The role of interleukin-22 in pityriasis rosea

Background. Pityriasis rosea (PR) is an exanthematous disease related to reactivation of human herpes virus (HHV) types 6 and 7. The pathogenesis and cytokine profile of PR are still poorly understood. There is a large amount of evidence indicating a viral aetiology for PR. Aim. To measure the serum level of interleukin (IL)-22, a cytokine expressed by T helper (Th) 17 cells in patients with PR to explore the possible association of IL-22 with the pathogenesis of the disease. Methods. This case-control study enrolled 25 patients with PR (mean +/- SD age 20 +/- 12 years) and a control group of 25 apparently healthy individuals (mean age 18 +/- 12.1 years). Blood samples were collected from both patients and controls to measure serum IL-22. Scoring of PR was performed using the Pityriasis Rosea Severity Score (PRSS). Results. There was a statistically significant difference in IL-22 serum level between the patient and control groups. The IL-22 serum level increased with increase in disease severity (PRSS), extent and duration. Conclusion. Through its proinflammatory cytokines, IL-22 plays a role in the inflammatory process of PR.