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1.
Front Microbiol ; 15: 1420226, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39139374

RESUMO

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, is an important public health problem, occurring mainly in Latin America. The disease has a major social and economical effect, negatively impacting the life of the infected individuals, and bringing great costs to public health. An early and accurate diagnosis is essential for administration of early treatment. In addition, prognostic tests may aid disease management, decreasing hospitalization costs. However, the serological diagnostic scenario for CD still faces several challenges, making the development of new diagnostic kits a pressing matter. Facing this scenario, several researchers have expanded efforts in developing and testing new antigens, such as recombinant proteins and recombinant multiepitope proteins, with promising results. These recombinant antigens offer several advantages, such as improved sensitivity and specificity, in addition to facilitated scaling. Also, it has been possible to observe a rising number of studies using ELISA and point-of-care platforms, employing these antigens in the past few years. Among them, recombinant proteins were the most applied antigens, demonstrating great capacity to discriminate between positive and negative samples. Although fewer in number, recombinant multiepitope proteins also demonstrated an improved diagnostic performance. Indeed, a great number of studies employing these antigens showed sensitivity and specificity values above 90%, greatly impacting diagnostic accuracy. Nevertheless, despite the good results found, it is still possible to observe some bottlenecks in the development of new antigens, such as the scarcity of tests with sera from the acute phase and the variability of results in different geographic areas. In this sense, aiming to contribute to control and health programs, the continuous search for a more accurate serological diagnosis is essential, both for the acute and chronic phases of the disease.

2.
J Clin Sleep Med ; 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38958060

RESUMO

STUDY OBJECTIVES: Sleep disturbances are common in neurodevelopmental disorders (NDDs), affecting patients and caregivers' quality of life. SYNGAP1-associated syndrome, a rare NDD, is marked by intellectual disability, developmental delay, epilepsy, and sleep issues. However, research on sleep quality in these individuals is limited. This study aimed to evaluate genetic variants, epilepsy, and sleep patterns in SYNGAP1-associated syndrome patients and their caregivers. METHODS: An online survey was applied to 11 caregivers of individuals diagnosed with SYNGAP1-associated syndrome. Specific clinical inquiries were included, addressing childbirth, previous surgeries, and medication use. Inquiries about epilepsy included type of epilepsy, type and frequency of seizures, anti-seizure medications, and complementary non-pharmacological treatments. Children's Sleep Habits Questionnaire (CSHQ) was applied to assess the patients' sleep profile. Pittsburgh Sleep Quality Index (PSQI) was used to evaluate the sleep quality of caregivers. RESULTS: Genetic analysis showed heterozygous mutations in SYNGAP1, often leading to loss of function. Epilepsy was present in 82% of participants, with 77.8% having drug-resistant seizures. Using the Children's Sleep Habits Questionnaire (CSHQ), 81.8% of patients exhibited poor sleep habits, including bedtime resistance, anxiety, night awakenings, parasomnias, and daytime sleepiness. Caregivers also reported poor sleep quality according to the Pittsburgh Sleep Quality Index (PSQI). CONCLUSIONS: This study highlights the high prevalence of epilepsy and sleep problems in SYNGAP1-associated syndrome, impacting both patients and caregivers. Further research is crucial to understand the syndrome's effects on sleep disturbances, emphasizing the need for targeted interventions to improve sleep quality in individuals with rare genetic syndromes and their caregivers.

4.
Amino Acids ; 56(1): 35, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38698213

RESUMO

Chagas disease, caused by the protozoa Trypanosoma cruzi, continues to be a serious public health problem in Latin America, worsened by the limitations in its detection. Given the importance of developing new diagnostic methods for this disease, the present review aimed to verify the number of publications dedicated to research on peptides that demonstrate their usefulness in serodiagnosis. To this end, a bibliographic survey was conducted on the PubMed platform using the keyword "peptide" or "epitope" combined with "Chagas disease" or "Trypanosoma cruzi"; "diagno*" or "serodiagnosis" or "immunodiagnosis", without period restriction. An increasing number of publications on studies employing peptides in ELISA and rapid tests assays was verified, which confirms the expansion of research in this field. It is possible to observe that many of the peptides tested so far originate from proteins widely used in the diagnosis of Chagas, and many of them are part of commercial tests developed. In this sense, as expected, promising results were obtained for several peptides when tested in ELISA, as many of them exhibited sensitivity and specificity values above 90%. Furthermore, some peptides have been tested in several studies, confirming their diagnostic potential. Despite the promising results observed, it is possible to emphasize the need for extensive testing of peptides, using different serological panels, in order to confirm their potential. The importance of producing an effective assay capable of detecting the clinical stages of the disease, as well as new immunogenic antigens that enable new serological diagnostic tools for Chagas disease, is evident.


