The diagnosis of preleukaemia

Smoldering acute myelogenous leukemia in the elderly

Out of 75 consecutive elderly AML patients who did not receive anti-leukemic treatment (52 pts) or failed to respond to differentiating agent (23 pts), 6 patients had survivals of 13.2 to 98 months with treatment restricted to supportive care. This cut-point is far longer than the median survival of the 235 elderly patients (3.5 mo.), either untreated (med. survival: 1 mo.) or treated (with treatment ranging from conventional induction to palliative chemotherapy) (4 mo.), admitted to our department within the same period of time. These cases of smoldering AML (4 women, 2 men) were all of AML2 FAB subtype (4 de novo, 2 post MDS) and presented with a significantly better performance status, lower WBC and circulating blast counts, higher platelet counts and with lower bone marrow infiltration than AML cases with more rapid progression. Cytogenetical analysis when available (3 pts) showed normal karyotypes and clonogenic assay performed in 3 of these patients showed a lack of (2 pts) or reduced in vitro leukemic cell growth (1 pt). The identification of specific characteristics of smoldering leukemia in the elderly might be an important development in the understanding of the physiopathology of acute leukemia and a tool for helping decision-making when selecting the time and intensity of cytotoxic treatment in these older patients.

The contribution of Auer rods to the classification and prognosis of myelodysplastic syndromes

Auer rods were first recognized at the beginning of this century. Their presence soon became considered to be an unequivocal manifestation of a leukemic process. Possibly influenced by this long-held assumption, in 1982 the French-American-British co-operative group (FAB) incorporated the presence of Auer rods into a classification system of the myelodysplastic syndromes that remains in widespread clinical usage today. Although unsubstantiated at the time, the presence of Auer rods was suggested to indicate a rapidly progressive disorder and a poor prognosis. In the absence of studies confirming the utility of Auer rods as a diagnostic criterion, the FAB classification system of myelodysplastic syndromes has been widely used to allocate therapy. In this review we examine the early descriptions of Auer rods and critically evaluate the studies examining the value their presence has in the classification and prognosis of patients with myelodysplastic syndromes.

Clinical, biochemical and cytokinetic parameters for distinguishing smouldering and rapidly proliferating variants of acute leukaemia

In a retrospective study, 10 patients with smouldering leukaemia (SML) were examined between 1982 and 1987. These patients typically showed the morphological criteria of acute myelogenous leukaemia (greater than 30% blasts in the bone marrow) in most cases together with a long survival time (median 16 months; 5 patients more than 22 months; 5 patients between 2.3 and 6.3 months) without the use of aggressive chemotherapy. At initial diagnosis the blast cell populations of patients with SML were characterized by significantly reduced cytosolic thymidine kinase activity (TK), thymidine-incorporation (dTR) and deoxyuridine incorporation (dUR) into DNA as well as reduced amounts of DNA-synthesizing S-phase-cells (%S) in the bone marrow (BM), compared to those patients with a rapidly proliferating acute myelogenous leukaemia (AML) and to healthy individuals. None of the SML-patients showed clinical symptoms such as night-sweat, weight-loss, hepato- and splenomegaly or lymphadenopathy at initial diagnosis. For characterization of SML vs AML we recommend the use of the biochemical parameter TK activity and the observed absence of the above-mentioned clinical symptoms. The transition to the rapidly proliferating type of AML can be recognized by an increase in the values of the biochemical and cytokinetic parameters. The blast count in the bone marrow is not suitable as a diagnostic criterion for the definition of SML vs AML or its transition to the rapidly proliferating type of AML.

Myelodysplastic syndromes

A cure for MDS has yet to be found. The aim of therapy is to attempt to restore normal hematopoiesis and prevent evolution to acute leukemia. The major trend is supportive care. Blood counts and bone marrow aspirations are taken to evaluate the disease, and transfusions of blood products and antibiotics are given when necessary. A new encouraging modality of therapy is the use of hematopoietic growth factors to reverse cytopenias. As there is no curative treatment for MDS, the patient is likely to be offered investigational drugs either singly or in combination. Future trends in the treatment of MDS will be combinations of agents including biological agents with retinoic acid or vitamin D, low-dose Ara-C, the interferons, and colony-stimulating factors.

