title: IL-33 reflects dynamics of disease activity in patients with autoimmune hemolytic anemia by regulating autoantibody production.
abstract: BACKGROUND
  Autoimmune hemolytic anemia (AIHA), a life-threatening anemia with rapid onset, is caused by autoantibody directed to self red blood cells (RBCs). Currently, mechanisms underlying AIHA pathogenesis are largely undefined. Here we explored the correlation of IL-33 with AIHA disease activity and evaluated IL-33 based therapeutics in AIHA treatment.
  
  
  METHODS
  Thirty patients diagnosed with AIHA of warm-type autoantibodies without treatment were enrolled and followed up for 6 months. Levels of cytokines including IL-33, IL-4, IL-6 and IL-13 was determined with ELISA. AIHA disease activity was presented by levels of reticulocyte count, hemoglobin and lactate dehydrogenase. Serum RBC-bound IgG autoantibody was detected using anti-IgG antibody with flow cytometry. To evaluate the effect of IL-33 blockade on AIHA development, groups of B6 mice were immunized with rat RBCs plus recombinant IL-33 protein or IL-33 neutralizing antibody respectively and detected for levels of anti-RBC antibody, frequency of reticulocytes and destruction of transfused syngeneic mouse RBCs.
  
  
  RESULTS
  Serum level of IL-33 was higher in AIHA patients compared with healthy individuals. Of interest, serum IL-33 was positively correlated with AIHA disease activity and sensitive to their changes in AIHA patients under clinical management. Mechanistically, IL-33 could promote the production of anti-RBC autoantibody. Serum IL-33 was closely associated with serum anti-RBC autoantibody and sensitive to their changes in AIHA patients. Accordingly, blockade of IL-33 interfered with AIHA incidence and ameliorated disease activity. Vice vasa, enforced IL-33 promoted AIHA incidence and disease activity.
  
  
  CONCLUSIONS
  IL-33 was a potential biomarker for monitoring disease activity and therapeutic response in AIHA patients. Targeting IL-33 was a promising strategy for controlling autoantibody production in AIHA patients.
authors.affiliation: Department of Clinical Laboratory, Qingdao Women & Children Hospital, Qingdao, 266034, Shandong, China. xmbuqd@126.com.
authors.forename: Xiangmao
authors.initials: X
authors.lastname: Bu
authors.affiliation: Department of Oncology, Qingdao Municipal Hospital, Qingdao, 266071, Shandong, China. adamkingw@163.com.
authors.forename: Tenglong
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Department of Respiratory Medicine, East Hospital, Tongji University School of Medicine, 150 Jimo Road, Shanghai, 200120, China. wangch910@126.com.
authors.forename: Chunhong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Respiratory Medicine, East Hospital, Tongji University School of Medicine, 150 Jimo Road, Shanghai, 200120, China. rentaosh@126.com.
authors.forename: Tao
authors.initials: T
authors.lastname: Ren
authors.affiliation: Institute of Immunobiology, Shanghai Medical College of Fudan University, Shanghai, 200032, China. wenzk@126.com.|Division of Immunology and Rheumatology, Stanford University School of Medicine, 269 Campus Drive West, Stanford, CA, 94305, USA. wenzk@126.com.
authors.forename: Zhenke
authors.initials: Z
authors.lastname: Wen
mesh_terms: D000744:Anemia, Hemolytic, Autoimmune / Q000276:immunology / Q000503:physiopathology*; D001323:Autoantibodies / Q000096:biosynthesis*; D006801:Humans; D000067596:Interleukin-33 / Q000097:blood / Q000502:physiology*
chemical_list: D001323:Autoantibodies; C506536:IL33 protein, human; D000067596:Interleukin-33