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- Sandin, Charlotta, et al.
(author)
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IgA- and SIgA anti-PR3 antibodies in serum versus organ involvement and disease activity in PR3-ANCA associated vasculitis.
- 2016
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In: Clinical and Experimental Immunology. - : Wiley-Blackwell. - 0009-9104 .- 1365-2249. ; 184:2, s. 208-215
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Journal article (peer-reviewed)abstract
- Circulating IgA class anti-neutrophil cytoplasm antibodies (ANCA) directed against proteinase 3 (PR3) have been reported in ANCA-associated vasculitis (AAV) with mucosal involvement. However, secretory IgA (SIgA) PR3-ANCA has not been reported previously. In this study we compared serum levels of SIgA PR3-ANCA and IgA PR3-ANCA with IgG PR3-ANCA in relation to disease characteristics. Among 73 patients with AAV and PR3-ANCA at diagnosis, 84% tested positive for IgG PR3-ANCA, 47% for IgA-ANCA and 36% for SIgA PR3-ANCA at the time of sampling for the present study. IgA and IgG PR3-ANCA were similarly represented among patients with different organ manifestations, i.e. upper airway, lung or kidney at time of sampling. However, SIgA PR3-ANCA was significantly less represented among patients with upper airway involvement. During active disease, the proportions of IgA PR3-ANCA and SIgA PR3-ANCA positive patients were significantly higher as compared to inactive disease. Eight patients were prospectively sampled during 24 months from onset of active disease. In these patients, IgA PR3-ANCA and SIgA PR3-ANCA more often turned negative after remission induction as compared to IgG PR3-ANCA. Our findings suggest that serum IgA PR3-ANCA and SIgA PR3-ANCA are more closely related to disease activity in AAV as compared to IgG PR3-ANCA. Further studies are required to reveal if this has implications for disease activity monitoring. The mean number of PR3-ANCA isotypes increased along with disease activity, suggesting a global B-cell activation during active disease. This article is protected by copyright. All rights reserved.
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