St Anna Children's Hospital

Abstract Retrospective reconstruction of cell lineages from somatic mutations holds substantial promise for understanding development, tissue homeostasis, and disease. Yet, current approaches are often constrained by low marker density, technical noise, and incomplete molecular readouts that limit the resolution and accuracy of inferred lineages. Here, we present RETrace2, a single-cell dual-omic method for simultaneous lineage tracing and cell-type identification. By identifying and targeting highly mutable homopolymers, which we show are approximately twice as informative as conventional microsatellite repeats, combined with technical improvements to increase marker coverage and reduce experimental errors of reading and amplifying homopolymers, RETrace2 can trace lineage continuously at an estimated resolution of fewer than five cell divisions in microsatellite-unstable organisms. Simultaneously, sparse methylation profiles were obtained from the same cells for cell-type identification. We validated the method using in vitro ground-truth models and demonstrated its utility in vivo by reconstructing multi-organ lineage trees from the brain, kidney and liver of Msh2 -deficient mice.

Prospective data of a large randomized multi-international leukaemia trial revealed an incidence of 1.1% of invasive yeast infections (IYIs) in children with acute lymphoblastic leukaemia. IYIs occurred predominantly during induction chemotherapy, presented as bloodstream infection ± tissue involvement, were due to a variety of yeast and had an attributable mortality of 5.9%.

This study provides the first historical reconstruction of metal and metalloid deposition in Slovakia using bryophyte herbarium specimens. By integrating archival and contemporary data, we established a dataset for Bratislava spanning 1912-2023, enabling evaluation of temporal and spatial pollution trends, emission sources, and comparisons with European patterns. The investigation covers three major periods (1900-1945, 1946-1989, 1990-2023), reflecting key stages in industrial and transportation development. Concentrations of 22 elements, measured by inductively coupled plasma-mass spectrometry (ICP-MS), revealed distinct temporal trends. Metal and metalloid levels were generally low before 1945, followed by increases in As, Cd, Bi, and Pb during World War II and peak accumulation during the industrialization of 1946-1989. A marked decline in Pb, Cd, As, Tl, and Ba after 1990 indicates industrial downturn and the effectiveness of environmental regulations, consistent with European trends. In contrast, recent samples showed elevated Cr, Ni, Mo, and Cu, linked to traffic and ongoing industrial emissions. Statistical analyses identified six groups of elements associated with distinct anthropogenic sources. Spatial patterns indicated that the highest concentrations occurred near historical and current point sources, with proximity to emissions and prevailing wind direction significantly influencing distributions. The use of herbarium specimens allowed reconstruction of the long-term environmental impacts of industrialization and urbanization in a Central European capital. The results establish a historical baseline for assessing ecosystem recovery and provide valuable data to support future environmental management and public health policies.

Backgroung and Aimes: Juvenile myelomonocytic leukemia (JMML) is a rare, aggressive pediatric myeloproliferative neoplasm for which hematopoietic stem cell transplantation (HSCT) is currently the only established curative therapy.However, a watch-and-wait (W&W) approach has shown promise for long-term survival in selected cases.Methods: This real-life study assessed the outcomes of JMML patients managed with a W&W strategy in a nationwide cohort of 161 genetically characterized cases.Clinical and molecular data were analyzed to identify prognostic factors that could guide patient selection for the W&W approach.Results: Between 2001 and 2021, the W&W strategy was implemented in 35 out of 161 patients (22%), with a significant increase over time.Notably, more than one-third of patients received W&W management between 2016 and 2021.Most patients had mutations in CBL (43%), NRAS (34%), or SH2B3 (14%).Over a median follow-up of 6.5 years, 86% (30/35) achieved long-term survival with partial or complete resolution of myeloproliferative symptoms.In 28/30 long term survivors, clonal hematopoiesis with stable variant allele frequencies persisted while two showed a decrease in mutation burden.Five patients (CBL: n=3, NRAS: n=1, PTPN11: n=1) experienced disease progression mostly within two years post-diagnosis (4/5).Among them, three underwent HSCT and are currently alive while two were lost of follow up and died of disease.In CBL and homozygous germline SH2B3, no predictive factor of adverse outcomes were identified.In NRAS patients, younger age <30 months, normal to slightly elevated fetal hemoglobin, no additional somatic mutations, and low DNA methylation profile were associated with long-term survival.Conclusions: W&W is a feasible alternative for patients with CBL, NRAS and homozygous germline SH2B3, potentially sparing them from HSCT-associated risks.However, given the uncertain long-term effects of clonal hematopoiesis and possible extra-hematological complications, close monitoring remains crucial.