Alopecia areata (AA) is a common autoimmune disease resulting from immune destruction of the hair follicle and subsequent hair loss. Despite its high prevalence, research into the pathogenesis and the development of innovative therapies in Alopecia Areata has lagged far behind other autoimmune diseases. Currently, there are no FDA approved drugs for Alopecia Areata. Abatacept is a safe intervention known to block costimulation and inflammatory responses in rheumatoid arthritis, which shares several susceptibility genes in common with Alopecia Areata. Both diseases share the involvement of CTLA4, which is the rationale for selecting Abatacept for evaluation in this clinical trial. CTLA4-Ig has been shown to prevent the onset of Alopecia Areata in the C3H-HeJ animal model of Alopecia Areata, demonstrating preclinical proof of concept data in Alopecia Areata.