BALTIMORE--A small study of HIV-infected patients conducted by researchers at the National Institute of Allergy and Infectious Disease (NIAID) shows that inoculation with a common vaccine can temporarily increase the amount of HIV that is circulating in the bloodstream.
All 13 of the HIV-positive subjects who received a tetanus shot as part of the experiment showed increased viremia after their inoculation, NIAID director Anthony S. Fauci said at the American Association for the Advancement of Science (AAAS) meeting.
He cautioned, however, that the finding is too preliminary to make any recommendations regarding whether to limit vaccinations for people infected with HIV. However, based on his experience treating AIDS patients, Dr. Fauci said he would "rather have a patient with a small blip in HIV levels from a needed inoculation than with a full-blown infectious disease."
A long-standing question among AIDS researchers is whether persistent infections or co-infections can increase the risk of HIV infection and/or hasten the time to development of full-blown AIDS. Dr. Fauci cited as an example the case of a person whose HIV blood levels rose after he developed tuberculosis and dropped again after he responded to treatment for the disease.
The NIAID vaccination experiment grew out of a study of the role of cyto-kines in immunity and their influence on HIV. Among HIV-infected individuals, there occurs "a hyperexpression of cytokines" because the virus releases factors that can stimulate cytokine production, Dr. Fauci said.
Different cytokines can upregulate or downregulate the AIDS virus. Most, however, act to increase the burden of HIV in the blood, while immune system CD8 cells suppress HIV expression.
"Going on in the body virtually every minute is this tug-of-war between the upregulating and downregulating factors," he said.