IgH and TCRgamma gene rearrangements, cyclin A1 and HOXA9 gene expression in biphenotypic acute leukemias.

In this study we investigated IgH and TCRgamma gene rearrangements, cyclin A1 and HOXA9 gene expression as well as the in vitro growth of biphenotypic acute leukemia (BAL) blasts in relation to acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The aim of the study was to correlate BAL morphology and its biological parameters in order to get information that might be used for additional stratification of BAL. This rare form of AL was identified in a total of 10 patients, comprising 4.3% of adult and 3.0% of pediatric patients with de novo AL referred to our institution during the 1999-2003 period. Our results indicate that IgH and TCRgamma gene rearrangements correlated well with lymphoid BAL morphology, whereas the expression of cyclin A1 correlated with myeloid and undifferentiated BAL morphology. Surprisingly, HOXA9 expression, a marker associated with myeloid cell lineage, showed no strong correlation with BAL morphology. Finally, in vitro growth of blasts during a 7-day culture showed autonomous cell growth in 3/10 AML and 3/8 myeloid BAL samples tested, but not in any of the AL with lymphoid features. Further studies are needed to confirm these findings and to extend research to a broader spectrum of cell markers.

[Sideropenic anemia in infants and toddlers]. / Sideropenicna anemija u dojenackoj dobi i dobi malog djeteta.

Iron-deficiency anemia is the most common anemia in infants. In the routine pediatric care this problem is encountered every day. Numerous factors in infancy (low birth weight, rapid growth, insufficient nutrition) are involved in the development of iron-deficiency anemia, and they must be considered when establishing diagnosis, counselling parents, and prescribing oral iron preparations. Data on 119 patients aged up to two years treated in the Division of Gastroenterology and Nutrition, Pediatric Department, University Hospital Centre Zagreb Salata between 1994 and 1999, were analyzed. We were prompted to do so because of great frequency of iron-deficiency anemia as one of associated diagnoses, and unfortunately often the only diagnosis requiring hospitalization. Out of 119 patients with iron-deficiency anemia, nine (7.7%) patients (four premature newborns and three from twin pregnancy) had to receive transfusion of erythrocyte concentrate due to very bad general condition and low red blood count, accompanied by clinical signs of anemic hypoxia. We also analyzed prenatal and perinatal history, socioeconomic living conditions of these children, i.e. their nutrition, and if they had previously received oral iron preparations. Some of the results, such as inadequate alimentation with flour, as well as insufficient prophylaxis of iron deficiency, which were found in most cases of severe anemia, point to the need of paying greater attention to this problem, better parents education, and more adequate screening for iron deficiency anemia.

Defect of NK activity in children with untreated acute lymphocytic leukemia (ALL). I. Dependence on the blast count and phenotype, and response to exogenous and endogenous alpha-interferon.

Endogenous NK-activity (eNK) against K-562 cells was determined in peripheral blood of 68 children with acute lymphocytic leukemia (ALL) before treatment. In 53% of them it was depressed, and in 47% it was within the range of control children (27) and adults (104). There was a significant negative correlation between blast contamination of peripheral blood and the level of eNK-activity. In spite of this general trend, 8 patients with high blast count have had normal eNK-activity, and 10 patients with relatively low blast count (below 50%) have had depressed eNK-activity. Examples of T ALL showed significantly lower eNK-activity than CALLA ALL. The ability of exogenous alpha-interferon (IFN) to stimulate eNK-activity was impaired in 18 of 40 examples of ALL and preserved in 22. The IFN-induced NK-response was also negatively correlated to the blast burden, but again with exceptions: Six nonresponders in spite of low blast count, and six responders in spite of high blast count in peripheral blood. IFN-inducer, poly-IC, stimulated eNK-activity only in 6 of 26 ALL samples. Surprisingly, positive correlation was found between poly-IC-induced NK-stimulation and blast count in peripheral blood. Poly-IC induced significant IFN production only in one of six cultures of ALL. Impaired eNK-activity has been attributed, in part, to "dilution" of NK cells by the blasts. Defects in production of IFN, and in response to it, may be additional reasons for depressed NK-activity in about 50% of children with untreated ALL.

