Hemoglobin content of individual erythroblasts in hematopoietic dysplasia: marked heterogeneity at late stages of maturation.

Defective hemoglobin synthesis and gross morphologic abnormalities of erythroblasts are striking features of hematopoietic dysplasia. In order to define the effects of defective hemoglobin synthesis on hemoglobin content of erythroblasts at each stage of maturation, we measured the hemoglobin content and concentration of individual erythroblasts at various stages of maturation in the bone marrow by scanning microspectrophotometry. In contrast to normal erythroblasts, those from hematopoietic dysplasia had decreased hemoglobin content and decreased hemoglobin concentration at late stages of maturation. This observation, together with the observed near-normal hemoglobin content and concentration of circulating red cells in this disorder, suggests that polychromatophilic erythroblasts with decreased hemoglobin content fail to complete normal maturation. The abnormalities in hemoglobin content observed in vivo in hematopoietic dysplasia could be reproduced in the in vitro cultures of erythroid progenitors of bone marrow cells from the patients.

Acute lymphoblastic leukemia with trisomy 21 constitutional mosaicism.

Acute lymphoblastic leukemia was diagnosed in an 11-year-old girl with mild signs of Down's syndrome. She was known since birth to have a constitutional mosaicism (46,XX/47,XX,+21c). At initial diagnosis of acute leukemia, additional chromosome changes were found in bone marrow blasts: hyperdiploidy > 50, with a structural abnormality. She was treated with a standard chemotherapeutic protocol, and has remained in complete remission for more than 3 years. The constitutional mosaicism evolved toward normalization year after year in the blood and under the effect of chemotherapy in the bone marrow.

Myelodysplastic syndromes in childhood: is the FAB classification relevant? Report of 81 children from a French multicentre study. French Group of Cellular Hematology.

We reviewed the peripheral blood and bone marrow smears of 81 children with myelodysplastic syndrome (MDS). The morphological FAB classification was applicable in 59 children (72.8%): RAEB and RAEBt were the most frequent, 32 cases (39.5%). CMML was observed in 15 cases (18.5%) and in 25% of them, serological evidence for a recent EBV infection was demonstrated. In 22 cases (27.2%), the FAB classification was not convenient. In some of these children, dysmyelopoiesis was associated with constitutional disorders. Among these various inherited conditions, Down syndrome in which myelodysplasia is the expression of an abnormal clonal hematopoiesis, and mitochondrial cytopathies in which MDS is the hematological expression of a polyclonal multi-organ disease. The FAB classification does not appear to be satisfactory for all the disorders included in the group of childhood MDS and should be modified for specific use in children.

[Macrophage activation syndrome in primary human herpes virus-6 infection: a rare condition after liver transplantation in infants]. / Syndrome d'activation macrophagique au cours de la primo-infection pat le 6e virus herpétique humain: une affection certainement méconnue au cours de la transplantation hépatique chez l'enfant.

Human herpes virus-6 primary infection generally occurs during the first three years of childhood and is generally asymptomatic. The virus has been identified as the causal agent of exanthemum subitum in children or mononucleosis-like disease in adults, and may also cause several disorders in immunocompromised patients. We report a clinical case of acute rejection observed 29 days after orthotopic liver transplantation in a 22-month-old child associated with acute hepatitis and a hemophagocytic syndrome on day 38. Human herpes virus-6 primary infection was identified based on several virological tests: seroconversion, detection of viral DNA in bone marrow and peripheral blood after polymerase chain reaction, and detection of viral replication in peripheral blood. Tests for Epstein-Barr virus, cytomegalovirus or Parvovirus B19 infections were negative. After treatment by ganciclovir (Cymévan(R)), clinical status improved.

[Hereditary spherocytosis. Course and value of subtotal splenectomy]. / Sphérocytose héréditaire. Evolution et intérêt de la splénectomie subtotale.

