B-cell acute lymphoblastic leukemia (B-ALL) is a serious public health problem in the pediatric population worldwide, contributing to 85% of deaths from childhood cancers. Understanding the biology of the disease is crucial for its clinical management and the development of therapeutic strategies. In line with that observed in other malignancies, chronic inflammation may contribute to a tumor microenvironment resulting in the damage of normal processes, concomitant to development and maintenance of neoplastic cells. We report here that hematopoietic cells from bone marrow B-ALL have the ability to produce proinflammatory and growth factors, including TNFα, IL-1β, IL-12, and GM-CSF that stimulate proliferation and differentiation of normal stem and progenitor cells. Our findings suggest an apparently distinct CD13+CD33+ population of leukemic cells contributing to a proinflammatory microenvironment that may be detrimental to long-term normal hematopoiesis within B-ALL bone marrow.

Background: Diagnostic testing for coronavirus disease (COVID)-19 is performed using nasopharyngeal swabs. This type of sampling is uncomfortable for the patient, dangerous for health workers, and its high demand has led to a global shortage of swabs. One of the alternative specimens is saliva. However, the optimal conditions for the test have not been established. Methods: Reverse transcription-polymerase chain reaction was used to detect the viral genome in saliva samples kept at room temperature, in the fridge or frozen for 2 days. In addition, the influence of brushing teeth and feeding on the detection of the virus in saliva was addressed. Finally, the efficiency of saliva in revealing the presence of the virus during the hospitalization period was determined in children. Results: The viral genome was consistently detected regardless of the storage conditions of saliva samples. Brushing teeth and feeding did not influence the sensitivity of the test. In hospitalized children, positive results were obtained only during the early days. Conclusions: These results support the idea of the use of saliva as an alternative specimen for diagnostic testing for COVID-19. The viral genome is stable and endures perturbations in the oral cavity. However, clearance of the virus from the mouth during the infection may limit the use of the test only to the early stages of the disease.

Due to their increasing rates of morbidity and mortality, childhood malignancies are considered a global health priority, with acute lymphoblastic leukemias (ALLs) showing the highest incidence worldwide. Control of malignant clone emergence and the subsequent normal‐leukemic hematopoietic cell out‐competition require antitumor monitoring mechanisms. Investigation of cancer surveillance innate cells may be critical to understand the mechanisms contributing in either disease progression or relapse, and to promote displacement of leukemic hematopoiesis by the normal counterpart. We report here that NK cell production is less and low hematopoietic progenitor numbers contribute to this defect. By investigating the expression of the activation molecule class I restricted T‐cell associated molecule (CRTAM) along the hematopoietic lineage differentiation pathway, we have identified lymphoid precursor populations coexpressing CD34, CD56/CD3/CD19, and CRTAM as the earliest developmental stage where activation may take place in specialized niches that display the ligand nectin‐like‐2. Of note, bone marrow (BM) from patients with ALL revealed high contents of preactivated CD56high NK cells expressing CRTAM and endowed with an exhaustion‐like phenotype and the functional capability of producing IL‐10 and TGF‐β in vitro. Our findings suggest, for the first time, that the tumor microenvironment in ALL directly contribute to exhaustion of NK cell functions by the CRTAM/Necl‐2 interaction, and that the potential regulatory role of exhausted‐like NK cells may favor malignant progression at the expense of anti‐tumor responses. Phenotypic and functional identity of this unique suppressor‐like NK cell population within the leukemic BM would be of special interest for the pathobiology of ALL and development of targeting strategies.