The Alternaria mycotoxins alternariol (AOH) and alternariol monomethyl ether (AME) have been shown to possess genotoxic and cytotoxic properties. In this study, the ability of AOH and AME to modulate innate immunity in the human bronchial epithelial cell line (BEAS-2B) and mouse macrophage cell line (RAW264.7) were investigated. During these studies, it was discovered that AOH and to a lesser extent AME potently suppressed lipopolysaccharide (LPS)-induced innate immune responses in a dose-dependent manner. Treatment of BEAS-2B cells with AOH resulted in morphological changes including a detached pattern of growth as well as elongated arms. AOH/AME-related immune suppression and morphological changes were linked to the ability of these mycotoxins to cause cell cycle arrest at the G2/M phase. This model was also used to investigate the AOH/AME mechanism of immune suppression in relation to aryl hydrocarbon receptor (AhR). AhR was not found to be important for the immunosuppressive properties of AOH/AME, but appeared important for the low levels of cell death observed in BEAS-2B cells.

Alternaria alternata is a saprophyte and is also known to cause many opportunistic infections in humans. Alternaria infections are important factors of morbidity and mortality in im-mune-compromised and solid organ transplant (SOT). Sensitivity to the airborne fungus Alter-naria alternata is also believed to be a common cause of allergic asthma. Therapies are limited by the lack of knowledge about the role of individual fungal gene products and symptoms in im-mune-compromised and transplant patients. This review summarizes the published case studies on Alternaria alternata infections in transplant patients.