RESUMEN
High-sensitivity multicolour flow cytometry (MFC)-based B-lymphoblastic leukaemia (B-ALL) measurable residual disease (BMRD) assay is increasingly being used in clinical practice. Herein, we describe six consistently present low-level populations immunophenotypically mimicking abnormal B-ALL blasts in 441 BMRD samples from 301 children. These included CD19+ CD123+ plasmacytoid dendritic cells differentiating from lymphoid precursors, CD10+ transitional B cells with CD10+ /CD38dim-to-negative/CD20bright/CD45bright phenotype, CD19+ natural killer (NK) cells, CD73bright/CD10+ mesenchymal stromal/stem cells, CD73bright/CD34+ endothelial cells, and a CD34+ CD38dim-to-negative/CD10- /CD20bright/CD45bright subset of mature B cells. We provide the proportions, comprehensive immunophenotype, and practical clues for proper identification of these low-level populations. Knowledge regarding the presence and immunophenotype of these mimics is essential for accurate interpretation in high-sensitivity MFC-BMRD analysis.
Asunto(s)
Citometría de Flujo/métodos , Inmunofenotipificación/métodos , Neoplasia Residual/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Artefactos , Biomarcadores de Tumor , Toma de Decisiones Clínicas , Manejo de la Enfermedad , Citometría de Flujo/normas , Humanos , Inmunofenotipificación/normas , Quimioterapia de Inducción , Leucemia-Linfoma Linfoblástico de Células Precursoras B/etiología , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Pronóstico , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Resultado del TratamientoRESUMEN
Human parvovirus B19 (B19V) has been associated with chronic anemia in immuno-compromised patients. In the present study, the prevalence and genotype distribution of B19V in children from North India, suffering with hemato-oncological disorders is reported. Children with aplastic anemia/leukemia/chronic hematological disorders, and healthy blood donors were enrolled in the study. Blood samples from cases and blood donors were analyzed for anti-B19V IgM and anti-B19V IgG antibodies by ELISA and for B19V-DNA by PCR. B19V-DNA positive samples were studied further for determination of viral load in samples and for B19V-DNA sequence (VP1/VP2 overlapping region) analysis. Total 238 cases (103 leukemia, 77 aplastic anemia and 58 chronic hematological disorders) and 350 blood donors were enrolled in the study. Anti-B19V IgM was positive in 16 (6.7%) cases, B19V-DNA was detected in 13 (5.5%) cases and anti-B19V IgG was positive in 127 (53.4%) cases. Total 223 (63.5%) blood donors were positive for anti-B19V IgG, however, anti-B19V IgM and B19V-DNA was not detected in any blood donor. The prevalence of anti-B19V IgG was significantly higher in children > 10 years of age. Viral load of B19V decreased with appearance of specific antibodies. Phylogenetic analysis of the VP1/VP2 overlapping region revealed that genotype 1 predominated in these patients (11/13, 84.6%), followed by genotype 3 (2/13, 15.4%). No genotype 2 was detected. All the genotype 1strains were sub-typed as 1a, except four strains, which matched neither 1a nor 1b and formed a separate cluster. Both the genotype 3 strains were sub-typed as 3b.