CSF1 and cryptococcosis: The exact role of M-CSF in protective anticryptococcal immune responses in the context of HIV coinfection is unclear, although extensive data demonstrating the importance of effective alveolar macrophage responses in controlling early cryptococcal infection [6], and the key role of circulating and tissue macrophage/microglial responses during later disseminated disease [39, 40], provide a plausible basis for why variations in CSF1 gene expression might impact susceptibility to cryptococcal disease.