Autoimmune hemolytic anemia (AIHA) is an acquired autoimmune disease resulting in the production of antibodies directed against the patient’s red blood cells (RBCs) causing destruction of red blood cells.T follicular helper (Tfh)  and T follicular regulatory cells (Tfr) perform opposing actions in regulating germinal center responses, the dysregulation of their actions may ultimately advance the development of autoimmune diseases. There is evidence indicates that patients with autoimmune diseases, such as rheumatoid arthritis, systemic Lupus Erythematosus and systemic sclerosis, exhibit imbalance of T follicular helper and T follicular regulatory cells Aim: to study the characteristics of T follicular helper and T follicular regulatory cells and analysis of T follicular helper/ T follicular regulatory cells ratio in autoimmune hemolytic anemia.

Participants and methods: The study was carried out on 50 patients with Autoimmune hemolytic anemia (primary not on treatment) who presented to Assuit university hospital and 25 healthy age and sex-matched controls. We determined T follicular helper and T follicular regulatory cells expression by flowcytometry using monoclonal antibody CD3,CD4, CD185 , PD-1 and Foxp3. Results: Within the CD3⁺CD4⁺lymphocytes we gated on CXCR5⁺   T cells (CD185) ,we determined the fraction of PD-1⁺ FOXP3^- and PD-1⁺ FOXP3⁺ from peripheral blood in patients with autoimmune hemolytic anemia to analyse T follicular helper ( CD4⁺ CXCR5⁺PD1⁺ Foxp3^-) and T follicular regulatory  (CD4⁺CXCR5⁺PD1⁺ Foxp3⁺) cells .There was statistically significant higher median expression level of Tfh (CD4⁺ CXCR5⁺PD1⁺ Foxp3^-) (26.70 vs 1.80 %), p <0.001 and lower median expression level of Tfr (CD4⁺CXCR5⁺PD1⁺ Foxp3⁺) cells among cases compared to controls (1.87 vs 33.30 %),p <0.001 .There was statistically significant higher T follicular helper /T follicular regulatory cells ratio among cases compared to controls(15.19 vs 0.09), p <0.001. Conclusion:  Our results suggested that the increased T follicular helper cells and decreased T follicular regulatory cells may be involved in immunopathogenesis of autoimmune hemolytic anemia.T follicular helper /T follicular regulatory cells ratio have the most important role in the pathogenesis of autoimmune hemolytic anemia. Our results may provide new insight about the role of T follicular helper as a new cellular target in AIHA treatment.