Inflammation in aging blood cells does not follow a single script. New research shows that two of the most common mutations in clonal haematopoiesis—DNMT3A and TET2—set off inflammation, but each mutation uses a different biological route. This challenges the idea that all age-related blood disorders work the same way.
CHIP-associated variants can reach 10% to 40% variant allele frequency or higher in blood, indicating substantial clonal expansion rather than trace-level mosaicism.
TET2 mutations work differently. These cells do not wake up the dark genome. Instead, TET2-mutant cells show little activity from retrotransposable elements. Their inflammation comes from changes in cell metabolism and more oxidative stress. This points to a separate biological process. The split between DNMT3A and TET2 mutations breaks the old idea that there is just one inflammatory pathway in clonal haematopoiesis. Reviews from 2026 still name DNMT3A and TET2 as the two most common CHIP mutations and describe them as main drivers of pro-inflammatory myeloid states, backing up the study's main point.
Clonal haematopoiesis means mutated blood stem cells multiply, so many blood cells end up with the same genetic change. This is a known risk factor for blood cancers, heart disease, and atrial fibrillation. DNMT3A and TET2, the two most common mutations, both control which parts of the genome are turned on or off. The new data shows that when these genes are disrupted, inflammation follows—but the molecular chain of events is different for each. Independent 2026 research keeps linking CHIP, especially TET2 and DNMT3A, to stronger systemic inflammatory signals like IL-6 and TNF-α. This matches the article’s claim that these mutations drive inflammation through different routes, as detailed in a Frontiers in Genetics review.
A 2026 review on aging and DNA damage response again frames DNMT3A and TET2 as canonical CHIP genes that promote clonal expansion, indicating the topic remains active in the literature rather than being a one-off finding.
For DNMT3A, the evidence is strong. Mutations disrupt DNA methylation, which normally keeps retrotransposable elements silent. When this control fails, these elements switch on and trigger inflammation. The bigger the DNMT3A-mutant clone, the stronger the effect. TET2 mutations do not cause the same dark genome activity. Instead, they change the cell’s metabolism and increase oxidative stress, leading to inflammation by another route.
These differences matter. The study’s authors say that activation of retrotransposable elements could become a biomarker for disease risk in people with DNMT3A mutations. If future work proves that this activation directly causes inflammation, it could be a target for new treatments. Dr Karimi says the goal is to find out if targeting these specific inflammatory pathways can help prevent or treat disease in people with clonal haematopoiesis.
This research, funded by Celgene (a Bristol Myers Squibb company) and King's Health Partners, marks a step forward in understanding the molecular roots of age-related blood disorders. By showing how DNMT3A and TET2 mutations set off different inflammatory mechanisms, the study points to more precise biomarker development and possible mutation-specific treatments. The old one-size-fits-all approach to clonal haematopoiesis is fading. The future will depend on decoding the unique molecular fingerprints of each mutation and turning them into real clinical strategies.
