Slide 1: Cystic fibrosis (CF) can cause elevations in which auto-antibody associated with vasculitis?

Slide 2: Answer: p-ANCA! Up to 28% of all CF patients show p-ANCA positivity. Associated factors include: low BMI, low FEV1, infection with Pseudomonas aeruginosa.

Slide 3: Importantly, pulmonary infections increase the levels of BPI (bactericidal/permeability-increasing protein), which helps fight off infection. However, patients can also develop autoantibodies to BPI, measured clinically as p-ANCA.

Slide 4: In one study of 40 CF patients with p-ANCA positivity, nondeveloped signs or symptoms of vasculitis (eg MPA or EGPA). Instead, the p-ANCA was associated with poorer respiratory prognosis.