Association of loss of heterozygosity with cytogenetic abnormalities in acute myeloid leukemia and myelodysplastic syndrome

Deletions on chromosomes 5 and 7 are frequently seen in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). It is assumed that these deletions indicate loss of tumor suppressor genes on these chromosomes and until these tumor suppressor genes are identified, the functional consequences of these deletions and the molecular basis of these myeloid disorders cannot be completely understood. We evaluated loss of heterozygosity (LOH) in 44 patients (18 MDS and 26 AML, diagnosed according to WHO classification criteria) at diagnosis, using a four-microsatellite marker panel: an intragenic marker on the 7th intron of gene IRF-1 of the 5q31.1 region and three markers located inside the 7q31.1 region and correlated the LOH with karyotype abnormalities. The microsatellites chosen corresponded to chromosome regions frequently deleted in MDS/AML. The samples with Q (peak area) less than or equal to 0.50 were indicative of LOH. The percent of informative samples (i.e., heterozygous) for the intragenic microsatellite in gene IRF-1 and in loci D7S486, D7S515 and D7S522 were 66.6, 73.7, 75.5, and 48.8%, respectively. Cytogenetic abnormalities by G-banding were found in 36% (16/44) of the patients (2 of 18 MDS and 14 of 26 AML patients). We found a significantly positive association of the occurrence of LOH with abnormal karyotype (P < 0.05; chi-square test) and there were cases with LOH but the karyotype was normal (by G-banding). These data indicate that LOH in different microsatellite markers is possibly an event previous to chromosomal abnormalities in these myeloid neoplasias.

Implications of infectious diseases and the adrenal hypothesis for the etiology of childhood acute lymphoblastic leukemia

Acute leukemia is the most frequent cancer in children. Recently, a new hypothesis was proposed for the pathogenesis of childhood acute lymphoblastic leukemia (ALL). The so-called "adrenal hypothesis" emphasized the role of endogenous cortisol in the etiology of B-cell precursor ALL. The incidence peak of ALL in children between 3 to 5 years of age has been well documented and is consistent with this view. The adrenal hypothesis proposes that the risk of childhood B-cell precursor ALL is reduced when early childhood infections induce qualitative and quantitative changes in the hypothalamus-pituitary-adrenal axis. It suggests that the increased plasma cortisol levels would be sufficient to eliminate all clonal leukemic cells originating during fetal life. Because Brazil is a continental and tropical country, the exposure to infections is diversified with endemic viral and regionally non-viral infections, with some characteristics that support the recent adrenal hypothesis. Here we discuss this new hypothesis in terms of data from epidemiological studies and the possible implications of the diversity of infections occurring in Brazilian children.

Positive response to imatinib mesylate therapy for childhood chronic myeloid leukemia

Chronic myeloid leukemia (CML) is rare in the pediatric population, accounting for 2-3% of childhood leukemia cases, with an annual incidence of one case per million children. The low toxicity profile of imatinib mesylate has led to its approval as a front-line therapy in children for whom interferon treatment has failed or who have relapsed after allogeneic transplantation. We describe the positive responses of 2 children (case 1 - from a 7-year-old male since May 2005; case 2 - from a 5-year-old female since June 2006) with Philadelphia-positive chromosome CML treated with imatinib (300 mg/day, orally) for up to 28 months, as evaluated by morphological, cytogenetic, and molecular approaches. Our patients are alive, are in the chronic phase, and are in continuous morphological complete remission.

Characterization and analysis of the outcome of adults with acute myeloid leukemia treated in a Brazilian University hospital over three decades

We evaluated the outcome of 227 patients with acute myeloid leukemia during three decades (period 1 - 1980’s, N = 89; period 2 - 1990’s, N = 73; period 3 - 2000’s, N = 65) at a single institution. Major differences between the three groups included a higher median age, rates of multilineage dysplasia and co-morbidities, and a lower rate of clinical manifestations of advanced leukemia in recent years. The proportion of patients who received induction remission chemotherapy was 66, 75, and 85% for periods 1, 2, and 3, respectively (P = 0.04). The median survival was 40, 77, and 112 days, and the 5-year overall survival was 7, 13, and 22%, respectively (P = 0.01). The median disease-free survival was 266, 278, and 386 days (P = 0.049). Survival expectation for patients with acute myeloid leukemia has substantially improved during this 30-year period, due to a combination of lower tumor burden and a more efficient use of chemotherapy and supportive care.