Assuntos
Doença de Chagas , Ensaio de Imunoadsorção Enzimática , Peptídeos , Trypanosoma cruzi , Doença de Chagas/diagnóstico , Doença de Chagas/imunologia , Doença de Chagas/sangue , Humanos , Trypanosoma cruzi/imunologia , Peptídeos/imunologia , Peptídeos/química , Ensaio de Imunoadsorção Enzimática/métodos , Testes Imunológicos/métodos , Antígenos de Protozoários/imunologia , Antígenos de Protozoários/sangue , Testes Sorológicos/métodos
5.
Microb Cell Fact ; 23(1): 145, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38778337

RESUMO

Recombinant multiepitope proteins (RMPs) are a promising alternative for application in diagnostic tests and, given their wide application in the most diverse diseases, this review article aims to survey the use of these antigens for diagnosis, as well as discuss the main points surrounding these antigens. RMPs usually consisting of linear, immunodominant, and phylogenetically conserved epitopes, has been applied in the experimental diagnosis of various human and animal diseases, such as leishmaniasis, brucellosis, cysticercosis, Chagas disease, hepatitis, leptospirosis, leprosy, filariasis, schistosomiasis, dengue, and COVID-19. The synthetic genes for these epitopes are joined to code a single RMP, either with spacers or fused, with different biochemical properties. The epitopes' high density within the RMPs contributes to a high degree of sensitivity and specificity. The RMPs can also sidestep the need for multiple peptide synthesis or multiple recombinant proteins, reducing costs and enhancing the standardization conditions for immunoassays. Methods such as bioinformatics and circular dichroism have been widely applied in the development of new RMPs, helping to guide their construction and better understand their structure. Several RMPs have been expressed, mainly using the Escherichia coli expression system, highlighting the importance of these cells in the biotechnological field. In fact, technological advances in this area, offering a wide range of different strains to be used, make these cells the most widely used expression platform. RMPs have been experimentally used to diagnose a broad range of illnesses in the laboratory, suggesting they could also be useful for accurate diagnoses commercially. On this point, the RMP method offers a tempting substitute for the production of promising antigens used to assemble commercial diagnostic kits.


Assuntos
Epitopos , Escherichia coli , Proteínas Recombinantes , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia , Humanos , Epitopos/imunologia , Epitopos/genética , Testes Imunológicos/métodos , Animais , COVID-19/diagnóstico
6.
Curr Med Chem ; 31(30): 4763-4780, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38509682

RESUMO

Improving the diagnostic technology used to detect tegumentary leishmaniasis (TL) is essential in view of it being a widespread, often neglected tropical disease, with cases reported from the Southern United States to Northern Argentina. Recombinant proteins, recombinant multiepitope proteins, and synthetic peptides have been extensively researched and used in disease diagnosis. One of the benefits of applying these antigens is a measurable increase in sensitivity and specificity, which improves test accuracy. The present review aims to describe the use of these antigens and their diagnostic effectiveness. With that in mind, a bibliographic survey was conducted on the PudMed platform using the search terms "tegumentary leishmaniasis" AND "diagno", revealing that recombinant proteins have been described and evaluated for their value in TL diagnosis since the 1990s. However, there was a spike in the number of publications using all of the antigens between 2013 and 2022, confirming an expansion in research efforts to improve diagnosis. Moreover, all of the studies involving different antigens had promising results, including improved sensitivity and specificity. These data recognize the importance of doing research with new technologies focused on developing quick, more effective diagnostic kits as early diagnosis facilitates treatment.


