Th1/Th2 cytokine expression in saliva of HIV-positive and HIV-negative individuals: A pilot study in HIV-positive individuals with oropharyngeal candidiasis

Current data suggest that T-helper (Th)2-type cytokine responses are often associated with progression to AIDS in HIV-positive individuals. Similarly, Th2-type cytokines are associated with susceptibility to mucosal candidiasis, of which oropharyngeal candidiasis (OPC) is one of the most common opportunistic infections in HIV-positive individuals. Although little information is available on host defense mechanisms at the level of the oral mucosa, recent studies suggest that local cell-mediated immunity (CMI) is equally or more important than that in the periphery for host defense against mucosal Candida albicans infections. This study investigated the potential presence of oral-associated CMI through the expression of Th1/Th2-type cytokines in saliva of immunocompetent and immunocompromised individuals with and without OPC. Results showed a constitutive mixed Th1/Th2 cytokine expression (Th0) in whole saliva of healthy HIV-negative individuals. In contrast, HIV-positive individuals had a dominant Th2-type salivary cytokine profile (interleukin-4 [IL-4], IL-10) (IL-2, interferon-gamma [IFN-gamma], IL-12) that seemingly resulted from a lack of Th1-type cytokines rather than enhanced Th2-type cytokines. Moreover, pilot analyses of those with OPC showed evidence for a more profound salivary Th2-type profile. Both HIV-positive and HIV-negative patients, irrespective of CD4 counts, had some level of positive in vitro systemic lymphocyte proliferative responses to C albicans antigens, These results suggest that the Th1/Th2 cytokine dichotomy in HIV disease is detectable in situ in oral secretions and may be a useful indicator of oral-associated CMI to better understand resistance/susceptibility of HIV-positive individuals to oral opportunistic infections, including OPC.