The Impact of Helminths on HIV, Measles, and Tetanus-specific IgG Antibody Responses among HIV Co-infected Adults in Kenya

Thesis (Ph.D.)--University of Washington, 2013In Africa, helminth and HIV infection is highly prevalent, making co-infection with helminths and HIV likely common. Both infections impact the host immune response through immune suppression and dysregulation, which also may have implications for vaccine efficacy and efforts to decrease vaccine preventable deaths. We sought to determine the impact of helminth infection on humoral immune responses to HIV and to previously administered measles and tetanus vaccines. We developed a method to evaluate HIV-specific antibody responses using protein microarray and principal components analysis, and identified distinct patterns of HIV-specific antibody responses that correlate with concurrent viral load and subsequent change in CD4 count. Within two randomized trials examining the effect of deworming on HIV disease progression, we conducted nested serologic studies to examine the impact of helminth infection (n=100) and deworming (n=35) on specific antibody responses. The prevalence of HIV specific antibody responses was similar between individuals with any helminth infection compared to helminth uninfected individuals. However, those with schistosomiasis infection had significantly lower HIV specific antibody responses compared to helminth uninfected adults. The prevalence of measles and tetanus antibody responses were similar between helminth infected and uninfected individuals. Comparing dewormed to placebo treated Ascaris and HIV co-infected adults, changes in measles and tetanus antibody responses over 3 months were comparable between treatment groups. Though helminths did not alter antibody responses to previously administered measles and tetanus vaccines, antibody responses to concurrent HIV infection may be diminished in individuals who are co-infected with some helminth species