Niccolò Bolli

Monoclonal gammopathy of undetermined significance (MGUS) and clonal hematopoiesis (CH) are 2 preclinical clonal expansions of hematopoietic cells whose prevalence rises with age, reaching almost 10% in people of aged 70 years and older. The increased risk of myeloid malignancies in patients with myeloma is well defined, and the study of the association between CH and MGUS could help explain this phenomenon. Here, we analyzed a fully clinically annotated dataset of 777 older subjects (median age, 91 years) previously screened for prevalence of CH. The prevalence of MGUS and CH was 9.6% and 17.3%, respectively. We detected CH in 9.7% of the patients with MGUS and MGUS in 5.5% of the patients with CH. We did not find a significant correlation between the presence of MGUS and CH. Furthermore, the 2 conditions showed a differential association with clinical and laboratory covariates, suggesting that MGUS and CH may represent age-associated unrelated clonal drifts of hematopoietic cells. Confirmatory studies are needed to assess the relevance of CH in plasma cell disorders. This trial was registered at www.clinicaltrials.gov as #NCT03907553.