PMC:7108609 / 22614-26289
Annnotations
{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/7108609","sourcedb":"PMC","sourceid":"7108609","source_url":"https://www.ncbi.nlm.nih.gov/pmc/7108609","text":"Since the epidemiology of SARS has been well documented (Anderson et al. 2004; He and Chinese 2004), it was possible to develop a model of the virus transmission that takes into account the effect of the ABO polymorphism. Critical transmission parameters were deduced from those of the global SARS outbreak and from those of the Hong Kong hospital outbreak where the ABO effect was observed. The model considers that no prophylatic measures were taken; although this is clearly unrealistic, it allows us to fully appreciate the impact of the blood group polymorphism itself. Of note, the expression of ABH antigens in epithelial cells where SARS-CoV replicates is also controlled by polymorphisms of the FUT2 gene. Thus, individuals with two FUT2 null alleles, the so-called nonsecretors, are unable to synthesize H antigen and hence A or B antigens in these cells (Marionneau et al. 2001). For simplicity, the model did not consider such individuals since with regard to the virus transmission, they would behave as O blood group donors. Including them in the analysis is therefore similar to slightly increase the pool of O individuals. Since anti-A and anti-B titer interindividual variability is quite high, and since we observed that plasmas from O blood group individuals with low anti-A titers were not inhibitory in the cell adhesion assay (not shown), we considered transmission parameters allowing for a moderate ABO effect only. In this case, virus transmission in incompatible ABO situations remains possible but with a lower probability of occurrence than in compatible situations. That is certainly more realistic than the case of the strong ABO effect where ABO incompatibility completely impairs virus transmission. The latter case was analyzed in order to evaluate the maximal potential of the ABO polymorphism. The model indicated that both in the presence of a moderate or a strong group effect, virus transmission was decreased, supporting the hypothesis that natural anti-A and -B antibodies can contribute to protect against selected viral diseases at the population level. Less intuitively, the model shows that the main effect of the natural anti-histo-blood group antibodies is to delay and slow down the epidemic. In the case of a full protection (strong effect), the delay between the occurrence of the first cases and the full development of the outbreak can be very large. It is linked to the frequency of O individuals in the population, but remains very significant even in a population with an unusually low blood group O frequency such as the Aïnous of Japan. This delay, already clearly visible when taking into account a moderate ABO effect only, might have had an adaptative value, in past epidemics of other viruses with transmission characteristics similar to those of SARS, since it allows for modifications of behavior limiting the spread of epidemics. This could have contributed to the maintenance of the ABO polymorphism throughout human evolution and history. Mean natural anti-A or -B titers tend to decrease over the years in developed countries, possibly due to improved hygiene (Dr. A. Blancher, personal communication). It is thus possible that in the past their protective effect was higher than in most contemporary populations. It could thus be of interest to raise the levels of anti-A or -B in all populations so as to slow and limit the spread of some emergent pathogens. This could prove a valuable prevention strategy against SARS but also against other coronaviruses which are responsible for a significant proportion of common colds and can contribute to more severe respiratory tract infections (van der Hoek 2005).","tracks":[{"project":"2_test","denotations":[{"id":"18818423-15306395-45167070","span":{"begin":73,"end":77},"obj":"15306395"},{"id":"18818423-14752165-45167071","span":{"begin":94,"end":98},"obj":"14752165"},{"id":"18818423-11522384-45167072","span":{"begin":884,"end":888},"obj":"11522384"},{"id":"T98505","span":{"begin":73,"end":77},"obj":"15306395"},{"id":"T8504","span":{"begin":94,"end":98},"obj":"14752165"},{"id":"T5167","span":{"begin":884,"end":888},"obj":"11522384"}],"attributes":[{"subj":"18818423-15306395-45167070","pred":"source","obj":"2_test"},{"subj":"18818423-14752165-45167071","pred":"source","obj":"2_test"},{"subj":"18818423-11522384-45167072","pred":"source","obj":"2_test"},{"subj":"T98505","pred":"source","obj":"2_test"},{"subj":"T8504","pred":"source","obj":"2_test"},{"subj":"T5167","pred":"source","obj":"2_test"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"2_test","color":"#ecdb93","default":true}]}]}}