Assuntos
Antígenos de Protozoários , Leishmaniose Cutânea , Proteínas Recombinantes , Antígenos de Protozoários/imunologia , Humanos , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/biossíntese , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/imunologia , Testes Imunológicos/métodos
7.
Curr Mol Med ; 2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37461338

RESUMO

BACKGROUND: Monkeypox is a global public health issue caused by the monkeypox virus (MPXV). As of October 28, 2022, a total of 77,115 laboratory-confirmed cases and 3,610 probable cases, including 36 deaths, were reported, with 9,070 cases reported in Brazil, the second most affected country. The need to develop national technologies for the rapid diagnosis of emerging diseases for mass testing of the population is evident, as observed in the SARS-CoV-2 pandemic. OBJECTIVE: With that in mind, this article provides an overview of current methods, techniques, and their applications in the molecular detection of monkeypox, focusing the search on real-time polymerase chain reaction (qPCR), polymerase chain reaction (PCR), and polymerase chain reaction-enzyme linked immunosorbent assay (PCR-ELISA). METHODS: The relevant documents or papers covered in this study were selected by a search in international bibliographic databases. The search terms used in the databases were aimed at summarizing existing knowledge on molecular diagnostic methods, such as monkeypox; MPX, MPXV, qPCR, PCR, PCR-ELISA, diagnosis and detection searched separately or together using the Boolean operator "AND" either in the title or abstract. The searches took place in September 2022, and the corresponding articles were selected between 2012 and 2022. RESULTS: We found 256 documents in total and twelve studies addressing the molecular diagnosis of monkeypox were classified as possible sources for this review. CONCLUSION: It is evident there is a pressing need to develop national technologies for rapid diagnosis of emerging diseases for mass testing of the population. It is also extremely important to have national detection kits with greater diagnostic capacity to assist in developing effective public policies in countries affected by this disease.

8.
Clocks Sleep ; 4(4): 714-721, 2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36547104

RESUMO

Sleep medicine classes and teachings are usually deficient and insufficient during undergraduate medical education. In order to circumvent the educational deficits in sleep medicine, students at a Brazilian Medical School created a sleep medicine interest group-an academic organization for teaching purposes whose administration is carried out by the undergraduate students themselves. This study aims to describe the establishment of a sleep medicine interest group, as well as to evaluate the results of its first edition on the knowledge about sleep medicine among undergraduate medical students. Classes were taken biweekly and consisted of lectures by invited professors, presentation of clinical cases, and discussion with the students. By the end of the course, both attendees and non-attendees were invited to fill out a questionnaire including an objective assessment of knowledge (15 multiple choice questions). The questionnaire was filled out by 32 participants, of which 18 were attendees and 14 were non-attendees. The average result on the final exam was significantly higher among the attendees (6.1 ± 1.2) in comparison with non-attendees (4.9 ± 1.3-p = 0.015). The results demonstrate that an interest group proved to be feasible as a source of complementary information to undergraduate medical students and a valid alternative to circumvent the educational deficits.

9.
Int J Dev Neurosci ; 82(6): 465-470, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35766866

RESUMO

INTRODUCTION: Anosmia, the loss of the sense of smell, is usually associated with rhinopathies and has been reported as a common symptom of COVID-19. There is no specific drug to treat this condition, although some evidence suggests that melatonin could promote the recovery of olfactory sensory neurons. METHODS: We set out to perform a narrative review to synthesize the current evidence in this area in respect of our hypothesis that melatonin may be linked with anosmia and play a part in oxidative stress and the regulation of inflammation. The main electronic databases (MEDLINE/PubMed, Embase, and Cochrane) were searched. RESULTS: The search produced 26 articles related to our hypothesis. Some studies examined issues related to melatonin's effects and its use as adjuvant therapy for COVID-19. Despite some studies suggesting that melatonin may have potential in the treatment of COVID-19, to the best of our knowledge, there have been no trials that have used it to treat anosmia associated with the disease. Few articles identified proposed that melatonin might have an effect on olfactory cells. DISCUSSION: Further experimental and clinical research on the role of circadian melatonin in the olfactory system is warranted. This will provide evidence of the use of melatonin in the management of anosmia. A number of identified studies suggest that the imbalanced release of melatonin by the pineal gland associated with sleep disturbance may play a role in anosmia, although the specific pathway is not yet entirely clear. This may be a base for further research into the potential role of melatonin as adjuvant treatment of anosmia.


