Endocrine Abstracts

Aims: Presence of antinuclear antibodies (ANA) is correlated to tissue involutive lesions by microvascular alterations. The possible involvement of hypovitaminosis D as a negative immunomodulatory factor along with the presence of ANA and the incidence of chronic autoimmune thyroiditis (CAT) atrophic form is a complex mechanism with multiple pathological intercorrelations.

Material and method: Inclusion criteria: patients - new cases diagnosed with CAT without other associated autoimmune diseases and without specific thyroid therapy. Variables studied: serum pathological ANA level. Serum level 25-OH-vitamin D (normal and moderate/severe low); incidence of atrophic CAT/absence of intrathyroid vascular Doppler signal. Group 1: n=56; 25-OH-vit D: 20–29 ng/ml; Group 2: n=41; 25-OH-vit D <19 ng/ml; Group 3: n=43; 25-OH-vit-D > 30 ng/ml.

Results: Incidence of pathological serum ANA level: Lot 1: 31 (55.3%); Lot 2: 22 (53.7%); Lot 3: 12 (28%). Incidence of atrophic form of CAT: Lot 1: 28 (50%); Lot 2: 37 (90%); Lot 3: 4 (9.3%).

Discussion: The presence of ANA (P<0.05) was not significant between group 1/group 2 and significant (P<0.001) for both versus group 3. Incidence of atrophic form of CAT between group 1/group 2 (P<0.001) versus group 3 (P<0.001) – with a minimal incidence. The presence of ANA in patients with CAT may have a thyroid involutive effect. The low serum level of vitamin D is directly proportional to the incidence of atrophic CAT in positive ANA patients. Hypovitaminosis D appears to be involved depending on the severity of the deficiency without excluding its duration.

Conclusions: The role of ANA in the thyroid involutive process seems possible and the early correction of hypovitaminosis D in patients with CAT could have an effective therapeutic method.