Serum IL-17 in patients with erythema multiforme or Stevens–Johnson syndrome/toxic epidermal necrolysis drug reaction, and correlation with disease severity

Background: There is strong evidence that drug-induced cutaneous eruptions have an immunological component. Interleukin (IL)-17, a proinflammatory cytokine that is predominantly produced by T helper 17 cells, has been linked to various autoimmune and inflammatory diseases. Aim: To measure serum IL-17 levels in patients with cutaneous drug reactions [erythema multiforme (EM) and Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN)] in order to study the associations between IL-17 and disease severity. Methods: In total, 32 patients (13 with EM and 19 with SJS/TEN) and 15 age- and sex-matched healthy controls (HCs) were enrolled. Patients with SJS/TEN were assessed clinically using the SCORe of Toxic Epidermal Necrosis (SCORTEN) scale. Serum IL-17 levels were determined by ELISA. Results: Serum IL-17 levels were significantly higher compared with HCs (16.46 ± 5.21 pg/mL) in the EM (35.1 ± 23.89 pg/mL, P < 0.02) and SJS/TEN (68.19 ± 35.42 pg/mL, P = 0.001) groups. IL-17 levels were also significantly higher in the SJS/TEN group than in the EM group (P = 0.004). Mean affected body surface area percentage was 0.9 ± 0.21 in the EM group and 22.8 ± 10.67 in the SJS/TEN group. The SJS/TEN SCORTEN ranged from 1 to 5, with a mean of 2.5 ± 1. Serum IL-17 level correlated positively with both percentage surface area of detached skin and SCORTEN. Conclusions: Serum IL-17 levels may have prognostic and diagnostic value in patients with EM or SJS/TEN reactions, and can provide a valuable approach in managment.