Silencing HIF-1α reduces the adhesion and secretion functions of acute leukemia hBMSCs

Hypoxia inducible factor-1α (HIF-1α) is an important transcription factor, which plays a critical role in the formation of solid tumor and its microenviroment. The objective of the present study was to evaluate the expression and function of HIF-1α in human leukemia bone marrow stromal cells (BMSCs) and to identify the downstream targets of HIF-1α. HIF-1α expression was detected at both the RNA and protein levels using real-time PCR and immunohistochemistry, respectively. Vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α) were detected in stromal cells by enzyme-linked immunosorbent assay. HIF-1α was blocked by constructing the lentiviral RNAi vector system and infecting the BMSCs. The Jurkat cell/BMSC co-cultured system was constructed by putting the two cells into the same suitable cultured media and conditions. Cell adhesion and secretion functions of stromal cells were evaluated after transfection with the lentiviral RNAi vector of HIF-1α. Increased HIF-1α mRNA and protein was detected in the nucleus of the acute myeloblastic and acute lymphoblastic leukemia compared with normal BMSCs. The lentiviral RANi vector for HIF-1α was successfully constructed and was applied to block the expression of HIF-1α. When HIF-1α of BMSCs was blocked, the expression of VEGF and SDF-1 secreted by stromal cells were decreased. When HIF-1α was blocked, the co-cultured Jurkat cell’s adhesion and migration functions were also decreased. Taken together, these results suggest that HIF-1α acts as an important transcription factor and can significantly affect the secretion and adhesion functions of leukemia BMSCs.

A combination of STI571 and BCR-ABL1 siRNA with overexpressed p15INK4B induced enhanced proliferation inhibition and apoptosis in chronic myeloid leukemia

p15INK4B, a cyclin-dependent kinase inhibitor, has been recognized as a tumor suppressor. Loss of or methylation of the p15INK4B gene in chronic myeloid leukemia (CML) cells enhances myeloid progenitor formation from common myeloid progenitors. Therefore, we examined the effects of overexpressed p15INK4B on proliferation and apoptosis of CML cells. Overexpression of p15INK4B inhibited the growth of K562 cells by downregulation of cyclin-dependent kinase 4 (CDK4) and cyclin D1 expression. Overexpression of p15INK4B also induced apoptosis of K562 cells by upregulating Bax expression and downregulating Bcl-2 expression. Overexpression of p15INK4B together with STI571 (imatinib) or BCR-ABL1 small interfering RNA (siRNA) also enhanced growth inhibition and apoptosis induction of K562 cells. The enhanced effect was also mediated by reduction of cyclin D1 and CDK4 and regulation of Bax and Bcl-2. In conclusion, our study may provide new insights into the role of p15INK4B in CML and a potential therapeutic target for overcoming tyrosine kinase inhibitor resistance in CML.

Possible benefit of consolidation therapy with high-dose cytarabine on overall survival of adults with non-promyelocytic acute myeloid leukemia

In adults with non-promyelocytic acute myeloid leukemia (AML), high-dose cytarabine consolidation therapy has been shown to influence survival in selected patients, although the appropriate doses and schemes have not been defined. We evaluated survival after calculating the actual dose of cytarabine that patients received for consolidation therapy and divided them into 3 groups according to dose. We conducted a single-center, retrospective study involving 311 non-promyelocytic AML patients with a median age of 36 years (16-79 years) who received curative treatment between 1978 and 2007. The 131 patients who received cytarabine consolidation were assigned to study groups by their cytarabine dose protocol. Group 1 (n=69) received <1.5 g/m2 every 12 h on 3 alternate days for up to 4 cycles. The remaining patients received high-dose cytarabine (≥1.5 g/m2 every 12 h on 3 alternate days for up to 4 cycles). The actual dose received during the entire consolidation period in these patients was calculated, allowing us to divide these patients into 2 additional groups. Group 2 (n=27) received an intermediate-high-dose (<27 g/m2), and group 3 (n=35) received a very-high-dose (≥27 g/m2). Among the 311 patients receiving curative treatment, the 5-year survival rate was 20.2% (63 patients). The cytarabine consolidation dose was an independent determinant of survival in multivariate analysis; age, karyotype, induction protocol, French-American-British classification, and de novo leukemia were not. Comparisons showed that the risk of death was higher in the intermediate-high-dose group 2 (hazard ratio [HR]=4.51; 95% confidence interval [CI]: 1.81-11.21) and the low-dose group 1 (HR=4.43; 95% CI: 1.97-9.96) than in the very-high-dose group 3, with no significant difference between those two groups. Our findings indicated that very-high-dose cytarabine during consolidation in adults with non-promyelocytic AML may improve survival.