The effect of cytosine arabinoside on CFU-GM from patients with myelodysplastic syndrome

CFU-GM clonal growth was examined in bone marrow from patients with myelodysplastic syndrome (MDS) in the presence of Ara-C at 10(-8) M and 4 X 10(-8) M and the response compared to the effect on progenitors from normal subjects. Seventy-three percent of marrow cultures from patients with MDS showed colony growth below the 95% confidence limits for normal subjects in the presence of 10(-8) M Ara-C. At 4 X 10(-8) M Ara-C 43% of marrow cultures had subnormal colony growth. These results suggest that CFU-GM from patients with MDS may have a greater than normal sensitivity to Ara-C.

Utility of the FAB classification for myelodysplastic syndromes: investigation of prognostic factors in 237 cases

The utility and prognostic significance of the FAB classification was studied in 237 patients with a myelodysplastic syndrome. No significant differences in actuarial survival and probability of transformation to acute leukaemia were found in patients with RA, AISA or CMML. The median survival time for the RA group was 50 months, for the AISA and CMML subclasses more than 60 months. The probability of transformation for the RA, AISA and CMML subgroups showed a linear trend with a probability of 25% for the RA, 16% for the AISA and of 18% for the CMML groups after a 5 year observation period. A uniformly poor prognosis was found for the RAEB and RAEB/t subgroups with median survival times of respectively 9 and 6 months. Chromosomal abnormalities were found in 68 out of 155 patients (44%). Patients with only normal metaphases or with abnormal metaphases together with karyotypic normal cells had a longer median survival time and a lower probability for transformation as compared to those with only abnormal metaphases. The most important factor in prognosis is the number of blast cells in blood and bone marrow. Age and sex, and certain quantitative and qualitative abnormalities in the peripheral blood appear of limited prognostic value for patients with RA, AISA and CMML. The longer life expectancy of 35 patients with CMML as compared to other series seems to be related to the percentage of blast cells at the time of diagnosis.

Balloon-like platelets in myelodysplastic syndromes--a feature of dysmegakaryopoiesis?

Large bizarre platelets are a frequent finding in the peripheral blood of the myelodysplastic syndrome (MDS). In this study we describe a distinct subpopulation of platelets in MDS which by phase contrast microscopic examination seems to have a balloon-shaped bulge of the cell membrane. Increased numbers of these atypical platelets were found in 24 of 27 MDS patients (89%). Only 3 patients, all with ringsideroblastic anemia, had normal platelet morphology. The number of atypical platelets were negatively correlated (r = 0.44; p = 0.021) to the peripheral platelet counts in MDS. Among 48 patients with acute leukemia, chronic lymphoproliferative or chronic myeloproliferative disorders, 13 (27%) had atypical platelets. Here, but not in the MDS group, atypical platelets seemed to be associated with recent chemotherapy. In a group of patients with benign hematological disorders abnormal platelet morphology was seen only occasionally. The described atypical platelets most likely reflect maturation disturbances of the megakaryopoiesis. An increased value (greater than 1%) in a cytopenic patient would suggest a diagnosis of MDS, unless associated with recent cytotoxic therapy.

The role of aggressive chemotherapy in the treatment of the myelodysplastic syndromes

Fifteen patients with the initial diagnosis of myelodysplastic syndrome (MDS) received aggressive chemotherapy with high dose cytarabine or with a standard acute myeloid leukaemia (AML) regime. Cases treated with aggressive chemotherapy were either younger individuals with refractory anaemia with excess of blasts (RAEB) or patients, irrespective of age in advanced stages of MDS (RAEB in transformation or after evolution to frank AML), who did not have a major infection at the time of presentation. Age seemed to be the most important factor in determining the outcome of aggressive remission induction chemotherapy in MDS: 86% of the patients less than 50 years entered complete remission, compared to only 25% in the older age group. In spite of intensive consolidation therapy the duration of complete remission was short. We conclude that young patients (less than 50 years) with excess of bone marrow blasts should be treated with aggressive chemotherapy even in the early stages of the disease. Elderly patients in advanced stages of MDS should be treated with less aggressive chemotherapy.

