Monocytosis and its association with clonal hematopoiesis in community-dwelling individuals

Skin autofluorescence, a measure for accumulation of advanced glycation end products, positively associates with blood neutrophil and monocyte counts in the general population, and particularly in men with prediabetes

BACKGROUND AND AIMS

Previous studies have shown that skin autofluorescence (SAF), measured with an advanced glycation end product (AGE) reader, estimates the accumulation of AGEs in tissues. SAF is predictive of incident type 2 diabetes, cardiovascular disease (CVD), and CV mortality in the general population. Studies in diabetic mice have shown that activation of the receptor for AGEs in hematopoietic progenitor cells increases blood neutrophils and monocytes, impairing atherosclerosis regression. We asked whether SAF is associated with blood neutrophil and monocyte counts in the general population, and whether this was moderated by prediabetes, diabetes, and sex.

METHODS

We examined the associations between SAF and blood neutrophil/monocyte counts in participants of the Lifelines cohort (n = 58,923: n = 24,382 men, and n = 34,541 women), a prospective population-based cohort from the North of the Netherlands, employing multivariable regression analyses.

RESULTS

SAF positively associated with blood neutrophil and monocyte counts in the whole cohort. The positive association between SAF and monocyte, but not neutrophil, counts was moderated by prediabetes and diabetes. Positive associations between SAF and blood neutrophil and monocyte counts were moderated by male sex. Moreover, three-way interaction analyses revealed that the positive associations between SAF and neutrophil and monocyte counts were moderated by prediabetes, but not diabetes, in male sex.

CONCLUSIONS

SAF is positively associated with blood neutrophil and monocyte counts in the general population, especially in men with prediabetes. This may contribute to the increased CV risk in men with prediabetes.

Evolutionary landscape of clonal hematopoiesis in 3,359 individuals from the general population

Knowledge about evolution of clonal hematopoiesis, which may drive malignant progression, is crucial for clinical decision-making. We investigated the landscape of clonal evolution by error-corrected sequencing on 7,045 sequential samples from 3,359 individuals in the prospective population-based Lifelines cohort, with a special focus on cytosis and cytopenia. Spliceosome (SRSF2/U2AF1/SF3B1) and JAK2 mutated clones show highest growth rates over a median 3.6-year period, while clone sizes for DNMT3A and TP53 increase only marginally, independent of cytosis or cytopenia. Nevertheless, large differences are observed between individuals carrying the same mutation, indicative of modulation by non-mutation-related factors. Clonal expansion is not dependent on classical cancer risk factors (e.g., smoking). Risk for incident myeloid malignancy diagnosis is highest for JAK2, spliceosome, or TP53 mutations and absent for DNMT3A, and it is mostly preceded by cytosis or cytopenia. The results provide important insight into high-risk evolutionary patterns to guide monitoring of "CHIP" and "CCUS."

Abnormal Platelet Counts and Clonal Hematopoiesis in the General Population

Clonal hematopoiesis (CH) is defined by the presence of somatic mutations that may cause clonal expansion of hematopoietic cells. Here, we investigated the association between platelet count abnormalities, CH and consequences on overall survival and the development of hematological malignancies. Individuals with thrombocytopenia (n = 631) or thrombocytosis (n = 178) ≥60 years, and their age- and sex-matched controls, were selected within the population-based Lifelines cohort (n = 167,729). Although the prevalence of CH was not increased in thrombocytopenia cases compared with their controls (37.9% vs 39.3%; P = 0.639), mutations in spliceosome genes (SF3B1, SRSF2, U2AF1) were significantly enriched in thrombocytopenia cases (P = 0.007). Overall, CH in combination with thrombocytopenia did not impact on survival, but thrombocytopenia in combination with multiple mutated genes (hazard ratio [HR] = 2.08, 95% confidence interval [CI], 1.24-3.50; P = 0.006), mutations in TP53 (HR = 5.83, 95% CI, 2.49-13.64; P < 0.001) or spliceosome genes (HR = 2.69, 95% CI, 1.29-5.63; P = 0.009) increased the risk of death. The prevalence of CH in thrombocytosis cases was higher compared with controls (55.8% vs 37.7%; P < 0.001). Especially mutations in JAK2 (P < 0.001) and CALR (P = 0.003) were enriched in individuals with thrombocytosis. The presence of CH in individuals with thrombocytosis did not impact on overall survival. However, during follow-up of 11 years 23% of the individuals with thrombocytosis and CH were diagnosed with hematological malignancies. From these, 81% were diagnosed with myeloproliferative disease and 76% carried driver mutations JAK2, CALR, or MPL.

Clonal Hematopoiesis: Role in Hematologic and Non-Hematologic Malignancies

Hematopoietic stem cells (HSCs) ensure the coordinated and balanced production of all hematopoietic cell types throughout life. Aging is associated with a gradual decline of the self-renewal and regenerative potential of HSCs and with the development of clonal hematopoiesis. Clonal hematopoiesis of indeterminate potential (CHIP) defines the clonal expansion of genetically variant hematopoietic cells bearing one or more gene mutations and/or structural variants (such as copy number alterations). CHIP increases exponentially with age and is associated with cancers, including hematologic neoplasia, cardiovascular and other diseases. The presence of CHIP consistently increases the risk of hematologic malignancy, particularly in individuals who have CHIP in association with peripheral blood cytopenia.