Aim of the study: To investigate the percentage of CD4+CD25 high cells (including Treg cells) and CD8+CD28– cells in breast cancer patients with and without high levels of autoimmune thyroid antibodies. Material and methods: Thirty-five women with breast cancer (9 of them having high thyroid antibodies) and fourteen healthy subjects were enrolled in this study. Flow cytometry was used to count CD4+CD25 high cells and CD8+CD28– suppressive cells (CD8 cell subtypes). Results: In the patient group, the percentage of CD28– cells in CD8+ lymphocytes were higher [67.50% (55.11 80.33) vs. 51.56% (42.57 66.38); p = 0.021] and the percentage of CD28+CD45RO– cells (memory cells) in CD8+ lymphocytes were lower than in the control group. CD4+CD25 high cell percentage in CD4+ lymphocytes was elevated in the patient group [6.44% (4.52 8.74) vs. 2.97% (1.724.34); p < 0.001]. When the cytometric parameters were compared between patients (with high vs. normal thyroid antibodies), the distribution of CD8+ cell subgroups was also similar. CD4+CD25 high cells among CD4+ lymphocytes were decreased in patients with high levels of thyroid antibodies [5.19% (3.42 6.17) vs. 6.99% (4.82 9.95); p = 0.043]. Conclusions: CD4+CD25 high cells may play a role in autoimmunity of breast cancer patients, and may be a predictive marker. Advanced studies which evaluate the possible links between regulatory cells and autoimmunity should be established in cancer patients.
