The immune system is one of the most intricate and fascinating systems in the human body. This complex network of organs, cells, and proteins functions tirelessly to protect us from external threats like bacteria, viruses, fungi, and other pathogens. A properly functioning immune system ensures health and defence, but it can lead to diseases, autoimmune conditions, allergic reactions, or even cancer diagnostics when compromised.
Understanding the Immune System and Clonality
The immune system’s defence mechanisms are categorised into two types: first is Innate Immunity: It is present since birth and is a rapid system acting against pathogens but nonspecific. The second one is Adaptive Immunity, developed in response to exposure to specific pathogens.
The adaptive immune system relies heavily on white blood cells, specifically B cells and T cells, which originate in the bone marrow. While B cells mature in the bone marrow, T cells complete their maturation in the thymus. A healthy immune system can generate a polyclonal population — a diverse range of B and T cell clones. This diversity is essential for recognizing and responding to the myriad of antigens encountered throughout life.
Monoclonal vs. Polyclonal Populations
While a polyclonal population indicates immune health, a monoclonal population represents the expansion of a single-cell clone. This can signify the presence of a malignant clone that multiplied uncontrollably, a characteristic often associated with cancers like leukaemia and lymphoma. These monoclonal expansions result in identical DNA sequences in the affected cells, making them reliable tumour markers.
Clonality Testing: Evolution and Techniques
Traditionally, clonality testing relied on Southern blotting, a technique used to detect rearrangements in immunoglobulin (IG) and T-cell receptor (TCR) genes. However, advancements in molecular diagnostics have made polymerase chain reaction (PCR) the gold standard for clonality assessment. PCR’s sensitivity, specificity, and rapid turnaround make it invaluable for identifying clonal rearrangements, especially in cases where conventional methods like morphology, immunohistochemistry (IHC), and flow cytometry fall short.
Key advantages of PCR-based clonality testing include: High sensitivity and specificity.
Capability to analyze small or degraded samples, including formalin-fixed paraffin-embedded (FFPE) tissues, with rapid and reproducible results.
Talking about the markers for clonality testing, Clonality assays typically focus on detecting unique IG and TCR rearrangements. These rearrangements arise from the random coupling of variable (V), diversity (D), and joining (J) gene segments, creating an almost infinite diversity of antigen receptors. This uniqueness ensures that each lymphocyte has a distinct receptor, minimizing the chance of identical receptors across different cells.
Invivoscribe delivers a wide range of PCR-based solutions for the study of hematologic malignancies, offering assays for B- and T-cell gene clonality and rearrangements, point mutations, targeted FLT3 ITD and TKD mutation assays, and chromosome translocations.
As the advancement happened in Clonality Detection, Modern clonality assays, like Invivoscribe’s LymphoTrack® developed with leading NGS platforms, have revolutionized the field. These assays leverage next-generation sequencing (NGS) for unmatched accuracy and detailed insights into clonal populations. Key benefits include: Identification of clonality with high precision, detailed sequence analysis, including somatic hypermutation rates, tracking of measurable residual disease (MRD), crucial for monitoring therapy response and remission in lymphoproliferative disorders.
Clinical Applications and Future Directions
The ability to distinguish between benign and malignant lymphoid proliferations remains challenging in 10–15% of cases. Clonality testing, when integrated with clinical, morphological, and genetic data, enhances diagnostic accuracy. Advanced assays like LymphoTrack® not only confirm clonality but also provide comprehensive data for monitoring disease progression and therapeutic efficacy. Invivoscribe offers LymphoTrack MRD Bundled Solution, which consists of assay reagents along with an internal control, a low positive control, and bioinformatics software.
In conclusion, Clonality testing has come a long way, from Southern blotting to advanced NGS-based techniques. At DSS ImageTech , we provide the latest solutions to empower researchers and clinicians in better understanding, classifying, and treating haematological malignancies. These advancements, supported by DSS ImageTech cutting-edge technology, are shaping the future of precision oncology. As technology continues to evolve, clonality assays will undoubtedly play an even more pivotal role in precision oncology , paving the way for more targeted and effective therapies.
