Clinical settings in which human leukocyte antigen typing is still useful in the diagnosis of celiac disease

Figure 1 Graphical representation of human leukocyte antigen genotypes grouped according to the current nomenclature of human leukocyte antigen molecules with the associated risk for celiac disease and type 1 diabetes. The symbol x indicates other human leukocyte antigen (HLA)-DQ alleles not associated with celiac disease (CD). The HLA-DQ2.5/HLA-DQ2.2, HLA-DQ2.5/HLA-DQ2.5, and HLA-DQ2.5/HLA-DQ8 molecules confer high risk for CD (see also Table 2). HLA-DQ2.5/HLA-DQ2.5 and HLA-DQ2.5/HLA-DQ8 molecules are also associated with type 1 diabetes (T1D), conferring high risk and very high risk, respectively. Interestingly, the HLA-DQ2.5/HLA-DQ2.2 molecule strongly associated with CD confers a low risk for T1D. The HLA-DQ2.2/HLA-DQ7.5 molecule conferring a moderate risk for CD has a low risk for T1D. The other HLA molecules are similarly associated with both diseases. HLA: Human leukocyte antigen; CD: Celiac disease; T1D: Type 1 diabetes.