Detection of Anti-Pentraxin-3 Autoantibodies in ANCA-Associated Vasculitis
Abstract
Objectives
Pentraxin 3 (PTX3), in common with myeloperoxidase and proteinase 3, is stored in human
neutrophil granules and is expressed on apoptotic neutrophil surface. We therefore investigated
the presence of anti-PTX3 autoantibodies (aAbs) in the sera of antineutrophil cytoplasmic
antibodies (ANCA)-associated vasculitis (AAV) patients.
Methods
Presence of anti-PTX3 autoantibodies was analysed by a specific enzyme-linked immunosorbent
assay in sera from 150 patients with microscopic polyangiitis (MPA), granulomatosis
with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA), and
in sera of 227 healthy subjects (HS), 40 systemic sclerosis (SSc) patients, and 25 giant cell
arteritis patients (GCA). Using indirect immunofluorescence on fixed human neutrophils, we
also analyzed the staining pattern associated with the presence of anti-PTX3 aAbs.
Results
Anti-PTX3 aAbs were detected in 56 of 150 (37.3%) of the AAV patients (versus 12 of 227
(5.3%) of HS, p<0.001) and, interestingly, in 7 of 14 MPO and PR3 ANCA negative AAV
patients. Moreover, by indirect immunofluorescence on fixed neutrophils, anti-PTX3 aAbs
gave rise to a specific cytoplasmic fluorescence pattern distinct from the classical cytoplasmic
(c-ANCA), perinuclear (p-ANCA), and atypical (a-ANCA) pattern. Anti-PTX3 aAbs
levels were higher in patients with active AAV as compared to patients with inactive
disease.
Conclusion
Our work suggests that PTX3 is as a novel ANCA antigen. Anti-PTX3 aAbs appear thus as
a promising novel biomarker in the diagnosis of AAV, including in patients without detectable
MPO and PR3 ANCA.
Domains
Cancer
Origin : Files produced by the author(s)
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