The HLA-DR4-associated DQw8 allele is confined to HLA-DR3/DR4 heterozygous type I (insulin-dependent) diabetics.
The HLA-DR4 specificity revealed a relative risk of 8.5 (chi 2 = 99.6; p less than 0.0001) when 193 type I diabetics were compared to 305 controls. Prevalence of the HLA-DR4-associated DQ types, i.e. DQw7 and DQw8, were determined, using a restriction fragment length polymorphism (RFLP) typing that combines the probe/enzyme combinations DQB/Taq I and DQB/Bam HI. The HLA-DQw8 specificity was confined to HLA-DR3/DR4 heterozygous patients when compared to controls (chi 2 = 4.9; p less than 0.025) or to all other DR4-heterozygous patients (chi 2 = 6.7; p less than 0.01). No association with HLA-DQw8 was seen in HLA-DR1/DR4 or HLA-DR"X"/DR4 (X not equal to 1,3,4) heterozygous patients. Due to the excess of HLA-DR3/DR4 patients the DQw8 allele is a risk factor in type I diabetics, but in HLA-DR1/DR4 and DRX/DR4 heterozygotes one might suggest that DQB1 and DRB combinations confer HLA-associated susceptibility.
Boehm
B O
BO
University Hospital of Frankfurt Medical School, Department of General Medicine, Germany.
Schifferdecker
E
E
Rosak
C
C
Kuehnl
P
P
Driesel
A J
AJ
Schöffling
K
K
D000483:Alleles; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology*; D005858:Germany; D006683:HLA-DQ Antigens / Q000235:genetics*; D015803:HLA-DR3 Antigen / Q000235:genetics*; D015804:HLA-DR4 Antigen / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D012150:Polymorphism, Restriction Fragment Length
D006683:HLA-DQ Antigens; C109756:HLA-DQ8 antigen; D015803:HLA-DR3 Antigen; D015804:HLA-DR4 Antigen