BACKGROUND: Effectiveness of subtotal splenectomy, a procedure recently advocated as an alternative treatment to total splenectomy for patients with hereditary spherocytosis (HS), has been evaluated. METHODS AND PATIENTS: Eighty-eight patients (74 children) with HS were included in this series. Clinical presentations ranged from asymptomatic cases to severe transfusion-dependent forms. Stunting of growth occurred in four cases; chronic fatigue was observed in 30 cases and cholelithiasis in 21 cases. Among the red cell indices measured by laser light scattering on Technicon H2, the most reliable for diagnosis was the abnormal percentage of hyperdense red cells (98% of HS patients). Osmotic gradient ektacytometry, used to measure membrane deformability and impairment of maximal deformability due to a reduction of erythrocyte surface, always showed the characteristic curves of HS. RESULTS: Subtotal splenectomy was performed in 24 patients leading to a remnant spleen of about 25% of normal for age volume. This decreased the hemolytic rate while adequately sustaining the phagocytic function of the spleen (assessed by percentage of "pitted erythrocytes" and technetium 99n scans of the remnant). However, the observed reduction in hemolytic rate was not as extensive as that observed after total splenectomy (six cases) and subtotal splenectomy did not entirely prevent risk of cholethiasis (three cases). CONCLUSION: This subtotal splenectomy (+/-cholecystectomy) has to be particularly considered for children with transfusion-dependent forms of HS, in order to obtain the benefits of increased hemoglobin levels without the pending risk throughout life of overwhelming post-splenectomy infections.

[Myelodysplastic syndromes in children, Groupe d'étude des myélodysplasies de l'enfant de la Société d'hématologie et d'immunologie pédiatrique (SHIP)]. / Syndromes myélodysplasiques de l'enfant. Groupe d'étude des myélodysplasies de l'enfant de la Société d'hématologie et d'immunologie pédiatrique (SHIP).

Myelodysplastic syndromes (MDS) in children constitute a heterogeneous disorder, including 'primary' MDS and MDS associated with constitutional abnormalities. The Franco-American-British (FAB) cytological classification for adults can be applied for childhood in 50 to 100% of the cases. The transformation into acute myeloblastic leukemia often occurs, but stabilisation or spontaneous regression of the disease may also be observed. The therapeutic decision is difficult because there is no predictive factor of the course of the disease. Allogenic bone marrow transplantation is the best curative option when treatment is necessary.

[Myelodysplastic syndromes in children]. / Les syndromes myélodysplasiques de l'enfant.

Myelodysplastic syndromes are clonal haemopathies known to exist in elderly people where they are classified into 5 categories: refractory anaemia, acquired idiopathic sideroblastic anaemia, refractory anaemia with excess of blasts, refractory anaemia with excess of blasts undergoing acute transformation, and chronic myelomonocytic leukaemia. Transformation into acute leukaemia is frequent. These syndromes seem to be rarer in children, but they are often misdiagnosed. Some of their forms are particular to childhood. They include association with constitutional blood diseases predisposing to acute leukaemia, or with congenital or non-congenital malformative syndromes; there are hypoplastic forms, forms evolving towards stabilization of haematological abnormalities, and border forms with certain myeloproliferative syndromes. The diagnosis of myelodysplasia rests on morphological, functional, biochemical, isotopic data reflecting inefficient haematopoiesis, and on cytogenetic data. Studies of clonality and malignancy markers will in the near future enable us to distinguish between true preleukaemic states and polyclonal constitutional or virus-induced myelodysplasias, probably more frequent in children. The choice of treatment depends on the severity of the myelodysplastic syndrome, defined by the initial partial blastosis, the presence of cytogenetic anomaly and the certainty of clonality. In cases with poor prognosis, early bone marrow allograft is the only possible treatment.

Characterization of circulating erythroid progenitor cells in human newborn blood.

The pattern of in vitro growth of erythroid progenitors in cord blood was assayed by the methyl cellulose culture system. The erythroid nature of colonies in culture was determined by Soret band examination for hemoglobin and by immunofluorescence for specific membrane protein spectrin, as well as by conventional techniques. In contrast to adult blood cultures, we found small but definite erythroid colony growth in the cultures of cord blood progenitors in the absence of added Ep (endogenous erythroid colonies). In addition, in the presence of Ep increased numbers of progenitors were found in cord blood compared with adult blood. Comparison of cultures from newborns, normal adults, anemic adults, and adults with PV and myelofibrosis showed that endogenous erythroid colonies are also found in cultures of patients with PV and myelofibrosis but not in cultures of normal cells and cells from anemic subjects. The physiologic relevance of these endogenous colony-forming cells in newborn blood is unknown; however, we speculate that they may be related to residual extramedullary erythropoiesis at birth.

