ABSTRACT
Background: Interleukin‑15 (IL‑15) is a cytokine that is involved in many inflammatory and
autoimmune diseases. Although alopecia areata (AA) is an autoimmune disease, serum
levels of IL‑15 have not been studied well in AA patients. Aim of the Work: We aims at
evaluating the serum levels of IL‑15 in active AA. Subject and Methods: This case‑control
study included 40 AA patients and 40 apparently healthy matched controls. Written informed
consents were obtained from all the participants. The scalp was examined to assess sites,
number, and size of alopecia patches, and the severity of AA lesions was assessed using
the Severity of Alopecia Tool score (SALT score) which determine the percentage of hair
loss in the scalp. The body was carefully examined to detect any alopecia patches in any
hairy area. Nail examination was carried out to detect any nail involvement. Serum IL‑15
levels were measured using an ELISA kits. Results: Serum levels of IL‑15 in patients were
significantly higher than those in the control group (P < 0.001). Serum levels in alopecia
totalis were significantly higher than those with one or two patches, and serum levels in
patients with both scalp and body involvement were significantly elevated than the levels of
patients with either scalp or body involvement. There was a statistically significant positive
correlation between SALT score and serum levels of IL‑15 (P < 0.001). Conclusion: Serum
IL‑15 may be a marker of AA severity.