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T-cell responses are associated with survival in acute Melioidosis patients
- Source :
- PLoS Neglected Tropical Diseases, Vol 9, Iss 10, p e0004152 (2015), PLoS Neglected Tropical Diseases
- Publication Year :
- 2016
- Publisher :
- Public Library of Science, 2016.
-
Abstract
- Background Melioidosis is an increasingly recognised cause of sepsis and death across South East Asia and Northern Australia, caused by the bacterium Burkholderia pseudomallei. Risk factors include diabetes, alcoholism and renal disease, and a vaccine targeting at-risk populations is urgently required. A better understanding of the protective immune response in naturally infected patients is essential for vaccine design. Methods We conducted a longitudinal clinical and immunological study of 200 patients with melioidosis on admission, 12 weeks (n = 113) and 52 weeks (n = 65) later. Responses to whole killed B. pseudomallei were measured in peripheral blood mononuclear cells (PBMC) by interferon-gamma (IFN-γ) ELIspot assay and flow cytometry and compared to those of control subjects in the region with diabetes (n = 45) and without diabetes (n = 43). Results We demonstrated strong CD4+ and CD8+ responses to B. pseudomallei during acute disease, 12 weeks and 52 weeks later. 28-day mortality was 26% for melioidosis patients, and B. pseudomallei-specific cellular responses in fatal cases (mean 98 IFN-γ cells per million PBMC) were significantly lower than those in the survivors (mean 142 IFN-γ cells per million PBMC) in a multivariable logistic regression model (P = 0.01). A J-shaped curve association between circulating neutrophil count and mortality was seen with an optimal count of 4000 to 8000 neutrophils/μl. Melioidosis patients with known diabetes had poor diabetic control (median glycated haemoglobin HbA1c 10.2%, interquartile range 9.2–13.1) and showed a stunted B. pseudomallei-specific cellular response during acute illness compared to those without diabetes. Conclusions The results demonstrate the role of both CD4+ and CD8+ T-cells in protection against melioidosis, and an interaction between diabetes and cellular responses. This supports development of vaccine strategies that induce strong T-cell responses for the control of intracellular pathogens such as B. pseudomallei.<br />Author Summary Melioidosis is a key cause of death in South East Asia and Northern Australia. It is caused by the soil-dwelling bacteria Burkholderia pseudomallei, and presents as a range of clinical illnesses including pneumonia and bloodstream infections. About two-thirds of patients with melioidosis in Thailand have diabetes, but the immune responses associated with death and diabetes are unknown. This study examined the relationship between immune responses to the bacteria and death by studying the bacteria-specific lymphocyte responses in 200 patients admitted to hospital with acute melioidosis and following the patients for up to one year where possible. 26% of patients died within 28 days despite receiving antibiotics and supportive care. We showed people with melioidosis make bacteria-specific lymphocyte responses, with lower levels seen in fatal cases compared to survivors. People with diabetes make lower responses than people without diabetes, and higher levels of circulating neutrophils on admission to hospital were associated with lower lymphocyte responses both during illness and three months later in survivors. This highlighting of lymphocyte responses to melioidosis is important for the design of vaccines to target at risk groups.
- Subjects :
- Adult
CD4-Positive T-Lymphocytes
Male
Enzyme-Linked Immunospot Assay
Burkholderia pseudomallei
Melioidosis
lcsh:Arctic medicine. Tropical medicine
lcsh:RC955-962
030231 tropical medicine
CD8-Positive T-Lymphocytes
Peripheral blood mononuclear cell
Diabetes Complications
Sepsis
Interferon-gamma
Young Adult
03 medical and health sciences
0302 clinical medicine
Immune system
Diabetes mellitus
Humans
Medicine
Longitudinal Studies
Asia, Southeastern
Aged
030304 developmental biology
Aged, 80 and over
0303 health sciences
biology
business.industry
ELISPOT
lcsh:Public aspects of medicine
Australia
Public Health, Environmental and Occupational Health
lcsh:RA1-1270
Middle Aged
Flow Cytometry
medicine.disease
biology.organism_classification
Survival Analysis
3. Good health
Blood
Infectious Diseases
Immunology
Leukocytes, Mononuclear
Absolute neutrophil count
business
Research Article
Subjects
Details
- ISSN :
- 19352727
- Database :
- OpenAIRE
- Journal :
- PLoS Neglected Tropical Diseases, Vol 9, Iss 10, p e0004152 (2015), PLoS Neglected Tropical Diseases
- Accession number :
- edsair.doi.dedup.....329cbff7a53f46d323afb25af87842d1