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The IgG2 Isotype of Anti–Transcription Intermediary Factor 1γ Autoantibodies Is a Biomarker of Cancer and Mortality in Adult Dermatomyositis
Author(s) -
Aussy Audrey,
Fréret Manuel,
Gallay Laure,
Bessis Didier,
Vincent Thierry,
Jullien Denis,
Drouot Laurent,
Jouen Fabienne,
Joly Pascal,
Marie Isabelle,
Meyer Alain,
Sibilia Jean,
BaderMeunier Brigitte,
Hachulla Eric,
Hamidou Mohammed,
Huë Sophie,
Charuel JeanLuc,
Fabien Nicole,
Viailly PierreJulien,
Allenbach Yves,
Benveniste Olivier,
Cordel Nadège,
Boyer Olivier
Publication year - 2019
Publication title -
arthritis and rheumatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.106
H-Index - 314
eISSN - 2326-5205
pISSN - 2326-5191
DOI - 10.1002/art.40895
Subject(s) - medicine , dermatomyositis , autoantibody , cancer , oncology , proportional hazards model , hazard ratio , univariate analysis , gastroenterology , antibody , immunology , multivariate analysis , confidence interval
Objective Anti–transcription intermediary factor 1γ (anti‐ TIF 1γ) antibodies are the main predictors of cancer in dermatomyositis ( DM ). Yet, a substantial proportion of anti‐ TIF 1γ–positive DM patients do not develop cancer. This study was undertaken to identify biomarkers to better evaluate the risk of cancer and mortality in DM . Methods This multicenter study was conducted in adult anti‐ TIF 1γ–positive DM patients from August 2013 to August 2017. Anti‐ TIF 1γ autoantibody levels and IgG subclasses were identified using a newly developed quantitative immunoassay. Age, sex, DM signs and activity, malignancy, and creatine kinase ( CK ) level were recorded. Risk factors were determined by univariate and multivariate analysis according to a Cox proportional hazards regression model. Results Among the 51 adult patients enrolled (mean ± SD age 61 ± 17 years; ratio of men to women 0.65), 40 (78%) had cancer and 21 (41%) died, with a mean ± SD survival time of 10 ± 6 months. Detection of anti‐ TIF 1γ IgG2 was significantly associated with mortality ( P = 0.0011) and occurrence of cancer during follow‐up ( P < 0.0001), with a 100% positive predictive value for cancer when the mean fluorescence intensity of anti‐ TIF 1γ IgG2 was >385. None of the patients developed cancer after 24 months of follow‐up. Univariate survival analyses showed that mortality was also associated with age >60 years ( P = 0.0003), active DM ( P = 0.0042), cancer ( P = 0.0031), male sex ( P = 0.011), and CK level >1,084 units/liter ( P = 0.005). Multivariate analysis revealed that age >60 years ( P = 0.015) and the presence of anti‐ TIF 1γ IgG2 ( P = 0.048) were independently associated with mortality. Conclusion Our findings indicate that anti‐ TIF 1γ IgG2 is a potential new biomarker of cancer that should be helpful in identifying the risk of mortality in anti‐ TIF 1γ–positive DM patients.