Assessment of Serum Interleukin-15 in Alopecia Areata patients

Background: Alopecia Area (AA) is the most common cause of non-scaring alopecia. Its incidence reached up to 3.8%. it is considered as an autoimmune disease. However, its onset, course and response to treatment are not predictable. Interleukin-15 (IL-15) seems to play a crucial pathogenetic role. However, the evidence is not conclusive. The current work aimed to measure the IL-15 values in AA, comparing it to healthy volunteers and investigates its potential association with disease activity and severity and its diagnostic role. Methodology: This is a case-control comparative study, which included 80 subjects (40 with AA and 40 age and sex-matched healthy controls). All were clinically evaluated and serum levels of IL-15 were measured and correlated with disease severity (determined by Severity of Alopecia Tool (SALT)). Dermoscopy was performed to confirm the diagnosis. Results: Both study and controls were comparable regarding patient demographics. However, 52.5% of the cases had active disease, and 20% had severe disease. There was a significant increase of IL-15 in the cases than the control group (median values were 542.66 vs 264.54, respectively) However, there was no significant association between serum IL-15 and each of patient age, sex and marital status. But there was a significant higher value of IL-15 among cases with severe than active and or stable disease (646.8, than 537.5 or 456.76, respectively). IL-15 is a good test for diagnosis of AA. The area under curve (AUC) was excellent (0.944). The best detected cut off point was 368.06 yielding sensitivity of 97.5%, specificity 85% and total accuracy 91.3%.Conclusion: IL-15 could be considered as a valid and reliable indicator for disease development and progress. It also can be used as a follow up marker for treatment.