Changes in proteinase 3 anti-neutrophil cytoplasm autoantibody levels in early systemic granulomatosis with polyangiitis (Wegener's) may reflect treatment rather than disease activity

• Published in: Clinical and experimental rheumatology Vol. 31; no. 1 Suppl 75; pp. S38 - S44
• Main Authors: Rasmussen, N, Salmela, A, Ekstrand, A, de Groot, K, Gregorini, G, Cohen Tervaert, J W, Gross, W L, Wiik, A, Jayne, D R W
• Format: Journal Article
• Language: English
• Published: Italy 01-01-2013
• Subjects: Adolescent; Adult; Aged; Antibodies, Antineutrophil Cytoplasmic - blood; Biomarkers - blood; Enzyme-Linked Immunosorbent Assay; Female; Granulomatosis with Polyangiitis - blood; Granulomatosis with Polyangiitis - diagnosis; Granulomatosis with Polyangiitis - drug therapy; Granulomatosis with Polyangiitis - immunology; Humans; Immunosuppressive Agents - therapeutic use; Male; Middle Aged; Myeloblastin - immunology; Predictive Value of Tests; Prospective Studies; Recurrence; Remission Induction; Severity of Illness Index; Time Factors; Treatment Outcome; Young Adult
• ISSN: 0392-856X

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.