Endocrine Abstracts

Objectives: Human CD3⁺CD20⁺ T cells represents 3-5% of circulating T cells and may be detected in all lymphatic organs and in the cerebrospinal fluid. In healthy individuals CD3⁺CD20⁺ T cells have been shown to produce higher levels of IL-17A and/or IFN-γ than those of CD3⁺CD20^- T cells. Some reports described the role of CD3⁺CD20⁺ T cells in autoimmune disorders such as multiple sclerosis and rheumatoid arthritis possibly due their ability to produce these inflammatory cytokines. This study is aimed at describing the behavior of CD3⁺CD20⁺ T lymphocytes in patients in the most frequent autoimmune disorder i.e., Hashimoto’s thyroiditis, isolated or associated to further autoaggressive disorders in a frame of poly-autoimmunity.

Methods: The study group encompasses 65 patients bearing HT aged from 23 to 69 years (M=14; F=51), 42 of them associate another non-endocrine autoimmune disorder [16 with gastric atrophy (HT+GA), 15 with nonsegmental vitiligo (HT+V) and 11 with celiac disease (HT+CD)]. Twenty sex- and age-matched healthy subjects act as control group (HD). The chronic use of interfering drugs, severe or chronic disorders, pregnancy and lactation were used as exclusion criteria. Whole blood samples (100 microliters) were stained with the fluorescent-labelled antibodies. Red blood cells were then lysed by adding 1 ml of hypotonic buffer and samples were acquired on a FACs ARIA II Flow Cytometer (BD).

Results/Conclusions: The percentages of CD3⁺CD20⁺ and that of CD3⁺CD4⁺CD20⁺ lymphocytes were similar in HD HT and poly-autoimmune patients. The subpopulation CD3⁺ CD8⁺CD20⁺ was higher in the whole group of autoimmune patients as compared to HD (P=0.0089). Patients with isolated HT showed higher percentages of CD3⁺ CD8⁺CD20⁺ than in HD patients although not reaching statistical significance. However dividing HT group based on thyroid function, hypothyroid patients showed a doubled CD8 ⁺CD20⁺ percentages than HD patients (P=0.0115). The presence of associated autoimmune disorders did not change the CD8⁺CD20⁺ cells subset but the co-presence of GA increased this cells percentage as compared to HD (P=0.0257) unlike the patients with H+CD all in gluten-free diet, in whom the CD8 ⁺CD20⁺ subset was similar to the one in HD. These preliminary findings indicate that CD8 ⁺CD20⁺ cells may behave differently in HT patients with or without poly-autoimmunity and may be a provisional marker of inflammatory phase of auto aggressive disorders.