Center for Tropical and Emerging Global Diseases and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens,1 Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia,3 Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand,2 Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania,4 Vector Biology and Control Research Center, Kenya Medical Research Institute,5 New Nyanza Provincial General Hospital, Kisumu, Kenya,6 Roll Back Malaria Program, World Health Organization, Geneva, Switzerland7
Received 7 May 2004/ Returned for modification 24 June 2004/ Accepted 6 September 2004
Pregnant women are at an increased risk for malarial infection. Plasmodium falciparum accumulates in the placenta and is associated with dysregulated immune function and poor birth outcomes. Malarial pigment (hemozoin) also accumulates in the placenta and may modulate local immune function. In this study, the impact of hemozoin on cytokine production by intervillous blood mononuclear cells from malaria-infected placentas was investigated. There was a dose-dependent, suppressive effect of hemozoin on production of gamma interferon (IFN-
), with less of an effect on tumor necrosis factor alpha (TNF-
) and interleukin-10, in human immunodeficiency virus-seronegative (HIV) women. In contrast, IFN-
and TNF-
production tended to increase in HIV-seropositive women with increasing hemozoin levels. Production patterns of cytokines, especially IFN-
in HIV women, followed different trends as a function of parasite density and hemozoin level. The findings suggest that the influences of hemozoin accumulation and high-density parasitemia on placental cytokine production are not equivalent and may involve different mechanisms, all of which may operate differently in the context of HIV infection. Cytokine production dysregulated by accumulation of hemozoin or high-density parasitemia may induce pathology and impair protective immunity in HIV-infected and -uninfected women.
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
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| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
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