Assuntos
COVID-19 , Melatonina , Anosmia , COVID-19/complicações , Humanos , Melatonina/farmacologia , Melatonina/uso terapêutico , Estresse Oxidativo
11.
Front Aging Neurosci ; 13: 647875, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34177550

RESUMO

Since the beginning of the COVID-19 pandemic, older adults have been found to be a highly vulnerable group, with a higher prevalence of severe cases and negative outcomes. Research has focused on the reasons why older adults are at greater risk; Sleep-related factors have been suggested as one possible explanation for this. An individual's sleep pattern undergoes significant changes over the course of their life. In older adults a specific sleep profile can be observed, one characterized by advanced sleep timing, a morningness preference, longer sleep-onset latency, shorter overall sleep duration, increased sleep fragmentation, reduced slow-wave sleep and, increased wake time after sleep onset. Additionally, an increased prevalence of sleep disorders can be observed, such as obstructive sleep apnea and insomnia. Previous research has already linked sleep disorders (especially sleep apnea) with COVID-19, but few studies have focused specifically on the older population. We believe that the intrinsic sleep patterns of older adults, and the prevalence of sleep disorders in this population, may be important factors that could explain why they are at a greater risk of negative COVID-19 outcomes. In this review, we discuss the relationship between sleep and COVID-19 among older adults, focusing on three different aspects: (1) Sleep-related issues that might increase the likelihood of getting infected by SARS-COV-2; (2) Sleep disturbances that might increase the predisposition to worse COVID-19 prognosis and outcomes; and (3) COVID-19-related aspects affecting community-dwelling older adults, such as social isolation, quarantine, and home confinement, among others, that might impact sleep.

13.
Sleep Sci ; 14(3): 193-195, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35186195
14.
J Clin Sleep Med ; 15(10): 1397-1402, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31596203

RESUMO

STUDY OBJECTIVES: The aim of the current study was to test the hypothesis that there is a temporal correlation between reflux episodes and respiratory events in patients with laryngopharyngeal reflux and obstructive sleep apnea. METHODS: Adults with clinically diagnosed laryngopharyngeal reflux confirmed by two validated instruments (reflux symptom index ≥ 13 and reflux finding score ≥ 7) and obstructive sleep apnea (OSA) underwent full polysomnography with concomitant and synchronized multichannel intraluminal impedance-pH esophageal monitoring. The apnea-hypopnea and arousal indexes that occurred 15, 30, and 45 minutes before and after each reflux episode were recorded and compared to full-night apnea and hypopnea and arousal index. RESULTS: We studied 27 patients (14 males, age 51.7 ± 9.1 years, body mass index 32.4 ± 4.2 kg/m²) with laryngopharyngeal reflux (reflux symptom index 16 ± 2 and reflux finding score 12 ± 3) and OSA (apnea-hypopnea index = 32.3 ± 28.4 events/h). We evaluated 102 reflux episodes. Almost half of the reflux episodes occurred while awake (43.1%) and only five reflux episodes (4.9%) occurred during an obstructive respiratory event. The apnea and hypopnea and arousal indexes 15, 30, and 45 minutes before and after reflux episodes were lower than full-night apnea and hypopnea and arousal indexes, respectively. CONCLUSIONS: Among patients with well-established laryngopharyngeal reflux and OSA, there is no temporal association between reflux and obstructive respiratory events. Even though the data comprised a small sample size, it seems that a more complex mechanism is involved with these two highly prevalent diseases.


