title: MICA4/HLA-DRB1*04/TNF1 haplotype is associated with mixed connective tissue disease in Swedish patients.
abstract: In order to investigate major histocompatibility complex (MHC) class I chain-related gene A (MICA), tumor necrosis factor (TNFa), -308TNFA, and human leukocyte antigen (HLA-DR/DQ) polymorphisms in mixed connective tissue disease (MCTD), we analyzed 24 patients and 229 healthy controls from Sweden. MICA and TNFa typing was performed by polymerase chain reaction (PCR) and genotyping. HLA-DR and -DQ were genotyped using PCR-sequence specific primers (PCR-SSP) and PCR-sequence-specific oligonucleotide probe (PCR-SSOP), respectively. For analysis of -308TNFA polymorphisms we performed PCR with restriction endonuclease enzymes. We found that the MICA5.1-5.1 genotype was positively associated with MCTD. Shared epitope genes (DRB1*01 and DRB1*04) were also significantly positively associated with MCTD. Polymorphism of -308TNFA was not differently distributed in MCTD patients compared with controls. Furthermore, we demonstrated that frequencies of three estimated haplotypes were increased in MCTD patients compared with controls. Interestingly, the haplotype with MICA allele 4 together with DRB1*04 and TNF1 alleles gives the most specific pattern for MCTD patients compared with controls. Our study demonstrates a clear contribution of HLA loci in susceptibility to MCTD in the Swedish population. Susceptibility to MCTD may be linked to the MICA4/HLA-DRB1*04/TNF1 haplotype and MICA 5.1-5.1 genotype. Mixed connective tissue disease was also associated with shared epitope genes, which in RA has been associated with a more severe disease. Whether these genotypes affect the clinical phenotype of MCTD needs to be determined.
authors.affiliation: Rheumatology Unit, Department of Medicine, Karolinska Institutet, Karolinska Hospital S-171 76, Stockholm, Sweden. adla.hassan@cmm.ki.se
authors.forename: Adla B
authors.initials: AB
authors.lastname: Hassan
authors.forename: Liene
authors.initials: L
authors.lastname: Nikitina-Zake
authors.forename: Leonid
authors.initials: L
authors.lastname: Padyukov
authors.forename: Göran
authors.initials: G
authors.lastname: Karlsson
authors.forename: Manu
authors.initials: M
authors.lastname: Gupta
authors.forename: Ingrid E
authors.initials: IE
authors.lastname: Lundberg
authors.forename: Carani B
authors.initials: CB
authors.lastname: Sanjeevi
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D001327:Autoimmune Diseases / Q000453:epidemiology / Q000235:genetics*; D000939:Epitopes / Q000235:genetics; D005260:Female; D005802:Genes, MHC Class II; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006239:Haplotypes / Q000235:genetics*; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D008947:Mixed Connective Tissue Disease / Q000453:epidemiology / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012306:Risk; D013548:Sweden / Q000453:epidemiology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D000939:Epitopes; D006683:HLA-DQ Antigens; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; C069050:HLA-DQA1 antigen; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A; D014409:Tumor Necrosis Factor-alpha