Thus, studies of inborn errors of GM-CSF and their autoimmune phenocopies suggest that GM-CSF is a crucial cytokine for immunity to Nocardia and Cryptococcus spp., particularly in the lungs and CNS, and that patients with idiopathic isolated cryptococcosis or nocardiosis may suffer from inborn errors of the GM-CSF pathway. Here, CSF2 is linked to nocardiosis.