{'fraction_non_alphanumeric': 0.050475059382422804, 'fraction_numerical': 0.04928741092636579, 'mean_word_length': 4.933098591549296, 'pattern_counts': {'":': 0, '<': 3, '<?xml version=': 0, '>': 2, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Relation between asymptomatic proteinase 3 antibodies and future granulomatosis with polyangiitis.

BACKGROUND AND OBJECTIVES
The subclinical pathogenesis of granulomatosis with polyangiitis (GPA) has not been completely elucidated. Proteinase 3 (PR3) antibodies are strongly associated with GPA, but have not been evaluated before disease presentation.


DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS
This was a retrospective case-control serum bank study in which PR3 antibodies and C-reactive protein (CRP) in up to three longitudinal serum samples for 27 GPA patients before diagnosis (1 day-19 years) were compared with 27 controls whose serum samples were matched for age, sex, and race. This study analyzed all patients with American College of Rheumatology criteria-confirmed disease identified in the Department of Defense electronic medical records between 1990 and 2008.


RESULTS
A greater percentage of GPA patients had at least one elevated PR3 antibody level (≥6 U/ml) as well as at least one detectable PR3 antibody level (>1 U/ml) before diagnosis compared with matching controls (63% [17 of 27] versus 0% [0 of 27], P<0.001; and 85% [23 of 27] versus 4% [1 of 27], P<0.001, respectively). A greater percentage of GPA patients had a >1 U/ml per year rate of increase in PR3 antibody level compared with matching controls (62% [21 of 26] versus 0% [0 of 26], P<0.001). PR3 antibody more frequently became elevated before CRP (67% [12 of 18] versus 33% [6 of 18], P=0.04).


CONCLUSIONS
Subclinical PR3 antibody presence, trajectory, and temporal relationship to CRP associates with the future diagnosis of GPA. This data set further elucidates the pathogenesis of GPA.