Clinical features and predictive value of serum inflammatory markers of perivascular involvement in immunoglobulin G4-related disease.

Vascular and/or perivascular involvements of sclerotic inflammation (perivasculitis) are a complication of immunoglobulin G4-related disease (IgG4-RD). We sought to examine clinical manifestations of perivasculitis by computed tomography (CT) in patients with elevated serum IgG4 levels, and then to evaluate some potential predictors of perivasculitis in definite IgG4-RD patients. From a database of patients with serum IgG4 measurements, we selected 81 patients with elevated serum IgG4 levels (≥135 mg/dl). Perivasculitis was defined radiologically as thickened contrast-enhanced rind surrounding the aorta and its major artery on CT imaging. We found 15 patients with perivasculitis; 10 patients in the definite (n = 37), four in the possible (n = 18), and one in the excluded (n = 26) IgG4-RD groups. Clinical predictors of perivasculitis were investigated in 34 untreated patients with definite IgG4-RD. Patients with perivasculitis (n = 10) had significantly higher age at diagnosis (74.2 ± 8.8 vs 63.5 ± 9.9 years, P = 0.006), higher levels of serum IgG4 (754 vs 292 mg/dl, P = 0.007) and C-reactive protein (CRP, 0.52 mg/dl vs 0.10 mg/dl, P = 0.001) than patients without perivasculitis (n = 24). The sensitivity and specificity of serum CRP ≥0.25 mg/dl for identifying perivasculitis in the definite IgG4-RD group were 100 and 71%, respectively (area under the receiver operating characteristic curve 0.863). Our results indicate that IgG4-related perivasculitis was associated with elevated levels of serum CRP and older age, and that CRP may be a useful marker for detecting perivascular involvement in IgG4-RD.