Nuclear bridging of erythroblasts in acquired dyserythropoiesis: an early and transient preleukemic marker

The clinical, hematologic, and histological characteristics of two patients who progressed from refractory anemia to acute leukemia are described. When first studied, nuclear bridging of erythroblasts, similar to that seen in congenital dyserythropoietic anemia type I and megakaryocytic dysplasia, were the only abnormalities. Within 6 years, both patients died, the first of acute nonlymphocytic leukemia, the second of erythroleukemia. Nuclear bridging of erythroblasts in the marrow of these patients was an early and transient phenomenon and was not observed during the terminal phase of leukemia.

Prognostic factors for survival of 194 patients with low infiltrate leukemia

Prognostic factors were identified from the histories of 194 patients diagnosed as having low infiltrate leukemia (LIL) between 1973 and 1981, when the policy was to delay treatment until there was evidence of progressive disease or life-threatening morbidity. Their median age was 59 yr; 63% were male; 30 had had a malignant disease previously. Presenting symptoms included anemia, 82%; infections, 15%; and hemorrhage, 16%. The group's median survival was 42 weeks, with high marrow cellularity and percentage of blasts, impairment of bone marrow, liver or renal function, age over 65 yr and performance status less than 80% associated with poorer survival. Cytogenetic changes associated with poor survival included loss of chromosome 5 or 7, additional chromosome 8, karyotypic instability, and presence of 100% abnormal metaphases. A regression model including terms for blood and bone marrow features, and age at hospital admission was able to stratify patients into prognostic groups in the same population and in an independent population admitted prior to 1973. Further prospective testing of the model is required. Twenty-six of the 78 patients who were eventually treated with combination chemotherapy achieved complete remission. The presence of Auer rods, diagnosis of acute leukemia or refractory anemia with excess blasts, rapid increase in marrow infiltrate and favorable cytogenetic karyotype were associated with response. Delaying treatment in all patients was found to have improved only modestly the survival of patients with LIL.

Acute biphenotypic leukaemia (myeloid and null-ALL type) supervening in a myelodysplastic syndrome

An acute leukaemia was seen in a 72-year-old patient with a myelodysplastic syndrome (MDS) of 14 months duration, who had been treated only with steroids. The morphological appearance of the blast cells suggested a poorly differentiated cell type. Surface marker analysis, including double staining studies, showed the coexistence of a population of null acute lymphoblastic leukaemia (ALL) blast cells together with acute myeloid leukaemia type cells. No chromosomal alterations were detected. The change from a chronic MDS to an acute leukaemia of mixed (myeloid and null ALL) type suggests either transformation of a pre-existing abnormal clone or de novo appearance of two separate leukaemic clones.

The effect of retinoids on CFU-GM from normal subjects and patients with myelodysplastic syndrome

Five retinoid analogues differ in their effects on the growth of CFU-GM from normal human marrow. At concentrations above 10(-6) M all have inhibitory activity. This is maximal with 13-cis-retinoic acid. At lower concentrations the effect of retinoids is usually to reduce clone size rather than clone numbers though 10(-8)-10(-7) M etretinate increases clone size. The incubation of marrow cultures in the presence of 10(-6) M all-trans retinoic acid showed that in normal subjects colony counts are never reduced to less than 45% of the control value and total clone counts to less than 70% of the control value. In cultures from patients with myelodysplastic syndrome 20 out of 34 cases showed a greater inhibition of colony numbers than normal and 14 out of 35 cases showed a greater reduction in total clone numbers than normal. The results suggest that CFU-GM from some patients with myelodysplastic syndrome may have a greater sensitivity than normal to the inhibitory effect of retinoic acid.