Stem Cells Dev. 2021 Sep 13. doi: 10.1089/scd.2021.0211. Online ahead of print.
Adult stem cells are characterized not only by their regenerative and immunomodulatory capacity but also by their therapeutic potential in various pathologies that include hematological malignancies, cancer, and autoimmune and inflammatory diseases, among others. However, these cells seem to play a paradoxical role during the development of the immune response in some infectious diseases. As an example, Candida albicans can induce the proliferation and differentiation of hematopoietic stem cells and their progenitors, a process known as emergency hematopoiesis. Moreover, Aspergillus fumigatus and C. albicans, once recognized by mesenchymal stromal cells (MSCs), can induce an anti-inflammatory or pro-inflammatory profile, respectively, and, in turn, these cells can inhibit the growth of these fungal pathogens. Additionally, the transplantation of MSCs, in an experimental pulmonary model of paracoccidioidomycosis, has been shown to exacerbate the inflammatory response. More recently, in vitro studies have shown that MSCs recognize Paracoccidioides brasiliensis through a mechanism mediated by TLR2, TLR4, and Dectin-1, which, in turn, induces a pro-inflammatory profile. This review describes the main mechanisms and immunomodulatory properties of hematopoietic stem cells and mesenchymal stromal cells during infections caused by some medically important fungal pathogens described so far in literature.