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Impact of helminth infection on the clinical presentation 1 of pulmonary tuberculosis
Gondar College of Medical and Health Sciences, Gondar University, Gondar, Ethiopia; Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
School of Medical Laboratory Sciences, Medical Faculty, Addis Ababa University, Addis Ababa.
Gondar College of Medical and Health Sciences, Gondar University, Gondar, Ethiopia.
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2013 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Background: The effects of helminth infection on chronic infectious diseases such as HIV and tuberculosis (TB) merit further characterization. Thus, we assessed the baseline clinical characteristics of helminth infection in patients with active TB in a high endemic area.

Methodology: Consecutive, newly diagnosed TB patients were recruited from three health institutions in the north Gondar administrative zone, Ethiopia. Structured questionnaires were used to collect socio-demographic and clinical characteristics. Additionally, the TB score, mid upper arm circumference, body mass index (BMI), BCG vaccination status, stool and sputum microscopy as well as HIV serology and CD4+T cells counts were evaluated.

Results: A total of 377 pulmonary TB patients were included in the study. The helminth co infection rate was 33% (123/377) and the most prevalent parasite was Ascaris lumbricoides (53%, 65/123). The HIV co-infection rate was 29% (110/377). Seventy percent (77/110) of the HIV co-infected patients were on anti- retroviral therapy at the time of TB diagnosis. Helminth infection was more prevalent in HIV-negative TB patients compared to HIV-positive TB patients (p=0.025). Smoking and walking bare foot were independently associated to helminth infection in TB patients after adjusting for the influence of HIV. Other than increased eosinophilia, no other significant differences were observed between helminth positive and helminth negative TB patients in the clinical presentation including the TB score, CD4+T-cells, BMI or bacterial load.

Conclusion: The clinical presentation of active pulmonary tuberculosis was not affected by helminth infection. Helminth infection was less frequent among HIV-positive TB patients and this finding merits further investigation.

Place, publisher, year, edition, pages
Keyword [en]
Tuberculosis, HIV, helminth, TB score, CD4, Ethiopia
National Category
Medical and Health Sciences
URN: urn:nbn:se:liu:diva-91825OAI: diva2:619194
Available from: 2013-05-02 Created: 2013-05-02 Last updated: 2013-05-02Bibliographically approved
In thesis
1. The impact of helminth infection in patients with active tuberculosis
Open this publication in new window or tab >>The impact of helminth infection in patients with active tuberculosis
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The geographic distribution of helminth infection and tuberculosis (TB) overlap substantially. Experimental animal models and limited data from humans have shown that intestinal helminths could subvert the host immune response towards a T-helper 2 (Th2)-type immune response and an increased regulatory T-cell activity (Tregs). This in turn affects the host's ability to mount an effective Th1 immune-mediated protection against Mycobacterium tuberculosis. However, evidence for this hypothesis in the human setting from helminth infected TB patients is limited. This thesis primarily focuses on the immunological and clinical impact of helminth infection on pulmonary TB. The kinetics of the Quantiferon-Gold (QFN) assay, which measures IFN-³ response to TB-specific antigens in whole blood was assessed and showed a modest decline during TB treatment to the level observed for healthy blood donors. We further assessed another clinical monitoring tool, the-TB-score, composed of clinical signs and symptoms of TB, and found an early decline two weeks after initiation of TB- treatment where a failure of decline correlated with increased mortality. Overall, the helminth co-infection rate was significantly higher in TB patients compared to healthy controls. Helminth co-infection was associated to a significantly higher rate of eosinophilia and IgE-levels in healthy controls and patients with tuberculosis. During the first weeks of anti-TB treatment, a marked decrease in the rate of helminth infection was observed in HIV co-infected compared to HIV-negative TB patients. However, helminth co-infection was more common in HIV negative than HIV positive TB patients. There was no detectable impact of helminth infection on the clinical presentation of pulmonary tuberculosis. At baseline, helminth co-infected TB patients showed an increased frequency of Tregs compared to helminth negative TB patients and healthy controls. This was accompanied by an increased rate of PPD stimulated IL-5 and spontaneous production of IL-10 by peripheral blood mononuclear cells among helminth co-infected TB patients. A placebo controlled randomized trial was conducted in order to test the hypothesis that albendazole treatment of helminth positive TB patients may improve the clinical response of TB by reducing the immunmodulatory effect of helminthes on TB immunity. A total of 140 helminth co-infected TB patients were randomized to albendazole (400 mg per os for three consecutive days) or placebo. No significant difference was observed between the albendazole and placebo group in terms of the primary outcome (TB score change between baseline and week 8). Among the secondary outcomes, a significant decline of peripheral eosinophil cells was observed in the albendazole treated group, but no effect on other outcome variables (changes in chest x-ray findings, IgE level and sputum smear conversion). Regarding the immunological assessment no significant difference was observed for changes in Tregs, and PPD-induced production of IFN- ³ or IL-5 although a non-significant trend of a decrease in IL-10 expressing PBMCs were observed in the albendazole group. Taken together, the burden of helminth infection was higher in TB patients than in a healthy control group. Helminth co-infection during pulmonary TB in the human setting induces an immune response characterized by increased IgE production, eosinophilia as well as increased levels of Tregs and spontaneous IL-10 production. Thus, the immunological impact of helminth infection on the outcome and risk for developing TB merits further investigation.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2013. 84 p.
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1361
National Category
Medical and Health Sciences
urn:nbn:se:liu:diva-91833 (URN)978-91-7519-653-4 (print) (ISBN)
Public defence
2013-06-05, Berzeliussalen, Hälsouniversitetet, Campus US, Linköpings universitet, Linköping, 13:00 (English)
Available from: 2013-05-02 Created: 2013-05-02 Last updated: 2013-05-22Bibliographically approved

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