Salivary histatin-5 and oral fungal colonisation in HIV+ individuals

Abstract

The oral cavity is a primary target for opportunistic infections, particularly oral candidiasis caused by the opportunistic pathogen Candida albicans. HIV+ individuals constitute a population highly susceptible to oral candidiasis possibly due to a change in the environment of the oral cavity as the result of salivary gland dysfunction. Histatins are a family of salivary antimicrobial peptides which under normal circumstances have a protective function on the oral mucosa. This study aimed to compare salivary histatin concentrations and oral fungal colonisation in an HIV+ and HIV- control populations. Oral samples for fungal cultures and parotid saliva were collected from all subjects. Fungal identification was determined using standard mycological procedures. In order to determine salivary histatin levels a semi-quantitative ELISA was designed using a specific polyclonal antibody and extensive statistical analysis was performed. Forty-seven percent of HIV+ and 17% of control subjects had positive fungal cultures. Mean histatin levels were 7.32 microg ml(-1) for the HIV+ group and 9.17 microg ml(-1) for control group (P = 0.003). The data from this study demonstrate that the level of fungal colonisation is significantly higher in HIV+ individuals whereas histatin-5 concentrations are significantly lower, likely contributing to the enhanced predisposition of this population to oral candidiasis.