Autoimmune hemolytic anemia (AIHA) is an auto-immune disease mediated by specific antibodies targeting red blood cells. Its pathogenesis is not completely understood, and the role of T cells have been rarely studied.

The aim of this study is to compare the frequency of circulating T cells, T cell polarization and functions, notably regulatory T cells, during warm AIHA by comparison to healthy controls.

The role of treatments, such as steroids, will also be determined in patients with warm AIHA.

Inclusion Criteria:

• Patients diagnosed with primary warm Autoimmune Hemolytic Anemia (wAIHA)
• Secondary AHAI (infections, hematological diseases, systemic diseases)
• Naive of treatment for hemolytic anemia or in relapse
• Older than 16
• Able to understand written and spoken French
• who have provided written informed consent
• INCLUSION CRITERIA for CONTROLS
• Persons without auto-immune disease, cancer or active infection.
• Older than 16
• Able to understand written and spoken French
• who have provided written informed consent

Exclusion Criteria:

• Cold agglutinin disease
• Pregnancy
• Persons without national health insurance

Exclusion Criteria for Controls:

• Subjects treated with corticosteroids or immunosuppressants
• Pregnancy
• Persons without national health insurance

Patients diagnosed with warm primary or secondary Autoimmune Hemolytic Anemia