Association of HLA DQ4-DR8 haplotype with papillary thyroid carcinomas.

OBJECTIVE: The association of the human leucocyte antigen (HLA) system with thyroid carcinomas is not clear. We sought to relate HLA alleles to susceptibility to papillary thyroid carcinoma (PTC) and also to clinical and pathological characteristics of PTC patients. DESIGN AND PATIENTS: The distribution of HLA in 181 unrelated Caucasian patients with PTC was compared to the HLA distribution in 315 normal controls, 31 patients with follicular carcinoma (FTC), 29 patients with lymphocytic thyroiditis (LT) and 50 patients with multinodular goitre (MNG), using a microlymphocytotoxicity assay. RESULTS: Compared to normal controls, patients with PTC showed a significantly increased frequency of HLA-DQ4 [12.8%vs. 3.5%, P=0.0005, P(corrected) (P(c))=0.0032, odds ratio (OR)=4.058, 95% confidence interval (95% CI)=1.820-9.045] and HLA-DR8 (10.9%vs. 4.3%, P=0.013, P(c) > 0.05, OR=2.752, 95% CI=1.275-5.940). DQ4 and DR8 were also significantly increased in patients with MNG (DQ4, 16.3%; DR8, 16.3%) compared to controls (DQ4, P=0.0019, P(c)=0.011, OR=5.420, 95% CI=1.978-14.852; DR8, P=0.0044, P(c)=0.062). Linkage disequilibrium (LD) for these two alleles was present in controls (D=0.0130, P=9.7e-57) and in MNG patients (D=0.0730, P=4.6e-19) but not in PTC patients (D=0.038, P>0.05). In the subgroup of PTC subjects with concomitant 0thyroidal neoplasias (n=27), there was a significant (P< 0.05) increase in the frequency of B57 (18.5%), DR11 (56.5%) and DQ3 (81.8%) compared to PTC patients without coexistent neoplasias (2.0%, 21% and 47%, respectively). No significant differences of HLA allele distribution was found in relation to PTC histology, age at diagnosis (> 45 or