Sonographic Pattern of Subacute Thyroiditis Is HLA-Dependent

Area of Science:

• Immunogenetics
• Medical Imaging
• Endocrinology

Background:

• Susceptibility to Silent Acute Thyroiditis (SAT) is linked to HLA-B*35 in ~70% of patients.
• Recent studies associate SAT with HLA-B*18:01, DRB1*01, and HLA-C*04:01.
• The relationship between genetic background and SAT sonographic patterns remains unexplored.

Purpose of the Study:

• To investigate the correlation between specific human leukocyte antigen (HLA) haplotypes and the sonographic presentation of Silent Acute Thyroiditis (SAT).
• To characterize the ultrasound (US) features of SAT lesions in relation to distinct HLA profiles.

Main Methods:

• Genotyping of HLA-A, -B, -C, -DQB1, and -DRB1 using next-generation sequencing in 46 SAT patients.
• Classification of patients into four groups based on specific HLA haplotypes, including combinations with HLA-B*35, HLA-C*04:01, HLA-DRB1*01, and HLA-B*18:01.
• Comparative analysis of ultrasound (US) patterns of SAT thyroid lesions across the defined HLA groups.

Main Results:

• Groups with HLA-B*35/HLA-C*04:01 or HLA-DRB1*01 (without HLA-B*18:01) exhibited similar US findings: hypoechoic, heterogeneous, bilateral, oval lesions with decreased vascularization.
• Patients with only HLA-B*18:01 showed distinct US features: predominantly homogeneous, hypoechoic, single unilateral lesions often filling the lobe.
• The HLA-B*18:01 plus HLA-B*35 group differed, with lesions lacking an oval shape.

Conclusions:

• The ultrasound (US) pattern of Silent Acute Thyroiditis (SAT) lesions is demonstrably influenced by human leukocyte antigen (HLA) type.
• The presence of HLA-B*18:01 is identified as a critical factor determining SAT's US characteristics.
• Significant deviations from typical SAT US imaging are most pronounced in patients solely positive for HLA-B*18:01, warranting further investigation.