Plasma and salivary IgG subclasses in HIV type 1 infection: evidence of both transudation and local synthesis of IgG in parotid saliva.

In this study we measured the levels of plasma and salivary IgG subclasses in 81 HIV-1-infected individuals and 30 uninfected controls. Salivary IgG1 was increased in HIV-1-infected patients, while salivary IgG2 and IgG4 were decreased. Patients with high levels of plasma anti-HIV-1 IgG antibodies presented a higher CD4+ cell count and lower viral load. High levels of anti-HIV-1 IgG antibodies in plasma were also associated with high levels of anti-HIV-1 IgG antibodies in parotid saliva. In comparing the HIV-1 recognition patterns of salivary IgG with plasma IgG, we determined that plasma and salivary IgG antibodies had similarities as well as differences in their reactivity to HIV-1 antigens. The present study demonstrates that HIV-1 infection affects both plasma and salivary IgG and provides evidence that the origin of HIV-1-specific IgG antibodies in parotid saliva is primarily transudated from plasma; however, some local synthesis of IgG in parotid saliva also occurs.