Changes in proteinase 3 anti-neutrophil cytoplasm autoantibody levels in early systemic granulomatosis with polyangiitis (Wegener's) may reflect treatment rather than disease activity
N. Rasmussen, A. Salmela, A. Ekstrand, K. De Groot, G. Gregorini, J.W. Cohen Tervaert, W.L. Gross, A. Wiik, D.R.W. Jayne, 1 On Behalf Of The European Vasculitis Study Group (euvas)
2013 Vol.31, N°1 ,Suppl.75
PI 0038, PF 0044
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PMID: 23380137 [PubMed]
Accepted : 03/12/2012
In Press: 01/02/2013
To investigate the nature of the relationship between proteinase 3 anti-neutrophil cytoplasm autoantibody (PR3-ANCA) and relapse in patients with early systemic granulomatosis with polyangiitis (Wegener`s) (GPA).
Clinical data from 16 relapsing and 12 non-relapsing patients with early systemic GPA from a randomised clinical trial were correlated to monthly PR3-ANCA values over 18 months. Each sample was examined using 9 different enzyme-linked immunosorbent assays (ELISAs) to ensure reliability of ANCA results. PR3-ANCA peaks were identified by the highest sum of logarithmic transformation values from all assays in samples after remission.
A PR3-ANCA peak was identified in all relapsing and non-relapsing patients and coincided with relapse in all 14 evaluable relapsing patients. The monthly increment before the peak, however, was similar in relapsing and non-relapsing patients in all assays. Increments from remission to peak were higher in relapsing patients in 2/9 assays. PR3-ANCA values at entry and peak PR3-ANCA values were higher in relapsing patients in 3/9 and 2/9 assays, respectively. However, large overlaps of PR3-ANCA values prevented a distinction between relapsing and non-relapsing patients. The median time to reach peak values was 14 months in relapsing and 12 months in non-relapsing patients with scheduled termination of treatment at 12 months.
The predictive value for relapses of PR3-ANCA determinations confirm and extend previous reports. Although all relapses were related to PR3-ANCA increases, reduction or withdrawal of immunosuppression without relapse was also related to increases and may explain the lack of predictive value of sequential PR3-ANCA determinations.