Inactivated X chromosome fold in human leukemia and related clonal disorders.

A disturbance of the X chromosome inactivation process has been demonstrated in some human tumors. In order to study this phenomenon in leukemia, the site of unusually frequent folding in Xq13-q21 was used as a morphological marker. A total of 858 GTG-banded mitoses from 61 women with different hematological malignancies were analyzed, 35 of them with normal karyotype and 26 with chromosome aberrations. The folding patterns and the fold percentage remained unchanged in our patients. Using this marker, X-inactivation could easily be verified in leukemia and related disorders on routine preparations.

Enrichment of murine granulomonocytic progenitors using a continuous linear Ficoll-Isopaque gradient.

Murine bone marrow was fractionated using a Ficoll-Isopaque continuous linear gradient characterized by an osmolarity of 290 mOsm constant throughout the gradient and a physiological pH of 7.4. The cellular peak detected prior to fractionation by means of a 405 nm light beam served as a guide for determining fraction collection. Under these conditions CFC enrichment was observed constantly for densities lower than that of the cellular peak. In 17 experiments the enrichment factor amounted to 3.6 +/- 1.4. Enrichment appeared to be due to both an increase in CFC concentration and an improvement in CFC cloning efficiency. A correlation between the concentration of CFC and that of undifferentiated blasts was observed. The CFC density distribution was dependent on the cell load. For cell loads lower than 25 x 10(6) the modal density of CFC was within the range 1.0615-1.0715. For cell loads higher than 25 x 10(6) there was a shift of the distribution curve towards higher density. Clu-CFC appeared to be denser than CFC. This increase in density may be due to a maturation process from CFC to Clu-FC as a maturation gradient with increasing density was found for the granulocytic series and for erythroblasts.

Acute myeloblastic leukemia after immunodepressive therapy for primary nonmalignant disease.

Three patients treated with immunodepressive chemotherapy over a period of 43, 60, 38 months respectively, for primary nonmalignant disease, developed AML after cessation of chemotherapy. During the months preceding the AML outbreak, there were hematologic changes with seemed to reveal a preleukemic state. Our 3 patients, and 8 previously published cases, making a total of 11 patients, developed AML after chemical immunodepression for reasons which were neither hematologic nor neoplastic.

[Myelodysplasia in children and mitochondrial cytopathies]. / Myélodysplasies de l'enfant et cytopathies mitochondriales.

Sideroblastic anemia associated with vacuolization of haemopoietic precursors can be observed in some constitutional diseases associated with mitochondrial DNA deletion. In this condition, it is the haematological expression of a multi-tissue disorder. Haemopoiesis is polyclonal, without abnormality of nuclear DNA differing from the acquired idiopathic sideroblastic anemias which arise from a clonal transformed stem cell. This model of childhood polyclonal myelodysplasia can be observed in others myelodysplasias associated with constitutional polymalformative syndromes.

[Granulocyte progenitor cells (CFC) culture in the adult chronic idiopathic neutropenia. A study of 12 cases (author's transl)]. / Cultures des progéniteurs granulocytaires (C.F.C.) au cours des neutropénies chroniques apparemment primitives. A propos de 12 cas chez l'adulte.

Granulocyte progenitors (CFC) from 12 patients with idiopathic neutropenia were cultured in vitro and followed, in some cases, for several months. The results were similar whatever the degree of neutropenia and in the presence or absence of medullary hypoplasia. The medullary concentration of CFC was always clearly depressed, which correlated with a very low total number of CFC. In every case, when the cloning efficiency was low, there were few CFC per 10(5) metamyelocytes plated, which suggests an increase in mitotic amplification between the progenitor and the mature granulocytes. When circulating CFC were cultured, there was little or no growth, confirming the paucity of CFC in the host. No patient had an increase in cloning efficiency in marrow or blood that might have suggested ineffective granulopoiesis. In four patients, stimulatory or inhibitory activity in serum was studied; one serum was stimulatory, another, on two occasions, inhibitory. Possible machanisms for these results and their prognostic value are discussed.