Evaluation of a father and son with atypical chronic myeloid leukemia with SETBP1 mutations and a review of the literature

We report the case of a father and son diagnosed with atypical chronic myeloid leukemia (aCML). Both patients harbored SETBP1 mutations, which are present in 24.3% of aCML patients. Moreover, both shared the variant encoding p.Pro737His, but the aCML severity was greater in the son because of the presence of two other missense mutations causing p.Asp868Asn and p.Ser885Arg alterations. SETBP1 mutations may be associated with an adverse prognosis, so their detection would help in the diagnosis of aCML and the determination of a patient's prognosis.

Chagas' Disease: an acute transfusional case report

Report of a case of acute transfusional Chagas'disease in a four-year-old child with a previous diagnosis of acute lymphocytic leukemia, transmitted in São Paulo, the Capital of São Paulo State, Brazil. Epidemiological investigation disclosed the donor's serological positivity and his previous residence in an area where Chagas' disease is endemic. The importance of adequate sorological screening in blood donors is evident. It should be stressed that this is the first case notified to the Superintendência de Controle de Endemias (SUCEN) (Superintendency for the Endemy Control) of the State Secretariat of Health, São Paulo, for the last five years.

Antibody to human T-lymphotropic virus in a patient with Guillain-Barré syndrome (case report)

Serum sample obtained from a male, 12 year old patient suffering from Guillain-Barré syndrome (GBS) was positive for human T-lymphotropic virus (HTLV-I) antibody by the enzyme-linked immunosorbent assay (ELISA) and the Western Blot analysis (WB). Attempts to isolate enteroviruses (including poliovirus) from faecal material in both tissue culture and suckling mice were unsuccessful; in addition, acute and convalescent paired serum samples did not show any evidence of recent poliovirus infection when tested against the three serotypes. Specific tests for detection of Epstein-Barr virus infection were not performed; however, the Paul-Bunnel test yielded negative results. ELISA for detection of anti-cytomegalovirus IgM was also negative. The concomitant occurrence of either adult T cell leukemia (ATL) or lymphoma was not recorded in this case.

CRYPTOSPORIDIOSIS IN PEDIATRIC PATIENTS

Cryptosporidium was detected in 21 (3.8%) individual stool samples collected from 553 pediatric patients hospitalized in our center employing a Telemann concentration technique (formalinethercentrifugation) and stained with the modified Kinyoun method. The mean age of populations with Cryptosporidiosis (16 boys and 5 girls) was 11 months; 15 months for girls and 6.5 for boys. Ages of 81% of them were less than 19 months. Seventysix per cent of patients lived on the outskirts of Buenos Aires and 71% lacked pretreated running water at home. In 62% of the cases parasitological diagnoses coincided with warm seasons. At diagnosis mucous (63%) or watery (36%) diarrhea was presented in 90% of the patients with a median of 5 (38) bowel movements per day. Fever was presented in 66% of patients while abdominal pain and vomits in 60% and 52%, respectively. The median time from hospitalization up to parasitologic diagnosis was 20 days. Concomitant diseases observed were malnutrition, acute leukemia, bronchiolitis, HIV infection, anemia, celiac disease, myelofibrosis, vitelline sac tumor, neutropenia, osteosarcoma and dehydration. Cryptosporidiosis in our environment seems to occur more frequently in children younger than 18 months of age; who present diarrhea; are immunodeficient; come from a low socioeconomical background; and who live in poor sanitary conditions with no potable running water.

