[Clonal chromosomal aberrations in patients with aplastic anemia at the disease onset and transformation].

AIM: To estimate detectability and characteristic features of chromosomal aberrations in bone marrow cells of patients with aplastic anemia (AA). MATERIAL AND METHODS: The trial covered 155 AA patients admitted to the Hematological Research Center in 1987-2002. Cytogenetic study by G-differential staining was performed in 58 patients with AA and 5 patients with AA transforming into myelodysplastic syndrome (MDS) or acute leukemia (AL). Cytogenetic and morphological specimens of the latter's bone marrow were studied retrospectively using fluorescent in situ hybridization (FISH) with DNA probes for detection of monosomia 7 and deletion 7q. RESULTS: Clonal chromosomal aberrations were detected in 4 out of 28 patients. Further examinations revealed no aberrations. Clonal diseases developed in 7 (4.5%) of 155 patients. In 2 patients the disease transformed into paroxysmal nocturnal hemoglobinuria, 5 (3.2%) patients developed variants of MDS and AL. Monosomia 7 or deletion 7q were diagnosed in 3 cases of MDS/AL. In retrospective study of bone marrow specimens of patients with transformation in MDS/AL with monosomia 7, FISH recognized a small elevation over control values in 2 cases. CONCLUSION: Stable clonal chromosomal aberrations are not characteristic of AA. Some AA patients with subsequent MDS/AL may have minor neoplastic clone in the disease onset.

[Chromosomal aberrations in myelodysplastic syndrome].

AIM: To analyse incidence rate of chromosomal aberrations in myelodysplastic syndromes (MDS), specification of clinicomorphological features of some cytogenetic variants. MATERIAL AND METHODS: Chromosomal analysis by the method of G-differential staining of chromosomes was made in 209 patients with different variants of MDS. RESULTS; Clonal chromosomal aberrations occured in 60.8%. The following aberrations were found most frequently: deletion of the long arm of the chromosome 5 (del(5q)) - 34.6%, trisomy of chromosome 8 (14.1%), monosomy of chromosome 7 (13.4%), aberrations 3q21q26 (12.6%), aberrations of a long arm of X-chromosome (4.7%), the absence of Y-chromosome (3.1%). Complex aberrations of karyotype were found in 13.5% cases. Chromosomal aberrations determined not only clinical and morphological features but also the prognosis of the disease. CONCLUSION: Cytogenetic examination is an essential component of MDS patients examination. It allows more precise classification of MDS variant and prognostification of the disease course.

[Molecular-cytogenetic monitoring of different regimens of treatment in patients with chronic myeloid leukemia]. / Molekuliarno-tsitogeneticheskii monitoring razlichnykh rezhimov terapii u bol'nykh khronicheskim mieloleikozom.

AIM: To conduct molecular-cytogenetic monitoring of bone marrow cells in different regimens of chronic myeloid leukemia (CML) treatment. MATERIAL AND METHODS: A total of 651 samples of bone marrow from 319 CML patients were studied. 229 patients received polychemotherapy and 90 patients--interferon-alpha. Primary examination and monitoring of the treatment efficacy were performed using G-differential chromosome staining. Fluorescent in situ hybridization (FISH) was made in 75% cases. RESULTS: Interferon therapy resulted in a significant increase in the number of complete and significant cytogenetic responses. With aggravation of the disease the above responses occurred less frequently while minor and no response are encountered more often. Treatment with interferon-alpha in combination with chemotherapy is much more effective than monotherapy with interferon. CONCLUSION: G-differential chromosome staining karyotypes metaphases and detects clonal chromosome restructuring. Molecular-cytogenetic methods study chromosome restructuring at DNA level. FISH detects chimeric gene bcr/abl in cases when Ph-chromosome is not detectable by standard cytogenetic methods.

[Induced leukemias and their connection with radiation exposure]. / Indutsirovannye leikozy, ikh sviaz' s vozdeistviem radiatsii.

The cytogenetic study of bone marrow cells was performed in 40 patients with secondary leukemias which have arisen after application of cytostatic and/or radiotherapy for primary tumours (Hodgkin's disease, lymphomas, acute lymphoblastic leukemias, breast cancer and other solid tumours). The comparative analysis of results has shown, that the leukemias after irradiating or application of alkylating agents and irradiation, have the quite particular clinico-morphological and cytogenetic characteristics. In 70% of cases these diseases develops as smouldering leukemias with subsequent transformation in M-4, M-6, and rarely M-2 cytochemical variants. Primary cytogenetic events in 60% of researched karyotypes are the losses of long arms or whole chromosomes 5 and 7. In 20% of the researched cases normal karyotype was found, in the left 20%, the changes of a karyotype not including anomalies 5 and 7 chromosomes were detected. The obtained outcomes allow to consider the discharged complex of tags as reference for leukemias, induced by irradiating or chemical agents with similar mechanism of action (alkylating agents, benzene and its derivates). This complex of tags is typical for induced leukemias, and in a combination with definition of a level of stable aberrations in peripheral blood lymphocytes, can be utilised for abjection of radiation-induced leukemias from common mass of cases detected in regions, polluted by radionuclides. In this study in 60% of cases only specific for secondary leukemias chromosomal aberrations, including monosomy 5 and 7, rearrangements of 11q23 were found. On the base of the obtained data the differences in concepts of "secondary" and "induced" leukemias are considered.

Cytogenetic features of leukaemias diagnosed in residents of areas contaminated after the Chernobyl nuclear accident.

A comparison of chromosomal abnormalities in bone marrow leukaemic cells and of stable and unstable aberrations in lymphocytes of patients with hematological malignancies who live in areas with or without contamination by the Chernobyl nuclear accident has been made using FISH and G-banding. Healthy residents of these areas comprised the control group. No systematic cytogenetic differences of leukaemic cells between patients from contaminated and uncontaminated areas were observed. Lymphocyte aberrations, however, were generally higher in all subjects from contaminated areas. Comparison has been made with specific cytogenetic features of leukaemic cells and a high level of stable aberrations in lymphocytes of patients with secondary leukaemias that had developed after chemo- and/or radio-therapy.

[Immunogenetic approaches to the study of leukemia in humans]. / Immunogeneticheskie podkhody k izucheniiu leikozov cheloveka.

One hundred and ten families having one child suffering from acute leukemia were included in HLA studies. These families were found to have unequal distribution of the parent HLA-haplotypes among the sibs. Three groups of families were conditionally distinguished. The first group showed the predominance of one parental, the second group of one maternal, and the third group of one maternal and one paternal HLA haplotypes. This suggests that impairment of the evolutionally derived principle of equal participation of both gamete types of each parent in the zygote formation is deleterious for the progeny.

[Detection of isoimmune antibodies against a population of human B-lymphocytes]. / Obnaruzhenie izoimmunnykh antitel protiv populiatsii B-limfotsitov cheloveka.

Rosette-forming ability of human lymphocytes was tested before and after their sensitization with isoimmune sera against histocompatibility antigens. Anti-HLA sera inhibited the ability of T- and B- lymphocyteè to form rosettes. Some sera inhibited rosette formation mostly of B-lymphocytes; they also possessed marked capacity to react with B-lymphocytes population in prolonged lymphotoxic tests.