Normal B Cells in MBL follow divergent maturation pathways that correlate with the IGHV mutation status of the pre-leukemic clone

作者：Gonzalo Blanco, Xiao‐Jie Yan, Anita Ng, Andrew Shih, Jacqueline Aldridge, Anna Puiggros, Lindybeth Sarmiento, Jonathan E. Kolitz, Steven L. Allen, Kanti Rai, Douglas R. Stewart, Blanca Espinet, Gerald E. Marti, Neil E. Caporaso, Marcelo A. Navarrete, Nicholas Chiorazzi · 发表于：Blood · 年份：2025 · DOI：10.1182/blood-2025-3910 · 被引用次数：1 · 研究领域：Chronic Lymphocytic Leukemia Research、CAR-T cell therapy research、T-cell and Retrovirus Studies

Abstract CLL and its precursor, monoclonal B-cell lymphocytosis (MBL), are associated with immune deficits. In MBL, the higher percentages of normal B cells (NBC) provide a unique opportunity to study B-cell defects. We compared transcriptomes of NBC from healthy donors (HD) and people with high-count MBL (hcMBL) with mutated (M-MBL) and unmutated (U-MBL) IGHV, and with low-count MBL (lcMBL). We also explored B-cell subset distribution and BCR repertoires. PBMC were collected from 21 hcMBL (12 M-MBL, 9 U-MBL), 7 lcMBL (1 M-MBL, the rest unknown), and 13 HD. 111 sorted B-cell samples were obtained: 21 hcMBL clones (CD20LowCD5+Igκ+/Igλ+), 36 NBC-hcMBL (30 CD20+CD5⁻; 6 CD20+CD5⁺), 12 NBC-lcMBL (CD20+CD5⁻), and 42 NBC-HD (25 CD20+CD5⁻; 17 CD20+CD5⁺). RNA was sequenced using SMART-Seqv4 on HiSeq. Differentially expressed genes (DEG) were analyzed with DESeq2 (Padj<0.05, |FC|≥1.5). Transcriptome variation was assessed by PCA and enriched pathways by IPA. Flow cytometry validated DEG in 6 hcMBL and 8 HD. B-cell subset distribution was analyzed in 14 hcMBL (10 M-MBL, 4 U-MBL) and 9 HD using FACSymphony. BCR repertoire analysis was performed on NBCs of 4 HD, 7 hcMBL (4 M-MBL, 3 U-MBL), and 1 M-lcMBL patient, using the ImmunoRead platform and a custom pipeline built upon the Immcantation framework. Leukemic IGHV-D-J reads were removed. PCA clearly separated NBC-HD, NBC-lcMBL, NBC-hcMBL, and hcMBL clones, forming a gradient with NBC-HD and hcMBL clones at opposite extremes, and N...