Protective host defense against disseminated candidiasis is impaired in mice expressing human interleukin-37.

The effect of the anti-inflammatory cytokine interleukin-37 (IL-37) on host defense against Candida infections remains unknown. We assessed the role of IL-37 in a murine model of disseminated candidiasis using mice transgenic for human IL-37 (hIL-37Tg). Upon exposure to Candida albicans pseudohyphae, macrophages from hIL-37Tg mice release 39% less TNFα compared to cells from wild-type (WT) mice (p = 0.01). In vivo, hIL-37Tg mice displayed a decreased capacity to recruit neutrophils to the site of infection. These defects were associated with increased mortality and organ fungal growth in hIL-37Tg compared to WT mice. We conclude that IL-37 interferes with the innate protective anti-Candida host response by reducing the production of proinflammatory cytokines and suppressing neutrophil recruitment in response to Candida, resulting in an increased susceptibility to disseminated candidiasis.