Expression of haematopoietic progenitor cell-associated antigen BI-3C5/CD34 in leukemia.

The expression of progenitor cell-associated antigen CD34, defined with monoclonal antibody BI-3C5, was investigated in cells from 109 patients with leukaemia. No reactivity was found in chronic leukaemias, whereas 31% of acute myelogenous leukaemia (AML) and most non-T, non-B acute lymphoblastic leukaemia (ALL) expressed CD34. Examples of BI-3C5+ AML included M1 and M2 FAB types only; all but one were myeloperoxidase positive. In combination with pan-myeloid markers, BI-3C5 is useful for identification of immature myeloid cells.

Premature chromosome condensation in children with acute lymphocytic leukemia (L1) and malignant histiocytosis.

In this study we report the observation of premature chromosome condensation (PCC) in two children with acute lymphocytic leukemia L1 and one child with malignant histiocytosis. Cytogenetic analysis was performed on peripheral blood or bone marrow cells cultivated for 24 hours without mitogen. In all three reported cases the modal karyotype was normal, while 12.9%, 5.5%, and 5% of spreads with PCC was observed, respectively.

Defects of natural killer cell activity in children with untreated acute lymphocytic leukemia.

Natural killer (NK) activity against cells of the K-562 line was significantly depressed in 12 of 18 children (66%) with untreated acute lymphocytic leukemia (ALL). No suppression of allogeneic NK activity was observed with sera of the patients, regardless of the level of NK depression. The ability of peripheral blood lymphocytes (PBLs) to suppress allogeneic NK activity was tested in two ALL patients - one with no detectable NK activity, and one with high NK activity. No NK-suppressive activity was found with PBLs of the areactive patient; PBLs of the reactive patients exhibited some suppressive activity, but only at a particular suppressor-to-effector cell ratio. Leukemic blasts were resistant to killing by autologous NK cells stimulated by IFN, as well as to killing by allogeneic, IFN-stimulated PBLs. Leukemic blasts of an ALL patient inhibited lysis of K-562 cells in an 18-h, but not in a 4-h NK assay. The inhibition could partly be reversed by pretreatment of ALL cells with alpha interferon, suggesting that the blasts might inhibit the lysis of K-562 targets in a competitive manner. Disturbed function and/or regulation of NK cells may influence attempts at NK cell activation by lymphokines.

Subsets of childhood acute lymphoblastic leukaemia in Croatia.

As a contribution to epidemiological studies on distribution of acute lymphoblastic leukaemia (ALL) subsets in different countries, we investigated blast cell immunophenotype in 54 children with ALL from the western part of Yugoslavia. The subtype incidences were: common, 75.9%; null, 7.4%; T, 11.1%; B, 1.9%; and unclassifiable, 3.7%. This resembles the ALL pattern registered in developed countries. Hence, differences in socioeconomic status between our population and developed European countries do not result in an appreciably altered incidence of childhood leukaemia subtypes.

Cytogenetic analysis of a child with malignant histiocytosis.

This report presents the results of cytogenetic analysis of a child with malignant histiocytosis. The analysis was carried out on slides obtained following short-term cultures of peripheral blood cells. The malignant cells had a deletion of the long arm of chromosome #7, 46,XX,del(7)(q22).

Heterochromatic segment length of Y chromosome in 55 boys with malignant diseases.

By investigating heterochromatic segment variability in a group of boys with malignant disease a significantly greater value of the Yc:F index in relation to the control subjects was established.

Marker chromosome 1q+ in acute lymphocytic leukemia.

This paper presents the results of a cytogenetic analysis on a patient with acute lymphocytic leukemia (ALL) type L2 according to the FAB classification. Of the metaphases examined, 69.3% belong to the aberrant clone of pseudodiploid karyotype. Marker chromosome 14q+ has been identified in all the cells of the clone. Duplication was found in 30% of the metaphases, and in 15% triplication of the proximal segment of the long arm of chromosome #1 (q11-q21). In one metaphase the long arm of chromosome #1 is made up of segment q11-q21 four times repeated. Aberrations of chromosome #1 support the idea that heterochromatic region may be related to the higher degree of the cell malignity.