Immunological Characteristics of Children with Hashimoto's Autoimmune Thyroiditis.

The main cause of autoimmune thyroiditis of Hashimoto's type (HT) is a pathological immune response to thyroid antigens. The aim of the study was to present clinical characteristics and immune profile of children with HT. Ninety five children were examined: 45 with HT (age: 8-18 years) and 50 healthy age-matched controls. The peripheral blood mononuclear cells' (PBMC) phenotype was evaluated using a Beckman Coulter flow cytometer with the following monoclonal antibodies: CD4-FITC, CD28-PC5, CD152-PE and CD8-FITC, CD28-PC5, CD152-PE. The thyroid stimulating hormone, thyroid hormones, and antibodies against thyroid peroxidase (TPO) and thyroglobulin (TG) were evaluated by a microparticle enzyme immunoassay. We found that goiter was present in 53% of children, the thyroid had an increased density in palpation in 98%, and hypothyroidism was diagnosed in 11% of HT patients. The number of CD152+ was lower in HT than in healthy children (p<0.05). CD4+ and CD8+ PBMC subsets did not differ between the groups at baseline. After stimulation with phytohemagglutinine (PHA), CD4+ cells decreased in healthy controls and remained constant in HT children. Anti-TPO and anti-TG antibodies were higher in children with a lower percentage of CD152+. No other markers correlated with the immunological profile of PBMC. The percentages of CD4+ and CD152+ negatively correlated with the anti-TG concentration. We conclude that children with HT have a different PBMC profile than healthy children and show a different pattern of response to stimulation.