Detection of Immunoglobulin Heavy Chain Gene Clonality by Next-Generation Sequencing for Minimal Residual Disease Monitoring in B-Lymphoblastic Leukemia

Minimal residual disease (MRD) following B-lymphoblastic leukemia (B-ALL) treatment has gained prognostic importance. Clonal immunoglobulin heavy chain (IGH) gene rearrangement is a useful follow-up marker in B-ALL owing to its high positivity rate. We evaluated the performance and clinical applicability of a next-generation sequencing (NGS) assay for IGH rearrangement in B-ALL MRD monitoring. IGH rearrangement was tested by using fluorescence PCR-fragment analysis and the NGS assay in eight B-ALL patients. The NGS assay was run on two platforms: the Ion Torrent PGM (Thermo Fisher Scientific, USA) (18 samples from 1st to 7th patients) and the MiSeq system (Illumina, USA) (four samples from 8th patient). All initial diagnostic samples and four follow-up samples were positive for clonal IGH rearrangement with fluorescence PCR-fragment analysis and the NGS assay, and six follow-up samples were positive only with NGS. In one case with BCR-ABL1 translocation, BCR-ABL1 quantitative PCR was negative but the NGS IGH assay was positive just prior to full-blown relapse, suggesting the high sensitivity and clinical utility of the NGS assay. The NGS assay is proposed for MRD monitoring in B-ALL Additional studies are needed to confirm the clinical implications of cases showing positive results only in NGS.

Immunoglobulin heavy chain gene rearrangement in non B-cell haematological malignancies / Reordenamiento del gen de la cadena pesada de inmunoglobulina en las neoplasias hematológicas de linfocitos no B

PURPOSE: Clonality detection through amplifying immunoglobulin heavy chain (IGH) gene rearrangements by polymerase chain reaction (PCR) is a useful tool in diagnosis of various B-lymphoid malignancies. Immunoglobulin heavy chain gene rearrangement can be an optimal target for clonality detection in B-lymphoid malignancies. In the present study, we evaluated the presence of IGH gene rearrangement in non B-cell haemato-oncologypatients including T-cell acute lymphoblastic leukaemia (T-ALL), acute myeloblastic leukaemia (AML) and biphenotypic leukaemia. METHODS: We studied 18 cases of haematological malignancies which comprised five patients with TALL, 12 patients with AML and one with biphenotypic leukaemia. RESULTS: We found that the incidence of IGH gene rearrangement in T-ALL and AML were three (60%) and two (16.7%), respectively. The patient with biphenotypic leukaemia was negative for IGH gene rearrangement. CONCLUSION: Immunoglobulin gene rearrangement, which occurs in almost all haematological malignancies of B-cell lineage, also presents in a very small proportion of T-cell or myeloid malignancies.

OBJETIVO: La detección de la clonalidad mediante amplificación de los reordenamientos del gen de la cadena pesada (IGH) de inmunoglobulina por reacción en cadena de la polimerasa (RCP) es una herramienta útil en el diagnóstico de varios tumores malignos linfoides de células B. El reordenamiento del gen de la cadena pesada de inmunoglobulina puede ser un objetivo óptimo de la detección de la clonalidad en tumores malignos linfoides de células B. En el presente estudio, se evaluó la presencia de reordenamiento del gen IGH en pacientes de hemato-oncología de células no B, incluyendo la leucemia linfoblástica aguda de células T (LLA-T), leucemia mieloblástica aguda (LMA), y leucemia bifenotípica. MÉTODOS: Se estudiaron 18 casos de neoplasias malignas hematológicas que abarcaron cinco pacientes con (LLA-T), 12pacientes con AML y uno con leucemia bifenotípica. CONCLUSIÓN: Reordenamiento del gen de la inmunoglobulina que ocurre en casi todas las neoplasias malignas hematológicas del linaje de las células B, también se presenta en una proporción muy pequeña de células T o las neoplasias mieloides.

Comparison of the Rate of Detection of Immunoglobulin Heavy Chain Gene Rearrangement by Fluoresecence In Situ Hybridization Probes in Multiple Myeloma / 대한진단검사의학회지

BACKGROUND: Immunoglobulin heavy chain (IgH) gene rearrangement, which is frequently observed in multiple myeloma, can now be detected easily by using a fluorescence in situ hybridization (FISH) method. The aim of this study was to determine the detection rate and compare the utility of the three most commonly used probes: IGH/CCND1 dual color, dual fusion probe; IGH/BCL2 dual color, dual fusion probe; and IGH dual color break apart rearrangement probe; all from Vysis Products (Downers Grove, IL, USA). METHODS: From October 1994 to July 2003, 99 patients were diagnosed as multiple myeloma at Seoul National University Hospital, Asan Medical Center and Gachon University Gil hospital. We applied the three different probes of IgH FISH on bone marrow specimens from the 99 Korean patients with multiple myeloma to detect IgH gene rearrangement. RESULTS: Forty-one (41.4%) of the 99 patients had IgH gene rearrangement. Of those 41 patients, 23 (56.1%) showed positive to all three probes, but the remaining 18 (43.9%) showed a discrepancy between the three probes: 13 (72.2%) of the 18 patients were only positive to the IGH dual color break apart rearrangement probe and the detection rate was 39.6% on the average. CONCLUSIONS: These results demonstrate that IGH dual color break apart rearrangement probe is superior to the other two probes in qualitative and quantitative ways. Thus, we recommend IGH dual color break apart rearrangement probe for the diagnosis and monitoring of multiple myeloma.