Endocrine Abstracts

Problem: Interleukin-17A (IL-17A) has a role in sustaining normal pregnancy. IL-17A isalso associated with thyroid autoimmunity during pregnancy. This study sought to investigate whether IL-17A is a risk factor for thyroid dysfunction during pregnancy without thyroid autoimmunity.

Methods of study: The study comprised 216 pregnant women with negative thyroid peroxidase antibody (TPOAb) andthyroglobulin antibodies (TGAb) during the second trimesterwho provided samples for serum IL-17A and thyroid function detection. To further evaluate the ratio of CD4 + IL-17A + Th17 cells, we collected peripheral blood from 26 participants with thyroid-stimulating hormone (TSH) levels 2.5 mIU/l and 26 pregnant-week matching populations with TSH levels >2.5 mIU/l, along with samples from 20 participants with TSH levels ≤4 mIU/l and 20 pregnant-week matching populations with TSH levels >4 mIU/l.

Results: The serum IL-17A levels and ratios of CD4 + IL-17A + cells were significantly lower in women with TSH > 2.5 mIU/l than in those with TSH ≤ 2.5 mIU/l (both P < 0.01). Similar lower differences were noted in women with TSH > 4 mIU/l (subclinical hypothyroidism) than in those with TSH ≤ 4 mIU/l (both P < 0.01). The IL-17A level (β = −0.195, P = 0.004) and week of gestation (β = 0.284, P = 0.000) were significant predictors of regression, with TSH as the dependent variable in all participants during the second trimester. Logistic regression indicated that a lower serum IL-17A level was a risk factor for TSH > 2.5 mIU/l [OR = 0.453 (0.298–0.689),P = 0.000] and subclinical hypothyroidism [OR = 0.588(0.385–0.899), P = 0.013].

Conclusion: A low serum IL-17A level during the second trimester is associated with an increased risk of TSH > 2.5 mIU/l and subclinical hypothyroidism.