There is an estimated lifetime risk of 1.7% for sufferers of autoimmune hair loss condition Alopecia areata (AA). Alopecia areata (AA) is a common symptom of AA, and it may affect any part of the body. Prevalence among young and middle-aged individuals ranges from 0.9% to 6.9 percent. Most individuals (50–60 percent) acquire AA before they are 20 years old, however the condition may arise at any time. However, genetic and environmental variables have been shown to have a significant role in the development of AA. It has been suggested that the collapse of the immune privilege of the hair follicle is a crucial factor in the development of Alzheimer's disease. As a 40kDa type 1 transmembrane protein, programmed death-ligand 1 (PD-L1) plays a crucial role in dampening the adaptive arm of the immune system, according to some researchers. Additionally, PD-L1 helps to build immunological privilege sites. PD-L1 levels in patients with AA were studied to see whether they were associated with disease severity. Researchers used 60 men and women with AA and 20 healthy volunteers for this case-control research at the Dermatology and Andrology Clinic at the Benha University Hospitals. An ELISA method and the SALT score were used to determine the severity of illness in the patients' group for programmed death ligand 1 serum levels. There were no significant variations in age or sex between the groups in this investigation. There are no major variations in family history between the two groups. In 10% of instances, a member of the patient's family had a history of alcoholism. SALT scores were used to determine severity. There was a significant difference between the AA group and the control group in terms of PD-L1 levels in the present research. SALT score was positively correlated with PD-L1 level. PD-L1 was shown to be an independent predictor of AA severity. The findings of this research show that PD-L1 has a role in the aetiology of AA. As an indicator of the severity of the condition, PD-L1 might be employed. In addition, this research might lead to the development of novel treatment options for AA patients.