Assuntos
Esôfago/fisiopatologia , Refluxo Laringofaríngeo/complicações , Refluxo Laringofaríngeo/fisiopatologia , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polissonografia , Tempo
15.
Pediatr Hematol Oncol ; 36(5): 287-301, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31287348

RESUMO

Minimal residual disease (MRD) monitoring is of prognostic importance in childhood acute lymphoblastic leukemia (ALL). The detection of immunoglobulin and T-cell receptor gene rearrangements by real-time quantitative PCR (RT-PCR) is considered the gold standard for this evaluation. However, more accessible methods also show satisfactory performance. This study aimed to compare MRD analysis by four-color flow cytometry (FC) and qualitative standard PCR on days 35 and 78 of chemotherapy and to correlate these data with patients' clinical characteristics. Forty-two children with a recent diagnosis of ALL, admitted to a public hospital in Brazil for treatment in accordance with the Brazilian Childhood Cooperative Group for ALL Treatment (GBTLI LLA-2009), were included. Bone marrow samples collected at diagnosis and on days 35 and 78 of treatment were analyzed for the immunophenotypic characterization of blasts by FC and for the detection of clonal rearrangements by standard PCR. Paired analyses were performed in 61/68 (89.7%) follow-up samples, with a general agreement of 88.5%. Disagreements were resolved by RT-PCR, which evidenced one false-negative and four false-positive results in FC, as well as two false-negative results in PCR. Among the prognostic factors, a significant association was found only between T-cell lineage and MRD by standard PCR. These results show that FC and standard PCR produce similar results in MRD detection of childhood ALL and that both methodologies may be useful in the monitoring of disease treatment, especially in regions with limited financial resources.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Citometria de Fluxo , Rearranjo Gênico do Linfócito T , Reação em Cadeia da Polimerase , Leucemia-Linfoma Linfoblástico de Células Precursoras , Receptores de Antígenos de Linfócitos T , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Neoplasia Residual , Leucemia-Linfoma Linfoblástico de Células Precursoras/sangue , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Receptores de Antígenos de Linfócitos T/sangue , Receptores de Antígenos de Linfócitos T/genética
16.
Leuk Res ; 60: 109-114, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28777950

RESUMO

BACKGROUND: Current results regarding treatment outcomes in acute myeloid leukemia (AML) point to significant differences between low- and middle-income countries (LMIC) and high-income countries (HIC). Excluding well-known socioeconomic issues, genetic markers important for prognosis have not been properly incorporated into the clinical practice so far and their usefulness outside of well-controlled clinical trials remain unknown. METHODS: Here, we assessed the clinical significance of the European LeukemiaNet (ELN) recommendations in 196 consecutive patients with AML in a real-life setting. All patients were younger than 60 years of age (49% male) and treated with conventional chemotherapy for induction and consolidation in three Brazilian Institutions that well represent Brazilian geographic and socioeconomic diversity. FINDINGS: Multivariable analysis showed that ELN recommendations had a slight association with complete remission achievement (odds ratio: 0.74, 95% confidence interval, CI: 0.53-1.01; P=0.06), but were independently associated with poor overall survival (OS) (hazard ratio, HR: 1.3, 95% CI: 1.1-1.54; P=0.002), disease-free survival (DFS) (HR: 1.42, 95% CI: 1.03-1.95; P=0.028) and event-free survival (EFS) (HR: 1.24, 95% CI: 1.06-1.47; P=0.007), considering initial leukocyte counts and age as confounders. ELN recommendations had no impact on cumulative incidence of relapse (P=0.09). INTERPRETATION: Our results suggest that within the context of LMIC, the prognostic markers recommended by ELN may be useful to predict patient's clinical outcomes; however, the OS, DFS and EFS were shorter than the reported in Europe and US for the respective risk groups.


Assuntos
Leucemia Mieloide Aguda/diagnóstico , Guias de Prática Clínica como Assunto/normas , Fatores Socioeconômicos , Adulto , Brasil , Intervalo Livre de Doença , Feminino , Humanos , Leucemia Mieloide Aguda/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Taxa de Sobrevida , Resultado do Tratamento , Adulto Jovem
17.
Mediterr J Hematol Infect Dis ; 8(1): e2016024, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27158437

RESUMO

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Current treatment strategies for childhood ALL result in long-term remission for approximately 90% of patients. However, the therapeutic response is worse among those who relapse. Several risk stratification approaches based on clinical and biological aspects have been proposed to intensify treatment in patients with high risk of relapse and reduce toxicity on those with a greater probability of cure. The detection of residual leukemic cells (minimal residual disease, MRD) is the most important prognostic factor to identify high-risk patients, allowing redefinition of chemotherapy. In the last decades, several standardized research protocols evaluated MRD using immunophenotyping by flow cytometry and/or real-time quantitative polymerase chain reaction at different time points during treatment. Both methods are highly sensitive (10(-3) a 10(-5)), but expensive, complex, and, because of that, require qualified staff and frequently are restricted to reference centers. The aim of this article was to review technical aspects of immunophenotyping by flow cytometry and real-time quantitative polymerase chain reaction to evaluate MRD in ALL.

