title: A dysfunctional allele of the mannose binding protein gene associates with systemic lupus erythematosus in a Spanish population.
abstract: OBJECTIVE
  To determine dysfunctional mannose binding protein (MBP) status of Spanish patients with systemic lupus erythematosus (SLE) and to determine whether MBP and complement C4 null alleles contribute in an additive way to SLE susceptibility.
  
  
  METHODS
  The frequencies of MBP alleles (characterized by polymorphisms at codon 54 and codon 57 of exon 1) were determined by the amplification refractory mutation system-polymerase chain reaction in 50 Spanish patients with SLE and 49 matched controls. Mutant genotypes for the codon 54 mutation were confirmed using a Ban I restriction enzyme digest method. Complement C4 allotyping was achieved by agarose gel electrophoresis of neuraminidase/carboxypeptidase B digested plasma samples followed by immunofixation and staining.
  
  
  RESULTS
  At least one dysfunctional MBP allele, unable to activate complement, was present in 52% of patients with SLE and in 31% of controls (OR = 2.4, 95% CI 1.1-5.6). Complement C4 null alleles (either C4A or C4B) were present in 61% of patients and 43% of controls (OR = 2.1, 95% CI 0.9-4.9). A dysfunctional MBP allele and C4 null allele were present in 41% of patients and 16% of controls (OR = 3.2, 95% CI 1.2-8.1).
  
  
  CONCLUSIONS
  The presence of a dysfunctional MBP allele is a risk factor for developing SLE in this Spanish population and may affect susceptibility in an additive way with C4 null alleles.
authors.affiliation: Rheumatic Diseases Centre, University of Manchester, UK.
authors.forename: E J
authors.initials: EJ
authors.lastname: Davies
authors.forename: L S
authors.initials: LS
authors.lastname: Teh
authors.forename: J
authors.initials: J
authors.lastname: Ordi-Ros
authors.forename: N
authors.initials: N
authors.lastname: Snowden
authors.forename: M C
authors.initials: MC
authors.lastname: Hillarby
authors.forename: A
authors.initials: A
authors.lastname: Hajeer
authors.forename: R
authors.initials: R
authors.lastname: Donn
authors.forename: P
authors.initials: P
authors.lastname: Perez-Pemen
authors.forename: M
authors.initials: M
authors.lastname: Vilardell-Tarres
authors.forename: W E
authors.initials: WE
authors.lastname: Ollier
mesh_terms: D000209:Acute-Phase Proteins / Q000235:genetics; D000483:Alleles; D002352:Carrier Proteins / Q000235:genetics*; D002879:Chromosomes, Human, Pair 10 / Q000235:genetics; D003181:Complement C4 / Q000235:genetics; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000453:epidemiology / Q000235:genetics*; D008297:Male; D008358:Mannose; D037241:Mannose-Binding Lectins; D010641:Phenotype; D017354:Point Mutation; D013030:Spain / Q000453:epidemiology
chemical_list: D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D003181:Complement C4; D037241:Mannose-Binding Lectins; D008358:Mannose