title: A shift towards a T cell cytokine deficiency along with an anti-inflammatory/regulatory microenvironment may enable the synthesis of anti-FVIII inhibitors in haemophilia A patients.
abstract: Despite the clinical relevance of anti-factor VIII (FVIII) antibodies (anti-FVIII inhibitors) impairing haemostatic activity of haemophilia A (HA) patients, the immunological mechanisms underlying their production are unknown. Aiming to understand more clearly the immune response in patients with [HAα-FVIII(+)] and without [HAα-FVIII(-)] anti-FVIII inhibitors, we have characterized the cytokine pattern of peripheral blood leucocytes, using an in vitro stimulation of whole blood samples with plasma-derived (pFVIII) or recombinant FVIII (rFVIII). The results highlighted decreased levels of tumour necrosis factor (TNF)-α(+) neutrophils with higher interleukin (IL)-5/TNF-α ratio in HAα-FVIII(+). All HA samples displayed decreased levels of IL-10(+) monocytes when compared to the blood donor (BD) samples. HAα-FVIII(+) showed lower levels of TNF-α(+) monocytes and increased IL-10/TNF-α ratio. Analysis of adaptive immunity revealed increased levels of interferon (IFN)-γ(+) , TNF-α(+) and IL-4(+) T-cells, from both CD4(+) and CD8(+) T cells, in HAα-FVIII(-) when compared to BD. Moreover, increased frequency of IL-10(+) B cells and higher levels of α-FVIII IgG1 were observed in HAα-FVIII(-). Basal levels of cytokine(+) B-cells, similar to BD, and higher levels of α-FVIII IgG4 are major features in HAα-FVIII(+). The global cytokine profile demonstrated a major anti-inflammatory/regulatory pattern in HAα-FVIII(+), confirmed by the in vitro stimuli with pFVIII or rFVIII. The polarized anti-inflammatory/regulatory immune response in HAα-FVIII(+) and the mixed pattern with a bias towards an inflammatory cytokine profile, modulated by IL-4 in HAα-FVIII(-), may be the key element to drive the development of distinct subclasses of anti-FVIII antibodies. These finding have implications for the design of safe and effective therapeutic protocols to control inhibitors synthesis in HA patients.
authors.affiliation: Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. danielgcm@gmail.com
authors.forename: D G
authors.initials: DG
authors.lastname: Chaves
authors.forename: C
authors.initials: C
authors.lastname: Velloso-Rodrigues
authors.forename: C A
authors.initials: CA
authors.lastname: Oliveira
authors.forename: A
authors.initials: A
authors.lastname: Teixeira-Carvalho
authors.forename: M M
authors.initials: MM
authors.lastname: Santoro
authors.forename: O A
authors.initials: OA
authors.lastname: Martins-Filho
mesh_terms: D000293:Adolescent; D000328:Adult; D000917:Antibody Formation / Q000235:genetics; D001323:Autoantibodies / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002648:Child; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005169:Factor VIII / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006467:Hemophilia A / Q000097:blood / Q000235:genetics / Q000276:immunology* / Q000628:therapy; D006801:Humans; D007113:Immunity, Innate; D008213:Lymphocyte Activation; D008297:Male; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D058408:Th1-Th2 Balance
chemical_list: D001323:Autoantibodies; D016207:Cytokines; C078147:F8 protein, human; D005169:Factor VIII