[Cytofluorymetric evaluation of antigen regions of human thyroid peroxidase in patients with Graves' disease and non-toxic multinodular goiter using mouse monoclonal antibodies].

Abstract

The aim of this study was to estimate expression of surface antigen regions of TPO (thyroid peroxidase: #1, #18, #30, #64 epitopes) on thyroid cells in 15 patients with non-toxic multinodular goiter (NTMG) and 15 patients with Graves' disease (GD). The thyrocytes were identified by indirect method: in first stage we added mouse monoclonal autoantibodies specific for TPO regions and in second stage we conjugated this complex with rabbit anti-mouse antibodies IgG (Fab')2 with FITC. All investigations were performed by flow cytometry using apparatus Coulter EPICS XL. The percentages of thyroid cells with expression of antigen regions of TPO 1, 18, 30, 64 were measured in relationship to the responsible anti-TPO concentrations: 50, 100, 200, 400, 800, 1600 microg/ml. The analysis of the expression of epitope #64 TPO revealed insignificantly increased percentages of thyroid cells in patients with GD (73% vs 45%, ns) in comparison to NTMG at anti-TPO antibody concentration of 1600 microg/ml. In addition, we observed that reduction concentration of anti-TPO antibodies leads to the decreased percentage of thyroid cells with antigen region #64 expression. In patients with GD percentage of this cells was significantly higher (48% vs 7% p<0.019, 29% vs 56% p<0.05) in compared to the percentage of thyroid cells from patients with NTMG at concentration of 200-800 microg/ml anti-TPO antibodies. Analysis of epitopes #1 and #18 shown higher percentage of thyroid cells in GD (25% vs 20%, ns for #1 epitope) and (25% vs 13%, ns for #18 epitope) in comparison to the patients with NTMG at concentration 1600 microg/ml of anti-TPO antibodies. The percentages of thyrocytes with epitopes #1 and #18 were decreased in relation to the reduction of anti-TPO concentrations. However, in all our patients epitope #30 TPO was found only in 8% thyroid cells. We conclude that in young patients thyroid immune and nonimmune diseases predispose to elevated expression of TPO epitopes (#1, #18, #64) which suggested increase stimulation and activation of thyroid cells during inflammatory reaction within thyroid gland. Furthermore, dominance expression of #64 TPO epitope in Graves' patients which recognized B domain could be a useful marker of activity of immune process in concentration between 200-800 microg/ml of TPO antibodies.