title: Complement receptor 1 variants confer protection from severe malaria in Odisha, India.
abstract: BACKGROUND
  In Plasmodium falciparum infection, complement receptor-1 (CR1) on erythrocyte's surface and ABO blood group play important roles in formation of rosettes which are presumed to be contributory in the pathogenesis of severe malaria. Although several studies have attempted to determine the association of CR1 polymorphisms with severe malaria, observations remain inconsistent. Therefore, a case control study and meta-analysis was performed to address this issue.
  
  
  METHODS
  Common CR1 polymorphisms (intron 27 and exon 22) and blood group were typed in 353 cases of severe malaria (SM) [97 cerebral malaria (CM), 129 multi-organ dysfunction (MOD), 127 non-cerebral severe malaria (NCSM)], 141 un-complicated malaria and 100 healthy controls from an endemic region of Odisha, India. Relevant publications for meta-analysis were searched from the database.
  
  
  RESULTS
  The homozygous polymorphisms of CR1 intron 27 and exon 22 (TT and GG) and alleles (T and G) that are associated with low expression of CR1 on red blood cells, conferred significant protection against CM, MOD and malaria deaths. Combined analysis showed significant association of blood group B/intron 27-AA/exon 22-AA with susceptibility to SM (CM and MOD). Meta-analysis revealed that the CR1 exon 22 low expression polymorphism is significantly associated with protection against severe malaria.
  
  
  CONCLUSIONS
  The results of the present study demonstrate that common CR1 variants significantly protect against severe malaria in an endemic area.
authors.affiliation: Infectious Disease Biology Group, Institute of Life Sciences, Bhubaneswar, Odisha, India.
authors.forename: Aditya K
authors.initials: AK
authors.lastname: Panda
authors.forename: Madhumita
authors.initials: M
authors.lastname: Panda
authors.forename: Rina
authors.initials: R
authors.lastname: Tripathy
authors.forename: Sarit S
authors.initials: SS
authors.lastname: Pattanaik
authors.forename: Balachandran
authors.initials: B
authors.lastname: Ravindran
authors.forename: Bidyut K
authors.initials: BK
authors.lastname: Das
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D016022:Case-Control Studies; D005091:Exons / Q000235:genetics; D005260:Female; D056726:Genetic Association Studies; D018740:Genetic Heterogeneity; D020022:Genetic Predisposition to Disease; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007194:India; D007438:Introns / Q000235:genetics; D016778:Malaria, Falciparum / Q000235:genetics* / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011379:Prognosis; D017594:Publication Bias; D017463:Receptors, Complement 3b / Q000235:genetics*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000017:ABO Blood-Group System; C509991:CR1 protein, human; D017463:Receptors, Complement 3b