The concurrent occurrence of Leishmania chagasi infection and childhood acute leukemia in Brazil

AbstractObjectiveThis study investigated the co-existence of Leishmania chagasi infection and childhood leukemia in patients naïve to treatment; this has serious clinical and epidemiological implications.MethodsThe seroprevalence of L. chagasi antibodies prior to any treatment was investigated in children with clinical features of acute leukemia. Serological tests were performed in 470 samples drawn from under 14-year-old children from different regions of Brazil with clinical suspicion of acute leukemia. Acute leukemia subtypes were characterized by immunophenotyping using flow cytometry. Morphological analyses of bone marrow aspirates were systematically performed to visualize blast cells and/or the formation of L. chagasi amastigotes. Data analysis used a standard univariate procedure and the Pearson's chi-square test.ResultsThe plasma of 437 children (93%) displayed antibodies against L. chagasi by indirect immunofluorescence assay and enzyme-linked immunosorbent assay tests. Of the 437 patients diagnosed from 2002 to 2006, 254 had acute lymphoblastic leukemia, 92 had acute myeloid leukemia, and 91 did not have acute leukemia. The seroprevalence of L. chagasi antibodies according to the indirect immunofluorescence assay test (22.5%) was similar in children with or without acute leukemia (p-value=0.76). The co-existence of visceral leishmanasis and acute leukemia was confirmed in 24 children. The overall survival of these children was poor with a high death rate during the first year of leukemia treatment.ConclusionIn the differential diagnosis of childhood leukemia, visceral leishmanasis should be considered as a potential concurrent disease in regions where L. chagasi is endemic

Mother and child characteristics at birth and early age leukemia: a case‐cohort population‐based study

Objective: The population‐based cancer registries (PBCR) and the Information System on Live Births in Brazil (Sistema de Informações sobre Nascidos Vivos [SINASC]) have information that enables the test for risk factors associated with leukemia at an early age. The aim of this study was to identify maternal and birth characteristics associated with early‐age acute leukemia (EAL) in Brazil. Methods: A case‐cohort study was performed using secondary dataset information of PBCR and SINASC. The risk association variables were grouped into (i) characteristics of the child at birth and (ii) characteristics of maternal exposure during pregnancy. The case–control ratio was 1:4. Linkage was performed using R software; odds ratio (OR) and 95% confidence interval (CI) were calculated by logistic regression models. Results: EAL was associated with maternal occupational exposure to chemicals (agricultural, chemical, and petrochemical industry; adjOR: 2.18, 95% CI: 1.16–4.10) and with birth defects (adjOR: 3.62, 95% CI: 1.19–11.00). Conclusions: The results of this study, with the identification of EAL risk factors in population‐based case‐cohort study, strengthen the knowledge and improve databases, contributing to investigations on risk factors associated with childhood leukemia worldwide

Early childhood leukemia incidence trends in Brazil

<p>Incidence rates of childhood leukemia vary between different regions of the world. The objective of this study was to test possible trends in incidence rate of early childhood leukemia (children <5 years old at the diagnosis) in Brazil. Data from 18 population-based cancer registries (PBCRs) were analyzed (period 1999–2010). The analysis consisted of frequencies, age-adjusted incidence rates, and joinpoint regression results, including annual average percent change (AAPC) in incidence rates and 95% confidence intervals (CIs). The median age-adjusted incidence rate (AAIR) of overall early childhood leukemia was 61 per million. The AAIR for acute lymphoid leukemia (ALL) was 44 per million and nonlymphoid acute leukemia (NLAL) was 14 per million. The median ALL/NLAL ratio was 3.0, suggesting higher incidence rate of NLAL in these settings. The joinpoint analysis demonstrated increased leukemia incidence rate in João Pessoa (AAPC = 20; 95% CI: 3.5, 39.4) and Salvador (AAPC = 8.68; 95% CI: 1.0, 16.9), respectively, whereas incidence rate in São Paulo PBCR decreased (AAPC = −4.02%; 95% CI: −6.1%, −1.9%). Correlation between ALL AAIR and selected variables of socioeconomic (SES) factors was not observed. Increased AAIR regionally overtime was observed. However, the interpretation for such phenomenon should be cautious because it might reflect the access to health care, diagnosis procedures, and improvement of PBCR´s quality. The observed trend supports the necessity of further ecological studies.</p