Acute megakaryocytic leukemia (AMKL) with major myelofibrosis in an infant. Diagnosis by liver biopsy and response to treatment.

An infant presented with enlarged liver and spleen and profound pancytopenia. Severe marrow fibrosis impeded the diagnosis which was achieved by liver biopsy: Fibrosis surrounded foci of blasts which were shown by immunologic markers to originate from the megakaryocytic lineage. Complete sustained remission was obtained by low-dose aracytine therapy. The child was disease-free at 40 months' follow up.

[Erythroblastopenia in a child during treatment of a neuroblastoma]. / Erythroblastopénie de l'enfant au cours du traitement d'un neuroblastome.

A 4 year-old child being treated for neuroblastoma developed erythroblastopenia. We used specific erythroid lineage markers (hemoglobin and spectrin) and in vitro erythroid colony assays to characterize this hematologic picture and discuss its relationships with the disease and its treatment.

The GEN.S: a fortuitous finding of a routine screening test for hereditary spherocytosis.

As part of the evaluation of the GEN.S (Coulter), we compared the Mean Corpuscular Volume (MCV) to the Mean Spherized Corpuscular Volume (MSCV) assessed during the reticulocyte count procedure under hypo-osmotic conditions. A sub-group of patients with hereditary spherocytosis (HS) was singled out: in all of them, the MSCV became smaller than the MCV. As the cell volume normally increases in red cells derived from other patients in the same conditions, we decided to further study the reason for this particular behaviour of HS red cells. Whereas normal red cells are able to undergo an osmotic expansion, the spherocytes reach a critical osmotic volume leading to cell fragmentation consistent with the decrease of MSCV. This fortuitous finding is likely to be a reliable improvement for the routine screening of HS.

Myelodysplasia in childhood may be a polyclonal disease.

Myelodysplasia in childhood can be associated with constitutional abnormalities. Two main situations can be observed: constitutional diseases such as Down's Syndrome may be the first step of a malignant stem cell transformation leading to monoclonal hematopoiesis. However, in other situations such as mitochondrial cytopathies or other polymalformative syndromes, myelodysplasia may simply be the hematological expression of a multi-tissue constitutional disease. In such cases, the bone marrow karyotype is usually found to be normal and, in affected females, clonality studies show a polyclonal pattern. Clonality assessment should be, when possible, a mandatory step before any major therapeutic decision during the course of childhood myelodysplasia.

Abnormal chromatin clumping in granulocytes in a case of Ph1-negative, BCR-ABL rearrangement positive, haematologically atypical chronic myeloid leukaemia (CML).

In the present study, we report the case of a patient displaying an abnormal chromatin clumping (ACC) syndrome, a rare disease which shares features with both myeloproliferative and myelodysplastic disorders. Although various non specific cytogenetic abnormalities have been observed in ACC, the presence of a Ph1 chromosome has not been reported. In our patient, despite a lack of Ph1, PCR analysis of blood and bone marrow samples revealed a BCR-ABL rearrangement. These results indicate that at least some cases of ACC syndrome could represent a form of Ph1-negative chronic myeloid leukaemia.

Low-dose arabinosyl cytosine therapy of AML may be effective after failure of high or conventional doses.

In 3 patients with ANLL, chemotherapy including high or conventional doses of Ara-C had been ineffective. However subsequent treatment with low-dose (LD) Ara-C induced a PR or CR which were sustained with regular LD Ara-C reinduction courses. Survival of the 2 patients with PR was 24 and 8 months respectively. The patient with CR was alive 18 months after a bone marrow graft. In 2/3 cases, the cytogenetic abnormalities initially detected disappeared with treatment. These observations suggest that the cellular mechanism of action of LD Ara-C is different from that of HD Ara-C, but do not favour a differentiating action of LD Ara-C. LD Ara-C can be prescribed as a salvage therapy even after failure of high or conventional doses.