Th2 skewing in patients with disseminated coccidioidomycosis

BACKGROUND: Disseminated coccidioidomycosis (DCM) is an often fatal and otherwise intractable condition requiring lifelong antifungal treatment. We have previously shown that a deranged polarization of CD4+ T cells toward a Th2 phenotype can exist in the context of DCM. Here we studied a large population of subjects to determine the frequency of abnormal Th2 skewing of CD4+ T cells in patients with coccidioidomycosis and to identify underlying genetic mechanisms supporting this phenotype. METHODS: We collected peripheral blood mononuclear cells from 204 patients with coccidioidomycosis, including 96 patients with disseminated disease. We measured immune phenotypes and cytokine production by CD4+ T cells from patients and healthy controls, and comparisons between groups were made based on disease severity and demographics. Whole genome sequencing was conducted on 180 individuals who also had cytokine profiling. RESULTS: We found that ~25% of DCM patients had a CD4+ T-cell compartment that was abnormally skewed toward a Th2 phenotype, and Th2 skewing was highly correlated with male sex. Co-culture of T cells with the IL4R/IL13R-blocking antibody dupilumab reduced Th2 skewing. Sequencing revealed rare variants in genes involved in the IL-12-IFN-γ axis in several Th2-skewed patients, and we validated one such variant in IFNGR1 as hypomorphic. CONCLUSION: Patients with DCM, especially males, should be screened for Th2 skewing of CD4+ T cells. Patients with Th2 skewing should be additionally screened for genetic defects in the IL-12-IFN-γ axis. Our findings give a mechanistic rationale for blockade of IL4R in Th2-skewed patients with refractory coccidioidomycosis.