Churg–Strauss syndrome (CSS) has a clear clinical phenotype but its pathogenesis is not fully elucidated. Recent studies have focused on its immunogenetic aspects and cytokine and chemokine-mediated pathogenetic mechanisms, providing the rationale for the use of newer targeted therapies. This study will review recent findings on the pathogenesis of CSS and its therapeutic approaches.
CSS is usually considered a Th2-mediated disease, but Th1 and Th17 responses might also play a role; the reported association between CSS and HLA-DRB4 further underlines the pathogenetic relevance of CD4+ T cells which, thanks to their ability to secrete cytokines such as IL4, IL5, and IL13, promote allergic and eosinophilic reactions. Resident cells such as endothelial and epithelial cells might also amplify the immune response by producing eosinophil-attracting chemokines such as eotaxin-3 and CCL17. Conventional immunosuppressive therapies offer high chances of achieving sustained remission, but steroid exposure remains high. Targeting IL5 with mepolizumab seems promising in sparing steroids, but relapses often follow its withdrawal. B-cell depletion using rituximab has proved effective in refractory CSS cases.
Current knowledge on CSS pathogenesis is evolving; the identification of key molecular mechanisms will pave the way for newer, more specific treatments.
aDepartment of Clinical Medicine and Nephrology, University Hospital of Parma, Parma, Italy
bUniversity Hospital of Schleswig Holstein and Klinikum Bad Bramstedt, Bad Bramstedt
cDepartment of Internal Medicine 3 and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Germany
dLudwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
Correspondence to Dr Augusto Vaglio, Dipartimento di Clinica Medica e Nefrologia, Azienda Ospedaliero-Universitaria di Parma, Via Gramsci 14, 43126 Parma, Italy. Tel: +39 0521 033176; fax: +39 0521 033185; e-mail: firstname.lastname@example.org