科学家发现O型血可以防止儿童出现严重的、威胁生命的疟疾。他们希望这一发现有助于找到治疗其它血型儿童的重症疟疾的疗法。

   他们的这一研究发表在了10月30日出版的《美国科学院学报》上。

　　由英国爱丁堡大学的Alex  Rowe领导的这个研究组从马里Bandiagara地区的患有重症疟疾、非重症疟疾以及健康的儿童身上获取了血样。他们发现O型血的儿童比A型和B型血的儿童出现重症疟疾的可能性低66%。

　　O型血比非O型血的儿童的血液中含有更少的红细胞“团块”，或称为“花结”（Rosettes）。当被恶性疟原虫感染的红细胞与未被感染的红细胞粘在一起时，花结就出现了，这可能是为了让疟原虫躲避宿主的免疫系统。

　　通过阻挡血流通过小血管，花结对重症疟疾也有贡献。Rowe说：“O型血的儿童很少存在花结。”

　　她还说：“[该研究]向我们证实了花结对于重症疟疾的重要性。如果我们可以改变花结的形成，我们就可能让A型血或者B型血儿童的血液行为像O型血儿童那样很少出现花结。这可能成为患有最严重疟疾的儿童的一种有用的治疗方法。”

　　这组科学家打算开发一种药物“打破”重症疟疾儿童血液中的花结。他们已经找到了一种候选化合物硫酸多糖，但是它可能导致出血。Rowe说：“我们正在设法开发基于硫酸多糖的第二代药物，它能破坏花结，但是不会导致出血。”

　　“看上去我们有希望能把这两种作用分开，开发出一种没有这些副作用的药物——尽管还需要进行许多研究。”（科学与发展网络）

原始出处：

Published online before print October 24, 2007, 10.1073/pnas.0705390104
PNAS | October 30, 2007 | vol. 104 | no. 44 | 17471-17476
OPEN ACCESS ARTICLE
BIOLOGICAL SCIENCES / MEDICAL SCIENCES

Blood group O protects against severe Plasmodium falciparum malaria through the mechanism of reduced rosetting

J. Alexandra Rowe*, , Ian G. Handel*, Mahamadou A. Thera, Anne-Marie Deans*, Kirsten E. Lyke, Abdoulaye Koné, Dapa A. Diallo, Ahmed Raza*, Oscar Kai¶, Kevin Marsh¶, Christopher V. Plowe, Ogobara K. Doumbo, and Joann M. Moulds||

*Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, United Kingdom; Malaria Research and Training Centre, Faculty of Medicine, Pharmacy, and Dentistry, University of Bamako, BP1805 Bamako, Mali; Center for Vaccine Development, Department of Medicine, University of Maryland, 685 West Baltimore Street, Baltimore, MD 21201; ¶KEMRI/Wellcome Laboratories, P. O. Box 230, Kilifi 80108, Kenya; and ||Lifeshare Blood Centers, 8910 Linwood Avenue, Shreveport, LA 71106

Edited by Francisco J. Ayala, University of California, Irvine, CA, and approved September 10, 2007 (received for review June 8, 2007)

Malaria has been a major selective force on the human population, and several erythrocyte polymorphisms have evolved that confer resistance to severe malaria. Plasmodium falciparum rosetting, a parasite virulence phenotype associated with severe malaria, is reduced in blood group O erythrocytes compared with groups A, B, and AB, but the contribution of the ABO blood group system to protection against severe malaria has received little attention. We hypothesized that blood group O may confer resistance to severe falciparum malaria through the mechanism of reduced rosetting. In a matched case-control study of 567 Malian children, we found that group O was present in only 21% of severe malaria cases compared with 44–45% of uncomplicated malaria controls and healthy controls. Group O was associated with a 66% reduction in the odds of developing severe malaria compared with the non-O blood groups (odds ratio 0.34, 95% confidence interval 0.19–0.61, P < 0.0005, severe cases versus uncomplicated malaria controls). In the same sample set, P. falciparum rosetting was reduced in parasite isolates from group O children compared with isolates from the non-O blood groups (P = 0.003, Kruskal–Wallis test). Statistical analysis indicated a significant interaction between host ABO blood group and parasite rosette frequency that supports the hypothesis that the protective effect of group O operates through the mechanism of reduced P. falciparum rosetting. This work provides insights into malaria pathogenesis and suggests that the selective pressure imposed by malaria may contribute to the variable global distribution of ABO blood groups in the human population.

                                                     摘自《生物谷》