt AML died within 4 weeks, and none was treated with chemotherapy. Of the remaining 31 patients, half died as a result of infection and/or haemorrhage and the remainder from apparently unrelated causes (cardiovascular, carcinoma, renal failure). These latter deaths are not surprising in light of the median age of 72 years.

Leukemogenesis by methylnitrosourea in BDF1 mice. The origin of transplantable cells and the activity of the natural killer cells during the preleukemic period.

BDF1 mice injected with methylnitrosourea (MNU, 50 mg/kg) developed T cell leukemias within 9-35 weeks (median induction time 18 weeks). Leukemic cells, determined by transplantation, were found 2-5 weeks before the death of the animals. Natural killer (NK) cell activity in the spleen and peritoneal exudate cells was studied using YAC-1 cells as targets. MNU-treated mice showed reduced lytic activity with or without stimulation by Corynebacterium parvum. NK activity was essentially the same in mice with and without transplantable leukemic cells. No correlation could be demonstrated between the degree of NK cell depression, as studied in the spleen after splenectomy, and the survival time of individual mice.

Acute nonlymphocytic leukemia, preleukemia, and acute myeloproliferative syndrome secondary to treatment of other malignant diseases. II. Bone marrow cytology, cytogenetics, results of HLA typing, response to antileukemic chemotherapy, and survival in a total series of 55 patients.

Secondary acute nonlymphocytic leukemia or its earlier stages, preleukemia or an acute myeloproliferative syndrome with refractory cytopenia and clonal cytogenetic abnormalities of the bone marrow, was diagnosed in 55 patients previously treated for other malignant diseases. In patients with overt leukemia, cytologic, and cytochemical studies showed predominance of the French-American-British (FAB) type M2. Cytogenetic examination demonstrated a normal karyotype in 11 cases, whereas clonal abnormalities were observed in 44 patients. Defects of chromosome 7 were observed in 24 cases, most often -7, and defects of chromosome 5 in 14 cases, most often 5q-. In addition, chromosomes 3 and 17 were possibly nonrandomly involved. Other abnormalities commonly observed in de novo acute nonlymphocytic leukemia as t(8;21) and t(15;17) were not observed and +8 rarely seen in secondary leukemia. The survival from the leukemic complication was short for the whole group of 55 patients (median, 7 months). However, a significantly longer survival was observed in a subgroup of 11 patients with a normal karyotype (P less than 0.01), due to a favorable response to antileukemic chemotherapy, and in a subgroup of 11 patients with -7 or -C as the only cytogenetic abnormality (P less than 0.01), due to a prolonged preleukemic phase, compared with the remaining 33 cases with mostly multiple karyotypic abnormalities. Three preleukemic patients with -7 who were studied during transformation to overt leukemia all developed additional cytogenetic abnormalities. According to the two-step or multistep hypothesis for malignant transformation, the prolonged preleukemic course in patients with -7 as the only abnormality could represent a premalignant stage, in which further evolution is required for development of overt leukemia. The patients showed a random distribution of blood groups and HLA types.

Evolution of oligoleukemia.

Chronic lithium administration to 22 patients with oligoleukemia did not alleviate cytopenia or stimulate bone marrow proliferative activity. The authors identified, however, pretreatment characteristics discriminating two evolutionary endpoints of oligoleukemia (marrow failure, 10 patients; overt acute leukemia, 12 patients): higher marrow leukemic infiltrate, normal myeloid precursor proportion, platelet count, and female sex all favored eventual transition to overt leukemia which, in comparison with marrow failure, was associated with a significantly longer survival duration from symptoms. For patients developing overt leukemia, survival from diagnosis was inversely correlated with the degree of marrow leukemic infiltrate. The lack of lithium responsiveness in oligoleukemia is consistent with the concept of differentiated leukemia with abnormalities either at the level of a lithium-responsive adherent cell elaborating colony stimulating activity (CSA) or at the level of CSA-responsive CFUs.