19.
Rev Bras Hematol Hemoter ; 37(6): 373-80, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26670399

RESUMO

INTRODUCTION: Minimal residual disease is an important independent prognostic factor that can identify poor responders among patients with acute lymphoblastic leukemia. OBJECTIVE: The aim of this study was to analyze minimal residual disease using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements by conventional polymerase chain reaction followed by homo-heteroduplex analysis and to compare this with real-time polymerase chain reaction at the end of the induction period in children with acute lymphoblastic leukemia. METHODS: Seventy-four patients diagnosed with acute lymphoblastic leukemia were enrolled. Minimal residual disease was evaluated by qualitative polymerase chain reaction in 57 and by both tests in 44. The Kaplan-Meier and multivariate Cox methods and the log-rank test were used for statistical analysis. RESULTS: Nine patients (15.8%) were positive for minimal residual disease by qualitative polymerase chain reaction and 11 (25%) by real-time polymerase chain reaction considering a cut-off point of 1×10(-3) for precursor B-cell acute lymphoblastic leukemia and 1×10(-2) for T-cell acute lymphoblastic leukemia. Using the qualitative method, the 3.5-year leukemia-free survival was significantly higher in children negative for minimal residual disease compared to those with positive results (84.1%±5.6% versus 41.7%±17.3%, respectively; p-value=0.004). There was no significant association between leukemia-free survival and minimal residual disease by real-time polymerase chain reaction. Minimal residual disease by qualitative polymerase chain reaction was the only variable significantly correlated to leukemia-free survival. CONCLUSION: Given the difficulties in the implementation of minimal residual disease monitoring by real-time polymerase chain reaction in most treatment centers in Brazil, the qualitative polymerase chain reaction strategy may be a cost-effective alternative.

20.
Rev. bras. hematol. hemoter ; Rev. bras. hematol. hemoter;37(6): 373-380, Oct.-Dec. 2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-769961

RESUMO

Introduction: Minimal residual disease is an important independent prognostic factor that can identify poor responders among patients with acute lymphoblastic leukemia. Objective: The aim of this study was to analyze minimal residual disease using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements by conventional polymerase chain reaction followed by homo-heteroduplex analysis and to compare this with real-time polymerase chain reaction at the end of the induction period in children with acute lymphoblastic leukemia. Methods: Seventy-four patients diagnosed with acute lymphoblastic leukemia were enrolled. Minimal residual disease was evaluated by qualitative polymerase chain reaction in 57 and by both tests in 44. The Kaplan-Meier and multivariate Cox methods and the log-rank test were used for statistical analysis. Results: Nine patients (15.8%) were positive for minimal residual disease by qualitative polymerase chain reaction and 11 (25%) by real-time polymerase chain reaction considering a cut-off point of 1 × 10−3 for precursor B-cell acute lymphoblastic leukemia and 1 × 10−2 for T-cell acute lymphoblastic leukemia. Using the qualitative method, the 3.5-year leukemia- free survival was significantly higher in children negative for minimal residual disease compared to those with positive results (84.1% ± 5.6% versus 41.7% ± 17.3%, respectively; p-value = 0.004). There was no significant association between leukemia-free survival and minimal residual disease by real-time polymerase chain reaction. Minimal residual disease by qualitative polymerase chain reaction was the only variable significantly correlated to leukemia-free survival. Conclusion: Given the difficulties in the implementation of minimal residual disease monitoring by real-time polymerase chain reaction in most treatment centers in Brazil, the qualitative polymerase chain reaction strategy may be a cost-effective alternative.


Assuntos
Humanos , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Neoplasia Residual , Reação em Cadeia da Polimerase , Leucemia-Linfoma Linfoblástico de Células Precursoras
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