Caspase-1 and interleukin-18 in children with post infectious bronchiolitis obliterans

Abstract

Introduction: The exact immunological mechanisms of post infectious bronchiolitis obliterans (PIBO) in childhood are not fully known.

Aims and objectives: To investigate the role of caspase-1, IL-18, and IL-18 components in PIBO.

Methods: From January to May 2020, children with PIBO, children with history of influenza infection without PIBO and healthy children were asked to participate in the study in three pediatric pulmonology centers. Serum caspase-1, IL-18, IL-18BP, IL-18R and INF-γ levels were measured by enzyme-linked immunosorbent assay (ELISA) and compared between the 3 groups.

Results: There were, 21 children in PIBO group, 16 children in influenza group and 39 children in healthy control group in the study. No differences in terms of age and gender between the 3 groups were found (p>0.05). IL-18 and IL-18BP levels were higher in healthy control group (p=0.018, p=0.005, respectively). IL-18R was higher in PIBO group (p=0.001) and caspase-1 was higher in PIBO and influenza group than the healthy control group (p=0.002). IFN-γ levels did not differ between the 3 groups. IL-18BP/IL-18 was higher in the influenza group than the PIBO group and the healthy control group (p=0.003).

Conclusion: Caspase-1 level was increased in patients with PIBO which suggests that inflammasome activation may have a role in fibrosis, however IL-18 level was found to be low. Mediators other than IL-18 may be involved in the inflammatory pathway in PIBO. Further immunological studies investigating inflammasome pathway are needed for PIBO with chronic inflammation.

Funding: This work has been supported by Gazi University Scientific Research Projects Coordination Unit under grant number 01/2020-16.