ANCA linked to interstitial lung disease, pulmonary embolism in systemic sclerosis
Anti-neutrophil cytoplasmic antibodies are linked to an increased prevalence of interstitial lung disease and pulmonary embolism in systemic sclerosis, according to data published in Arthritis Research & Therapy.
“The clinical significance of ANCA in [systemic sclerosis (SSc)] patients who do not manifest [ANCA-associated vasculitis] is controversial. An association between ANCA in SSc and [interstitial lung disease] has been suggested,” Mandana Nikpour, PhD, MBBS, FRACP, FRCPA, of the University of Melbourne, Australia, and colleagues wrote. “However, this has not been consistently reported in all case series. It has also been suggested that ANCA in SSc patients may indicate an inflammatory component to the illness and that ANCA should be treated as a ‘red flag,’ prompting a thorough investigation and follow-up.”
To analyze the prevalence of ANCA in patients with SSc, and to determine the association between ANCA and the clinical characteristics of SSc, its treatments and mortality, Nikpour and colleagues recruited 1,303 patients from the Australian Scleroderma Cohort Study. According to the researchers, this cohort had been a multicenter study of risk and prognostic factors among patients with SSc at five centers.
Nikpour and colleagues included cohort participants recruited between Jan. 1, 2007, and May 23, 2016, who met the 2013 American College of Rheumatology/EULAR criteria for SSc. Patients with mixed connective-tissue disease were excluded. The researchers defined “ANCA-positive” as the presence of at least one of the following: Cytoplasmic ANCA (c-ANCA), perinuclear ANCA (p-ANCA), atypical ANCA, anti-myeloperoxidase (anti-MPO) or anti-proteinase-3 (anti-PR3). Logistic or linear regression were used to determine associations of demographic and clinical features with ANCA.
According to the researchers, 116 of the 1,303 included participants were ANCA-positive. Among these patients, 13.8% were anti-PR3, while 11.2% were anti-MPO. In addition, just three patients who were ANCA-positive had ANCA-associated vasculitis. Anti-Scl-70 antibodies were present in 25% of those who were ANCA-positive, compared with 12.8% in patients who were ANCA-negative (P <.001), as well as in 38.5% of those who were anti-MPO–positive, compared with 13.6% in the anti-MPO–negative group (P=.006). Anti-Scl-70 antibodies were also present in 44.4% of those who were anti-PR3–positive, compared to 13.4% of those in the anti-PR3–negative group (P<.001).
The prevalence of interstitial lung disease was 44.8% among patients identified as ANCA-positive, and 21.8% in patients who were ANCA-negative (P<0.001). Patients who were anti-PR3–positive also demonstrated a higher prevalence for interstitial lung disease, with 50%, compared with 23.4% in the anti-PR3–negative group (P=.009).
Prevalence rates for pulmonary embolism were 8.6% for patients who were ANCA-positive, compared with 3% for the ANCA-negative group (P =.002), and 16.7% among patients who were anti-PR3–positive, compared with 3.3% in the anti-PR3–negative group (P=.022). These associations remained following multivariable analysis.
“This study reveals a significant association between ANCA in SSc and [interstitial lung disease], pulmonary embolism, synovitis and overlap syndrome with other connective tissue diseases,” Nikpour and colleagues wrote. “Patients who are ANCA-positive have increased mortality, independent of sex or age at diagnosis. These findings suggest that ANCA should be tested at baseline in SSc patients as it is associated with a worse prognosis and necessitates vigilant monitoring and follow-up.” – by Jason Laday
Disclosure: Nikpour reports no relevant financial disclosures. Please see the study for all other relevant financial disclosures.