The official MedZine Blog

Also this week MedZine brings you the latest medical news on various medical specialisms. In this editorial we report about a finding that changes the way we look at the development of the different blood cells.

Researchers at the Netherlands Cancer Institute and Utrecht University have used a smart trick to investigate how individual blood cells are derived from their precursors. Ton Schumacher and Rob de Boer have used a new quantitative version of 'cellular barcoding' to trace the fate of hundreds of hematopoietic progenitors and their progeny at the single-cell level.

Hematopoietic stem cells (HSCs) and their subsequent progenitors produce blood cells, but the precise nature and kinetics of this production is the topic of ongoing investigations. The general idea is that the lymphoid-primed multipotent progenitors (LMPP) give rise to the lymphoid and myeloid lineages. T cells and B cells are lymphoid, while granulocytes or monocytes are part of the myeloid lineage. The first general response of the immune system, called innate immune response, is mainly generated by myeloid cells. The secondary response that is tailor-made against the specific threat, the adaptive immune response, is mostly mediated by lymphoid cells. It was believed that dendritic cells, which form the link between the innate and adaptive immunity, could be generated in both lineages.

The results of this study published in Nature render these ideas obsolete. The dendritic cells seem to originate from a third lineage. Also a second dogma is challenged, namely the idea that the stem cells are multipotent, meaning that they can give rise to many different types of cells. However, the researcher found that most of these progenitors produce only one or a few types of blood cells. This shows that progenitors are programmed to produce certain types of blood cells and not all of them.

This leads to the suggestion of a ‘graded commitment’ model of hematopoiesis, where the decisions about what type of cells a progenitor can generate is made earlier than previously thought. This new model gives better insight into the development of blood cells and this knowledge can be used to improve our understanding of immunity and blood disorders, such as leukemia.

Source: Nature and Medicalfacts