Antineutrophil cytoplasmic antibody-positive conversion and microscopic polyangiitis development in patients with idiopathic pulmonary fibrosis

Abstract

BackgroundIncreasing evidence indicates that antineutrophil cytoplasmic antibody (ANCA)-positive conversion occurs in patients initially diagnosed with idiopathic pulmonary fibrosis (IPF) and as a result, some of these patients develop microscopic polyangiitis (MPA). However, the incidence density of these patients is not well known.ObjectivesTo explore the incidence of ANCA-positive conversion and development of MPA during the disease course in patients with IPF and to evaluate whether corticosteroid therapy reduces MPA development in patients with IPF with myeloperoxidase (MPO)-ANCA positivity at diagnosis or who later acquire MPO-ANCA positivity.MethodsWe retrospectively analysed the medical records of 504 Asian patients with IPF treated at our institution in Saitama, Japan.ResultsOf the 504 patients with IPF, 20 (4.0%) had MPO-ANCA and 16 (3.2%) had PR-3-ANCA when first evaluated. In 264 of 504 patients with IPF, ANCA was measured repeatedly and seroconversion to MPO-ANCA and PR3-ANCA occurred in 15 (5.7%) and 14 (5.3%) patients, respectively, and 9 of 35 patients who were either MPO-ANCA positive at IPF diagnosis or who subsequently seroconverted developed MPA. None of the nine patients who developed MPA had been previously treated with steroids. The incidence of MPA tended to be lower in patients treated than not treated with corticosteroids although this was not statistically significant.ConclusionsSome patients with IPF with MPO-ANCA positivity at IPF diagnosis or with MPO-ANCA-positive conversion during follow-up developed MPA. Clinical trials to determine whether corticosteroid therapy can reduce MPA development and prolong survival in MPO-ANCA-positive patients with IPF should be considered.

Interstital lung disease in ANCA vasculitis

“…On the other hand, prevalence of ANCA in cohorts of individuals who initially presented with isolated pulmonary fibrosis ranges between 4%–36% for MPO-ANCA and 2–4% for PR3-ANCA [13,16,27,46,48,50,56–59]. During follow-up, 5–10% of ANCA negative patients developed autoantibodies against MPO or PR3 (incidence of 12 cases per 1000 person years) [13,16,46,50,58].…”

Testing for antineutrophil cytoplasmic antibodies (ANCAs) in patients with systemic vasculitides and other diseases

“…Seropositive patients presented more commonly with a subacute form of infective endocarditis leading to multiple valve involvement and a more frequent renal impairment 3. Recent evidence indicates that a proportion of patients with idiopathic pulmonary fibrosis who were MPO-ANCA positive at diagnosis or who subsequently seroconverted can develop MPA 7. The incidence of MPA tended to be lower in patients treated than not treated with corticosteroids though the difference did not reach statistical significance.…”

Muscle weakness as a presenting symptom in ANCA-associated vasculitis

“…Another case series with pulmonary fibrosis in AAV also described that 4 (33%) of 12 cases had muscle involvement (7). Moreover, cases of idiopathic pulmonary fibrosis with MPO-ANCA are likely to show the presence of rheumatoid factor, compared with those without (8,9). Accordingly, muscle symptom in AAV may likely be associated with pulmonary fibrosis and rheumatoid factor, as also seen in the previous cases (Table 1).…”