Malaria causes 300-500 million clinical cases and 1-3 million deaths per year, the majority of which occur in young African children. Ingestion of hemozoin by peripheral blood mononuclear cells (PBMC) initiates the cytokine-mediated cascade of immune dysregulation in malaria. Innate immunity plays a critical role in protective responses against infection, which are determined by an appropriate balance between pro- and anti-inflammatory mediators. Pro-inflammatory mediators (TNF-α, IL-12, IFN-γ) that control parasitemia also contribute to pathology. Over-production of immunomodulatory cytokines (TGF-β, IL-10) suppresses the protective pro-inflammatory immune response. The effects of hemozoin on hematological outcomes and inflammatory mediator production in children with malarial anemia and the temporal kinetics of hemozoin-induced cytokine dysregulation in cultured PBMC were investigated in this study. Hematological analyses of healthy control (HC), uncomplicated malaria (UM), mild malarial anemia (MlMA), moderate malarial anemia (MdMA), and severe malarial anemia (SMA) groups revealed that age, temperature, and all erythrocyte, leukocyte, and platelet indices were significantly different between clinical categories. Neither parasitemia nor the prevalence of high density parasitemia (HDP) differed significantly between clinical groups. Stratification of study participants according to proportion of pigment-containing monocytes (PCM) demonstrated that parasitemia, HDP, temperature, and most leukocyte, erythrocyte, and platelet indices were significantly different between 0%, ≤ 10%, and > 10% PCM categories. The > 10% PCM category contained children with the lowest hemoglobin, hematocrit, and erythrocyte counts and the greatest proportion of children with SMA. Plasma IFN-α, IL-4, IL-6, IL-10, and IL-12p40/p70 levels differed significantly between clinical categories but not between UM and SMA groups. Plasma IFN-α, IFN-γ, TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-10, and IL-12p40/p70 were not significantly associated with % PCM. β-hematin-induced IL-1β, IL-2, IL-6, IL-12p35, IL-12p40, IL-18, IFN-α, IFN-γ, TNF-α, LT-α, NOS-2A, COX-1, COX-2, IL-4, IL-10, and TGF-β expression in cultured PBMC revealed a pro-inflammatory response that varied in magnitude among individuals. Importantly, innate inflammatory mediators modulate the adaptive immune response to Plasmodium parasites. Of public health significance, a better understanding of the molecular mechanisms governing these responses will facilitate the development of more immunogenic vaccines, through inclusion of cytokines or other compounds that activate the innate immune system.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-11062006-220938 |
| Date | 02 February 2007 |
| Creators | Kristoff, Jan |
| Contributors | Douglas J. Perkins, Jeremy J. Martinson, Karen A. Norris |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-11062006-220938/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.0018 seconds