BONE MARROW INVOLVEMENT ANALYSIS USING IGH AND TCR GENE REARRANGEMENT IN MALIGNANT LYMPHOMA

초록

Introduction: The assessment of bone marrow involvement(BMI) is a clinical procedure for newly diagnosed lymphoma pa-tients. BMI represents an extra-nodal manifestation, and it hasbeen associated with an unfavorable prognosis. Consequently,accurately detecting BMI plays a crucial role in both prognosis prediction and the formulation of treatment strate-gies. Conventional methods for BMI assessment involve themorphological evaluation of bone marrow aspirate and biopsyspecimens. Our study evaluated the feasibility and effective-ness of using IGH or TCR gene analysis through PCR and next-generation sequencing (NGS) in BMI evaluation, comparingthem to the conventional morphological approaches. Methods:A total of 124 B-cell lymphoma and 21 T-cell lymphoma patients,all diagnosed between January 2019 and June 2022 with suffi-cient follow-up periods, were included in the study. To assess Igclonality, DNA isolated from bone marrow aspirates was sub-jected to multiplex PCR and next-generation sequencing (NGS)using the LymphoTrak IGH FR1 Assay, IGK Assay, and theIllumina MiSeq platform. TCR clonality analysis was conductedemploying the TRB and TRG Assay (Invivoscribe Technologies,San Diego, CA). Clonality was assessed using LymphoTrack DxData Analysis software (version 2.4.3), following the manufac-turer's guidelines for IGH, IGK, and TCR. These results werethen compared to the morphological evaluation of bone marrowaspirate and biopsy slides. Result: Among the 145 patients, mor-phological evaluation identified BMI in 15.3% (n = 23) of them.The rates of clonality for IGH and IGK were 17.7% (n = 22) and16.1% (n = 20) respectively, with a combined clonality of 22.6%(n = 28) for either IGH or IGK. The positive rates of TCR beta andTCR gamma gene rearrangements were 66.6% (n = 14) and 76.1%(n = 16) respectively, with a total of 85.7% (n = 18) of patients witheither TCR beta or gamma clonality. Of note, among patientswho initially received negative pathology reports, 10.4% of thosewith B-cell lymphoma (11/105), and 53.8% of those with T celllymphoma (7/13) were subsequently found to be positive by PCRor NGS. The patients exhibiting IGH clonality showed inferioroutcomes with shorter progression-free survival (PFS) (p < 0.001and shorter overall survival (OS) (p = 0.008), compared to pa-tients without IGH clonality. Conclusion: Clonality analysisusing PCR and NGS yielded a higher detection frequency ofBMI compared to morphological assessment. Notably, the pos-itive rates of clonality assessment for both IGH and TCR weresignificantly higher than those detected through morphologicalmethods. These results underscore the utility of IGH and TCRclonality assessment in identifying BMI in lymphoma cases,even in the absence of morphological evidence.