Expansion of CD8+ cells in autoimmune hemolytic anemia.

Autoimmune hemolytic anemia (AIHA) is a rare blood disease associated with the production of auto-antibodies and autoimmune hemolysis. A critical role of B-cells in the development of AIHA has been demonstrated before. Here, we present the analysis of the clonal T-cell populations in patients with AIHA. Thirty-three patients with AIHA were included in this study. Thirteen patients with other anemias, 14 patients with other autoimmune conditions (SLE - 6, RA - 8) and 20 healthy donors were included in the study as a control group. The clonality of T-cell was evaluated by the assessment of the T-cell receptor gamma and beta chain gene rearrangements (TCRG and TCRB). The incidence of T-cell monoclonality detected in patients with AIHA was significantly higher compared to the control group. The persistence of T-cell clones did not correlate with the level of hemoglobin and other signs of remission or relapse and did not disappear after the therapy and clinical improvement (observation period was between 1 and 10 years). There was no correlation between the T-cell clonality and the gender, age, splenectomy, duration or severity of the disease. Fractionation of T-lymphocytes (CD4+, CD8+, CD4+25+) revealed that the monoclonal T-cells belonged to the CD8+ sub-population. We assume that besides a possible causative role of the T-cell clones in AIHA to autoimmune process, these clones do not directly participate in the development and maintenance of hemolysis. Most of the AIHA patients (48.5%) demonstrated a T-cell monoclonality, which requires monitoring and should be distinguished from T-cell tumors.