Trachoma, which is caused by ocular infection with Chlamydia trachomatis, remains the leading infectious cause of blindness and in 2002 was responsible for 3.6% of total global blindness. In a paper published in PLoS Medicine, Martin Holland and colleagues from the London School of Hygiene and Tropical Medicine have studied the human immune response to this infection in a population where trachoma is very common.
The researchers studied 345 children in the Gambia, who could be divided into four groups based on infection with C. trachomatis and clinical signs. Some children--particularly the older ones--were uninfected and had no clinical signs. Others were infected but showed no clinical signs--these children were incubating the bacteria. Some were infected and had clinical disease; these children had the highest bacterial loads. Finally, children recovering from an infection carried no bacteria but still had some clinical signs. The researchers detected different types of immune response in each of these groups.
Children incubating the bacteria had a strong pro-inflammatory response--their immune systems were trying to fight off infection. The pro-inflammatory response was even stronger in the infected children with clinical signs, but the regulatory response was also increased, presumably to limit inflammation. In children in the recovery phase, only regulatory immune cells, which were making mRNA from a gene called FOXP3, remained active.
These results suggest that the interaction between the infection and the clinical disease process is complex and that regulatory immune cells are important in limiting the inflammatory response to this infection. This information about immune responses at different stages of infection with C. trachomatis may help in the design of vaccines to prevent this infection.
Citation: Faal N, Bailey RL, Jeffries D, Joof H, Sarr I, et al. (2006) Conjunctival FOXP3 expression in trachoma: Do regulatory T cells have a role in human ocular Chlamydia trachomatis infection? PLoS Med 3(8): e266.
PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.doi.org/10.1371/journal.pmed.0030266
PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-03-08-holland.pdf
Related image for press use: http://www.plos.org/press/plme-03-08-holland.jpg
· Caption: Immunology in action: follicular trachoma in a Gambian child
CONTACT:
Martin Holland
London School of Hygiene and Tropical Medicine
Infectious and Tropical Diseases
Keppel Street
PO Box 273
London WC1E 7HT United Kingdom
+44 20 7927 2817
Martin.Holland@lshtm.ac.uk
Creating and validating an algorithm to measure AIDS mortality in the adult population using verbal autopsy
Based on verbal autopsy from patients in rural Zimbabwe, 69% of deaths were correctly classified as AIDS/non-AIDS. The authors say the method can be used in demographic surveillance on AIDS deaths.
Citation: Lopman BA, Barnabas RV, Boerma JT, Chawira G, Gaitskell K, et al. (2006) Creating and validating an algorithm to measure AIDS mortality in the adult population using verbal autopsy. PLoS Med 3(8): e312.
PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.doi.org/10.1371/journal.pmed.0030312
PRESS-ONLY PREVIEW OF THE ARTICLE: http://www.plos.org/press/plme-03-08-lopman.pdf
CONTACT:
Ben Lopman
Imperial College London
Department of Infectious Disease Epidemiology
St Mary's Campus
London W2 1PG United Kingdom
+44 207 594 3631
b.lopman@imperial.ac.uk
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PLoS Medicine is an open access, freely available international medical journal. It publishes original research that enhances our understanding of human health and disease, together with commentary and analysis of important global health issues. For more information, visit http://www.plosmedicine.org
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