VERTICAL TRANSMISSION OF HTLV-I/II: A review

The vertical transmission of the human T-cell lymphotropic virus type I (HTLV-I) occurs predominantly through breast-feeding. Since some bottle-fed children born to carrier mothers still remain seropositive with a frequency that varies from 3.3% to 12.8%, an alternative pathway of vertical transmission must be considered. The prevalence rate of vertical transmission observed in Japan varied from 15% to 25% in different surveys. In Brazil there is no evaluation of this form of transmission until now. However, it is known that in Salvador, Bahia, 0.7% to 0.88% of pregnant women of low socio-economic class are HTLV-I carriers. Furthermore the occurrence of many cases of adult T-cell leukemia/lymphoma and of four cases of infective dermatitis in Salvador, diseases directly linked to the vertical transmission of HTLV-I, indicates the importance of this route of infection among us. Through prenatal screening for HTLV-I and the refraining from breast-feeding a reduction of ~ 80% of vertical transmission has been observed in Japan. We suggest that in Brazil serologic screening for HTLV-I infection must be done for selected groups in the prenatal care: pregnant women from endemic areas, Japanese immigrants or Japanese descendents, intravenous drug users (IDU) or women whose partners are IDU, human immunodeficiency virus carriers, pregnant women with promiscuous sexual behavior and pregnant women that have received blood transfusions in areas where blood donors screening is not performed. There are in the literature few reports demonstrating the vertical transmission of HTLV-II.

Sanitary conditions of a colony of urban feral cats (Felis catus Linnaeus, 1758) in a zoological garden of Rio de Janeiro, Brazil

The colony of urban stray cats living in the Rio de Janeiro zoological garden was studied in order to develop a population and health control program. As many cats as possible were captured during two months (47 animals) and were classified according to gender, age, weight and coat markings. They were submitted to a general health evaluation, examined for the presence of ectoparasites and sent to a surgical neutering program. All animals had a blood sample drawn for CBC, platelet count, heartworm and retroviruses detection. Capillary blood smears were made for hemoparasites detection. Coat marking and colors were tabby (59.7%), followed by solid black (17%); torbie (10.6%); bicolor (10.6%) and harlequin (2.1%). The only ectoparasites found were fleas, which infested 28% of the animals. The hemoparasites found were Haemobartonella felis (38%) and piroplasmas that could not be differentiated between Cytauxzoon spp. and Babesia spp. (47%). No cat was found infected by Dirofilaria immitis or FeLV (Feline Leukemia Virus), although FIV (Feline Immunodeficiency Virus) antibodies could be detected (21%). There was no correlation between hemoparasites and FIV infections. The estimated total cat population (mark-recapture method) was 59; 68% female and 32% male, suggesting that a neutering program is in fact needed.

INCIDENCE OF DIARRHEA BY Clostridium difficile IN HEMATOLOGIC PATIENTS AND HEMATOPOIETIC STEM CELL TRANSPLANTATION PATIENTS: RISK FACTORS FOR SEVERE FORMS AND DEATH

We describe the rate of incidence of Clostridium difficile-associated diarrhea (CDAD) in hematologic and patients undergone stem cell transplant (HSCT) at HC-FMUSP, from January 2007 to June 2011, using two denominators 1,000 patient and 1,000 days of neutropenia and the risk factors associated with the severe form of the disease and death. The ELISA method (Ridascreen-Biopharm, Germany) for the detections of toxins A/B was used to identify C. difficile. A multivariate analysis was performed to evaluate potential factors associated with severe CDAD and death within 14 days after the diagnosis of CDAD, using multiple logistic regression. Sixty-six episodes were identified in 64 patients among 439 patients with diarrhea during the study period. CDA rate of incidence varied from 0.78 to 5.45 per 1,000 days of neutropenia and from 0.65 to 5.45 per 1,000 patient-days. The most common underlying disease was acute myeloid leukemia 30/64 (44%), 32/64 (46%) patients were neutropenic, 31/64 (45%) undergone allogeneic HSCT, 61/64 (88%) had previously used antibiotics and 9/64 (13%) have severe CDAD. Most of the patients (89%) received treatment with oral metronidazole and 19/64 (26%) died. The independent risk factors associated with death were the severe form of CDAD, and use of linezolid.