Results of the researchers' study, published in the Journal of Experimental Medicine, show that by simply delaying when an infant suffers from respiratory syncytial virus (RSV) - the major cause of common cold in adults - may make the difference.
RSV will infect most children during the first year of life and can keep re-infecting, as it is able to get around the immune system. For some infants RSV leads to bronchiolitis, one of the major causes of infant hospitalisation in the Western world. And around 40 percent of infants who experience bronchiolitis as a result of RSV infection are subsequently affected by recurring wheeze and asthma in childhood.
Professor Peter Openshaw from Imperial College London at St Mary's Hospital says: "Although there is still no way to prevent babies being infected by RSV, keeping people with colds away from young babies could reduce the chances of infection. Merely delaying infection beyond the first six months could have a significant impact on the later health of a child."
In tests carried out in mice, researchers were able to show that delaying RSV infection can have a significant effect on cytokine production and lung pathology during subsequent re-infection.
Dr Fiona Culley from Imperial College London at St Mary's Hospital says: "What is interesting from the point of view of our understanding of immunology, is just how differently the immune system deals with RSV infection at different ages, and the long-term consequences that neonatal infection can have on immune responses and pathology later in life."
Primary RSV infection in newborn mice followed the same viral kinetics as in adults but was associated with reduced and delayed IFN-y responses. For the study, mice were infected at one day, or one, four or eight weeks, and re-infected at twelve weeks (adulthood). Neonatal priming produced more severe weight loss and increased inflammatory cell recruitment to the lungs (including T helper 2 cells, neutrophils and eosinophils) during re-infection whereas delayed priming led to enhanced interferon gamma production and less severe disease during re-infection.
The research was made possible through grants from the Wellcome Trust.
Notes to editors
1. Journal of Experimental Medicine, Volume 196, Number 10, November 18, 2002.
2. Consistently rated in the top three UK university institutions, Imperial College London is a world leading science-based university whose reputation for excellence in teaching and research attracts students (10,000) and staff (5,000) of the highest international quality. Innovative research at the College explores the interface between science, medicine, engineering and management and delivers practical solutions that enhance the quality of life and the environment - underpinned by a dynamic enterprise culture. Website: www.ic.ac.uk.
3. On 14 October 2002 Imperial College London and University College London began to explore the possibility of merger to create a new, globally competitive university committed to teaching, scholarship and research. Together the two university institutions would form Britain's biggest university with a combined annual turnover in 2001 of £802 million, research income of £407 million, 3200 academic staff and over 28,000 students. A decision on whether to proceed with merger is expected in December 2002.
4. St Mary's NHS Trust was named a three star NHS Trust in July, the highest possible Government performance rating. A teaching hospital, it has a comprehensive range of acute and specialist services delivered from two main sites: St Mary's Hospital in Paddington, and The Western Eye Hospital in Marylebone Road. It covers a 13 mile area including Westminster, Kensington & Chelsea, and South Brent, and incorporating more than 349,000 residents and employing over 3,000 staff.