However, until now, it is not clear whether these stimuli and these myeloid cells are directly involved in IL-10 production during the first 48hpi with S. pneumoniae. In Klebsiella pneumoniae-induced pneumonia, macrophages, monocytic myeloid-derived suppressor cells (M-MDSCs) and neutrophils have been described as the main contributors to IL-10 production during bacterial pneumonia (19, 26, 27). This evidence concerns the gene IL10 and pneumonia.