The effect of the expression of virulence-associated DEAD-box RNA helicase mRNA on the imbalance of Th1-Th2 cytokines in the CSF of patients with Cryptococcus neoformans meningitis

Abstract

Virulence-associated DEAD-box RNA helicase (VAD1) is an important factor regulating the virulence of Cryptococcus neoformans. We established a real-time quantitative polymerase chain reaction (PCR) assay to measure the expression of VAD1 mRNA in the cerebrospinal fluid (CSF) of C. neoformans meningitis (CNM) patients, and we also detected the levels of IFN-γ, IL-12 and IL-10 proteins in these CSF samples and controls. Patients with head injuries were selected as controls. We found that the expression of VAD1 mRNA was significantly higher in the acute phase than in the stable phase of CNM. The level of CSF IFN-γ and IL-10 in the acute phase (9.45 pg/ml ± 2.06 and 36.28 pg/ml ± 10.86, respectively) were different to that in the controls (11.89 pg/ml ± 1.75 and 7.33 pg/ml ± 1.68, respectively). The IFN-γ/IL-10 and IL-12/IL-10 ratios were significantly higher in controls than in the acute phase, but lower than in the stable phase. The expression of VAD1 mRNA is inversely related to IFN-γ and is correlated with IL-10 but not to IL-12. The Th2 response is dominant in the acute phase, whereas the immune response switches to a Th1 response in the stable phase. The expression of VAD1 mRNA is related to the imbalance of Th1-Th2 responses, which could be one of the mechanisms by which C. neoformans escapes the immune system.