RESUMO
Short tandem repeat (STR) analysis is used in chimerism monitoring after allogeneic hematopoietic stem cell transplantation (HSCT) for patients with various hematologic malignancies. Commercial forensic STR kits often contain loci with huge differences in power of discrimination (PD) across populations, causing some loci to be less informative for chimerism analysis in certain populations. This study aimed to construct a new STR multiplex panel with highly informative loci for efficient chimerism analysis. Thirteen STR markers which exhibit high PD (> 0.9) in at least 80% of 50 populations globally were selected to form a new panel and used in STR analysis of 253 Malaysian subjects. Cumulative power of discrimination (CPD) and combined power of exclusion (CPE) were determined from 253 Malaysian individuals. Loci informativity was assessed and compared to the commercial AmpFLSTR Identifiler PCR Amplification kit in 14 donor-recipient pairs. The new panel had detected 202 unique alleles including five novel alleles from the 253 individuals with high CPD and CPE (> 0.99999999999999999 and > 0.999999997 respectively). All loci from the new panel in the donor-recipient pair analysis showed higher than 50% informativity, while five loci from the commercial kit demonstrated lower than 50% informativity. Four loci from the new panel ranked the highest informativity. A sequenced allelic ladder which consists of 202 unique alleles from the 253 subjects was also developed to ensure accurate allele designation. The new 13-loci STR panel, thus, could serve as an additional powerful, accurate, and highly informative panel for chimerism analysis for HSCT patients.
Assuntos
Loci Gênicos , Transplante de Células-Tronco Hematopoéticas , Repetições de Microssatélites , Reação em Cadeia da Polimerase Multiplex , Kit de Reagentes para Diagnóstico/normas , Quimeras de Transplante/genética , Aloenxertos , Feminino , Humanos , Malásia , Masculino , Reação em Cadeia da Polimerase Multiplex/métodos , Reação em Cadeia da Polimerase Multiplex/normas , Quimeras de Transplante/sangueRESUMO
BACKGROUND: Occult hepatitis B infections are becoming a major global threat, but the available data on its prevalence in various parts of the world are often divergent. OBJECTIVE: This study aimed to detect occult hepatitis B virus in hepatitis B surface antigen-negative serum using anti-HBc as a marker of previous infection. PATIENT AND METHODS: A total of 1000 randomly selected hepatitis B surface antigen-negative sera from blood donors were tested for hepatitis B core antibody and hepatitis B surface antibody using an ELISA and nested polymerase chain reaction was done using primers specific to the surface gene (S-gene). RESULTS: Of the 1000 samples 55 (5.5%) were found to be reactive, of which 87.3% (48/55) were positive for hepatitis B surface antibody, indicating immunity as a result of previous infection however, that does not exclude active infection with escaped mutant HBV. Nested PCR results showed the presence of hepatitis B viral DNA in all the 55 samples that were positive for core protein, which is in agreement with the hepatitis B surface antibody result. CONCLUSION: This study reveals the 5.5% prevalence of occult hepatitis B among Malaysian blood donors as well as the reliability of using hepatitis B core antibody in screening for occult hepatitis B infection in low endemic, low socioeconomic settings.
Assuntos
Doadores de Sangue , Antígenos de Superfície da Hepatite B/sangue , Vírus da Hepatite B/isolamento & purificação , Hepatite B/diagnóstico , Ensaio de Imunoadsorção Enzimática , Hepatite B/epidemiologia , Anticorpos Anti-Hepatite B/sangue , Antígenos de Superfície da Hepatite B/genética , Humanos , Malásia/epidemiologia , Reação em Cadeia da Polimerase , PrevalênciaRESUMO
Eighty-eight multi-ethnic Malaysian pediatric acute lymphoblastic leukemia (ALL) patients were screened for the TEL-AML1 rearrangement by reverse transcription-polymerase chain reaction (RT-PCR). Fluorescence in situ hybridization (FISH) was used as an independent screen for 30 cases and to confirm RT-PCR positive cases. Seventeen patients, or 19%, were found to be t(12;21) positive. Ethnically the group comprised 12 Malays, 4 Chinese, and 1 Indian. All patients, including 1 with an unusual blast cell morphology who suffered an early relapse and death, were characteristic TEL-AML1 cases in cell count, age, ALL subset classification, and fusion transcript expressed. This study shows that in Malaysia, TEL-AML1 is found in the same distinct ALL subset and at a similar frequency as in other diverse childhood ALL cohorts.
Assuntos
Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Medula Óssea/patologia , Criança , Pré-Escolar , China/etnologia , Subunidade alfa 2 de Fator de Ligação ao Core , Etnicidade/genética , Feminino , Rearranjo Gênico , Humanos , Imunofenotipagem , Índia/etnologia , Malásia , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
An RT-PCR assay detected the t(4;11) translocation in two infants with acute lymphoblastic leukemia (ALL). Case P76 was a 10-month-old, female infant, who presented with a WBC of 137.4 x 10(9)/l and a pre-pre-B ALL immunophenotype. Case P120 was a 6-month-old female infant, with a WBC > 615 x 10(9)/l and a pre-pre-B ALL immunophenotype. RT-PCR of cDNA from both these cases generated a 656 bp and a 542 bp respectively, which sequencing confirmed as t(4;11) fusion transcripts. The primers and conditions selected for this assay are compatible with a one-step multiplex PCR for the main translocations in childhood ALL.