Newsletter No. 235

More on SARS Telling the Complete Story of the SARS-coronavirus The Ch i n e se SARS M o l e c u l a r Ep i demi o l ogy Consortium, f o rmed during last year's SARS epidemic by researchers at the University and over 50 scientists from mainland China and the US to study the complete evolutionary h i s t o r y of the SARS - co r onav i r us, published their results on 30th January 2004 in Science. This research is the most extensive molecular epidemiological study of the SARS-coronavirus to date. A total of 63 SARS-coronavirus genomic sequences isolated from SARS patients infected at different time points were analysed in combination with detailed epidemiological data to map the precise landmarks of the evolution of the vims. The study found that the virus mutated continuously throughout the epidemic, most rapidly in the early part of the epidemic and at a third of the rate of the AIDS vims. It was also revealed that human SARS-coronavirus sequences differ from those isolated from civets by the absence of 29 units of genetic code in one region of the virus genome. A SARS-coronavirus sequence with a further absence of 386 units of genetic code in the same region of the virus genome was identified in two patients in May 2003. The same sequence was subsequently found in a group of 15 SARS patients whose infections were inter-related. This complete evolutionary map of the vims provides a blueprint for the prediction of the future sequence of events should SARS reemerge. The foresight would allow for better planning of public health control measures to prevent major outbreaks. The mutation rate of the virus is shown to be moderate in comparison with rapidly mutating viruses such as the HIV. This suggests that once successfully developed, vaccines are more likely to remain effective. The study also shows that in order to be effective, diagnostic tests have to be developed to target regions of the virus genome that are less likely to mutate. Genes May Hold Answer to Variations in SARS Susceptibility The importance of SARS infection is related to its characteristics of high infectivity and an unpredictable clinical course marked with significant fatalities. It has been observed that c l i n i c al severities among patients may vary from m i l d f eb r i le cond i t i ons to severe respiratory distress requiring assisted ventilation. Responses to infection by the SARS-coronavirus also appear to vary among individuals with apparently the same exposure. The patterns of human leucocyte antigen (HLA) genes, which influence the ability of T-lymphocytes to respond to a particular antigen or viral protein, are very important in most disease processes mediated by infections and autoimmunity. H LA genes control the expression of specific cell surface proteins. These proteins play important roles in the selection and maintenance of the appropriate spectrum of antigen-specific T-lymphocytes, and the activation of these T-lymphocytes during the initiation of immune responses. The HLA genes are highly variable among individuals and may contribute to the variation of immune responses to SARS infection. To assess the relationship of HLA genes with the risk of SARS infection, the Faculty of Medicine examined the blood samples of 90 SARS patients and studied the patterns of their HLA genes. The data indicate that individuals with one class of HLA protein have a much higher risk of getting SARS than the general population while those with another class have a much lower risk. These genetic data may explain individual variations in response to SARS infection. The findings have critical impact on understanding of the disease mechanisms of SARS and the design of SARS prevention programmes. A full report will be published in The Journal of Infectious Diseases. The results of the study were announced at a press conference on 15th January at the Postgraduate Education Centre of the Prince of Wales Hospital. Mainland SARS Expert Shares Ideas and Experience Prof. Zhong Nan-shan, famous Chinese expert i n t ho r ac ic medicine and respiratory disease, gave a public lecture entitled 'What We Have Learnt f r om SARS' in his capacity as Sir Run Run Shaw Distinguished Visiting Scholar of the college. The lecture was held on 20th January at the lecture theatre of Shaw College. Prof. Zhong Nan-shan is the president of Guangzhou Medical C o l l e ge and head o f t he G u a n g z h ou I n s t i t u t e o f Respiratory Disease. During last year's SARS outbreak in China, he headed an expert task force to gather data and trialled various strategies which eventually led to breakthrough treatments. The contribution of Prof. Zhong and his team has been affirmed by the World Health Organization. WE CARE Foundation Makes Graceful Exit The full balance of the WE CARE Foundation was transferred to the University's Faculty of Medicine on 31st January to support the research activities of the Centre for Emerging Infectious Diseases. With the completion of the fund transfer, the foundation's accounts are formally closed. As at 20th January, the foundation registered donations totalling some HK$2.27 million. After deducting expenses for specific causes, the unspent balance of HK$1.8 million was transferred to the CEID. WE CARE Foundation was set up by the Alumni Affairs Office of the University during the SARS outbreak in Hong Kong last March for relief of frontline health care workers at the Prince of Wales Hospital and other public hospitals. It was enthusiastically patronized by CUHK alumni and members of the public. Prof. Dennis Lo of the consortium speaking at a press conference about the SARS-coronavirus Prof. Margaret H.L. Ng from the Department of Anatomical and Cellular Pathology explaining the relationship between HLA genes and the SARS- coronavirus Prof. Zhong Nan-shan Upcoming Anniversary Celebration University Presidents' Global Forum 2004 The University Presidents' Global Forum 2004 'Universities in the 21st Century' will be held from 28th to 30th March 2004 at T.Y. Wong Hail and Cho Yiu Conference Hall on CUHK campus. It will be conducted in putonghua and English with simultaneous interpretation from English to putonghua and vice versa. Please visit http://www.cuhk.edu.hk/40thanniversary f or updates. 1 No. 235 19th February 2004