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Updated: Sep 29, 2025
Immunoglobulin Gene Sequence Analysis In Chronic Lymphocytic Leukemia: From Patient Material To Sequence Interpretation
Published on: November 26, 2018
Unmutated IGHV1-69 CLL Clone Displays a Distinct Gene Expression Profile by a Comparative qRT-PCR Assay
Selena Mimmi1, Domenico Maisano1, Vincenzo Dattilo2
1Laboratory of Immunology, Department of Experimental and Clinical Medicine, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy.
Insights
Chronic Lymphocytic Leukemia (CLL) clones expressing IGHV1-69 show increased survival gene expression, suggesting an evolutionary advantage. This finding aids in understanding aggressive CLL clones and developing personalized therapies.
Area of Science:
- Hematology
- Oncology
- Molecular Biology
Background:
- Chronic Lymphocytic Leukemia (CLL) exhibits heterogeneous clinical courses.
- Coexisting CLL clones within patients can have different biological behaviors.
- B-cell receptor immunoglobulin (BcR IG) idiotypic sequences help identify distinct CLL clones.
Purpose of the Study:
- To investigate the biological and molecular characteristics of aggressive and drug-resistant CLL clones.
- To explore if IGHV1-69 CLL clones possess an evolutionary advantage.
- To identify genes involved in survival and apoptosis escape in persistent CLL clones.
Main Methods:
- Selected a peptide binder for CLL BcR IGs expressing IGHV1-69 using phage display.
- Used peptide-based cell sorting by flow cytometry on peripheral blood samples.
- Analyzed gene expression patterns of apoptosis regulation and NF-kB signaling pathways via qRT-PCR.
Main Results:
- IGHV1-69 CLL clones demonstrated higher expression of pro-survival and anti-apoptotic genes compared to other CLL clones.
- These aggressive clones lacked characteristic genetic lesions.
- The findings highlight the utility of clone-specific molecular characterization.
Conclusions:
- IGHV1-69 CLL clones may have an evolutive advantage due to enhanced expression of survival genes.
- This approach facilitates comprehensive molecular characterization of individual tumor clones.
- Personalized therapeutic strategies can be designed for aggressive and persistent CLL clones.
Abstract:
Chronic Lymphocytic Leukemia (CLL) is a heterogeneous disease characterized by variable clinical courses among different patients. This notion was supported by the possible coexistence of two or more independent CLL clones within the same patients, identified by the characterization of the B cell receptor immunoglobulin (BcR IG) idiotypic sequence. By using the antigen-binding site of the BcR IG as bait, the identification and isolation of aggressive and drug-resistance leukemic B-cell clones could allow a deeper biological and molecular investigation. Indeed, by the screening of phage display libraries, we previously selected a peptide binder of the idiotypic region of CLL BCR IGs expressing the unmutated rearrangement IGHV1-69 and used it as a probe to perform a peptide-based cell sorting by flow cytometry in peripheral blood samples from patients with CLL. Since the IGHV1-69 clones persisted during the follow-up time in both patients, we explored the possibility of these clones having acquired an evolutive advantage compared to the other coexisting clones in terms of a higher expression of genes involved in the survival and apoptosis escape processes. To this end, we studied the expression patterns of a panel of genes involved in apoptosis regulation and in NF-kB-dependent pro-survival signals by comparative qRT-PCR assays. According to the results, IGHV1-69 clones showed a higher expression of pro-survival and anti-apoptotic genes as compared to the other CLL clones with different immunogenetic characteristics. Moreover, these IGHV1-69 clones did not carry any characteristic genetic lesions, indicating the relevance of our approach in performing a comprehensive molecular characterization of single tumor clones, as well as for designing new personalized therapeutic approaches for the most aggressive and persistent tumor clones.
