Interleukin-22 levels in pediatric patients with gastrointestinal graft-versus-host disease

Dana T. Lounder from Division of Bone Marrow Transplant and Immune Deficiency, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA, and colleagues conducted a study to determine the role of circulating interleukin-22 (IL-22) levels in gastrointestinal graft-versus-host disease (GI GvHD) in pediatric patients undergoing hematopoietic stem cell transplant (HSCT). The study was published in Haematologica.

In order to assess whether IL-22 levels are elevated in pediatric patients with GI GvHD, the researchers analysed plasma samples obtained from 114 pediatric patients enrolled in a prospective cohort study, the Cincinnati Children’s Hospital Medical Center BMT repository.  At 30-days post-transplant, IL-22, IL-22 binding protein (IL-22BP), Reg3α, and IL-17 levels were analyzed using ELISA.

Patient characteristics:

• Median age: 8 years (range, 0.4–32)
• GvHD any site: 50 (44%)
  • Grade 1: 9 (18%)
  • Grades 2–4: 41 (82%)

Key findings:

Data is given as GvHD patients with IL levels above the median vs GvHD patients with IL levels below the median

• IL-22
  • The cumulative incidence of new onset acute GI GvHD 30 days after HSCT: 15.5% vs8%, P = 0.04
  • 1-year treatment-related mortality (TRM) rate: 46.9% vs 20%, P = 0.6
• IL-22BP
  • IL-22BP levels negatively correlated with IL-22 levels 30 days after HSCT, r = -0.2, P = 0.03
  • There was no significant association between IL-22BP levels and the development of GI GvHD
• IL-17
  • Incidence of GI GvHD 100 days after HSCT: 32% vs 14%, P = 0.03
  • IL-17 levels significantly correlated with IL-22 levels 30 days after HSCT: r = 0.43, P < 0.0001
• Reg3α
  • Reg3α levels negatively correlated with IL-22 levels: r = -0.22, P = 0.02
  • Reg3α levels also negatively correlated with IL-17 levels: r = -0.47, P < 0.0001

Taken together, this data indicates that IL-22 levels are elevated in patients with GI graft-versus-host disease without causing higher mortality rates in this patient population. The research group stated that because of the complex role of IL-22 as well as related molecules in the setting of post-transplant patients, further studies are required to completely clarify the method of these mechanisms.