Restricted myeloperoxidase epitopes drive the adaptive immune response in MPO-ANCA vasculitis.
J Autoimmun
; 106: 102306, 2020 01.
Article
in En
| MEDLINE
| ID: mdl-31383567
ABSTRACT
BACKGROUND:
Treatment of autoimmune diseases has relied on broad immunosuppression. Knowledge of specific interactions between human leukocyte antigen (HLA), the autoantigen, and effector immune cells, provides the foundation for antigen-specific therapies. These studies investigated the role of HLA, specific myeloperoxidase (MPO) epitopes, CD4+ T cells, and ANCA specificity in shaping the immune response in patients with anti-neutrophil cytoplasmic autoantibody (ANCA) vasculitis.METHODS:
HLA sequence-based typing identified enriched alleles in our patient population (HLA-DPB1*0401 and HLA-DRB4*0101), while in silico and in vitro binding studies confirmed binding between HLA and specific MPO epitopes. Class II tetramers with MPO peptides were utilized to detect autoreactive CD4+ T cells. TCR sequencing was performed to determine the clonality of T cell populations. Longitudinal peptide ELISAs assessed the temporal nature of anti-MPO447-461 antibodies. Solvent accessibility combined with chemical modification determined the buried regions of MPO.RESULTS:
We identified a restricted region of MPO that was recognized by both CD4+ T cells and ANCA. The autoreactive T cell population contained CD4+CD25intermediateCD45RO+ memory T cells and secreted IL-17A. T cell receptor (TCR) sequencing demonstrated that autoreactive CD4+ T cells had significantly less TCR diversity when compared to naïve and memory T cells, indicating clonal expansion. The anti-MPO447-461 autoantibody response was detectable at onset of disease in some patients and correlated with disease activity in others. This region of MPO that is targeted by both T cells and antibodies is not accessible to solvent or chemical modification, indicating these epitopes are buried.CONCLUSIONS:
These observations reveal interactions between restricted MPO epitopes and the adaptive immune system within ANCA vasculitis that may inform new antigen-specific therapies in autoimmune disease while providing insight into immunopathogenesis.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Vasculitis
/
Peroxidase
/
Antibodies, Antineutrophil Cytoplasmic
/
Adaptive Immunity
/
Epitopes
Type of study:
Observational_studies
Limits:
Animals
/
Humans
Language:
En
Journal:
J Autoimmun
Journal subject:
ALERGIA E IMUNOLOGIA
Year:
2020
Document type:
Article