Antiphospholipid antibodies in autoimmune thyroid diseases

Area of Science:

• Immunology
• Endocrinology
• Rheumatology

Background:

• Antiphospholipid (aPL) antibodies are associated with various autoimmune conditions.
• The presence and frequency of specific aPL, including anti-cardiolipin (aCL) and anti-β2 glycoprotein I (aβ2GPI) antibodies, in autoimmune thyroid diseases (AITD) require further investigation.

Purpose of the Study:

• To determine the prevalence of aPL, specifically aCL and aβ2GPI antibodies, in patients diagnosed with AITD.
• To compare the frequency of aPL between different types of AITD (Hashimoto's thyroiditis and Graves' disease) and healthy individuals.

Main Methods:

• Enzyme-linked immunosorbent assay (ELISA) was employed to detect IgG, IgA, and IgM isotypes of aCL and aβ2GPI antibodies.
• A cohort of 195 AITD patients (139 with Hashimoto's thyroiditis, 56 with Graves' disease) and 90 healthy blood donors were analyzed.

Main Results:

• A significantly higher frequency of aPL was observed in AITD patients (33.3%) and Hashimoto's thyroiditis (HT) patients (38.1%) compared to healthy blood donors (HBD) (11.1%).
• The frequency of aPL was lower in Graves' disease (GD) patients (21.4%) compared to HT patients (p=0.025).
• In HT patients, anti-β2 glycoprotein I antibodies (aβ2GPI) were significantly more prevalent (34.5%) than anti-cardiolipin antibodies (aCL) (13.6%). The IgA isotype of aβ2GPI was particularly elevated in HT patients compared to HBD and GD patients.

Conclusions:

• Anti-β2 glycoprotein I antibodies (aβ2GPI), rather than aCL, are frequently detected in patients with autoimmune thyroid diseases (AITD).
• The IgA isotype is the predominant form of aβ2GPI found in AITD.
• The prevalence of aβ2GPI-IgA is higher in Hashimoto's thyroiditis (HT) compared to Graves' disease (GD).