Prevalence and clinical significance of circulating autoantibodies in idiopathic pulmonary fibrosis

Abstract

Background: The clinical significance of circulating autoantibodies in idiopathic pulmonary fibrosis is unclear. The objective of this study was to determine the frequency and clinical significance of circulating autoantibodies in idiopathic pulmonary fibrosis. Methods: We measured an extensive panel of autoantibodies (including rheumatoid factor, anti-cyclic citrullinated peptide, and anti-nuclear antibodies by immunofluorescence) associated with connective tissue disease or vasculitis in a cohort of well-characterized patients with idiopathic pulmonary fibrosis (n = 67). The prevalence of circulating autoantibodies was compared between idiopathic pulmonary fibrosis patients and healthy controls (n = 52). We compared the clinical characteristics of patients with and without circulating autoantibodies, and analyzed the relationship between autoantibody positivity and transplant-free survival time. Results: Positive autoantibodies were found in 22% of patients with IPF and 21% of healthy controls. There were no differences in the types of autoantibodies found between patients with idiopathic pulmonary fibrosis and healthy controls. Among patients with idiopathic pulmonary fibrosis, there were no significant differences in clinical characteristics between those with and without circulating autoantibodies. The presence of circulating autoantibodies was associated with longer transplant-free survival time on adjusted analysis, however the significance varied depending on which statistical model was used (HR 0.22-0.47, p value 0.02-0.17). Conclusions: The frequency of circulating autoantibodies in patients with idiopathic pulmonary fibrosis is no different compared to healthy controls, but may be associated with longer survival.© 2012 Elsevier Ltd. All rights reserved

Significance of connective tissue diseases features in pulmonary fibrosis

“…Among patients with IPF, no differences were found in clinical, functional or imaging characteristics between those with and without auto-antibodies. When adjusted for age, sex, smoking and forced vital capacity, circulating antibodies (antinuclear antibodies with titre o1:320 or rheumatoid factor o60 UI?mL -1 ) seem to be associated with longer transplant-free survival time [48]. Overall, these observations suggest that the frequency of circulating autoantibodies in patients with IPF is similar to that of healthy controls, with unclear impact on survival.…”

“…As compared to IPF patients with negative autoimmune biology, those with auto-antibodies are more likely to exhibit ground-glass attenuation, have more significant honeycombing and a higher extent of ILD at HRCT but similar survival [7]. Similarly, LEE et al [48] tested 67 patients with IPF and 52 healthy controls for the presence of an extensive panel of auto-antibodies and found no difference in the frequency or type of antibodies between IPF and control subjects (22% versus 21%), probably reflecting auto-antibodies of unknown significance in an ageing population rather than genuine UCTD (although long-term follow-up was not available). Among patients with IPF, no differences were found in clinical, functional or imaging characteristics between those with and without auto-antibodies.…”

Interstitial lung disease

“…The role of autoimmunity is better delineated in other ILDs, such as idiopathic NSIP [88], but it is still unclear in IPF. LEE et al [89] compared 67 IPF patients to 52 healthy controls and found positive autoantibodies in 22% of IPF patients and 21% of healthy controls, without significant differences in the types of autoantibodies or clinical characteristics between IPF, with and without circulating autoantibodies. The presence of circulating autoantibodies was associated with longer TFS time on adjusted analysis; however, the significance varied depending on which statistical model was used (HR 0.22-0.47, p-value 0.02-0.17).…”

Differential diagnosis of usual interstitial pneumonia: when is it truly idiopathic?

“…However, in our case there were no clinical, serological or pathological findings suggestive of an underlying systemic disease. Patients with IPF may have mildly positive anti-nuclear antibody and/or rheumatoid factor serology, although their frequency does not appear to differ from healthy, age-matched controls [11]. Finally, despite his exposure to amiodarone, we confidently excluded that our patient had a drug-induced ILD based on distinctive radiological, BAL and pathological findings.…”