Relationship between serum IgG4 concentrations and atherosclerotic coronary plaques assessed by computed tomographic angiography

Background: Immunoglobulin G4 (IgG4)-related immuno-inflammation has been suggested to affect the development of coronary artery atherosclerosis. The aim of this study was to analyze the association of serum IgG4 concentrations with calcified and non-calcified coronary plaques.

Methods: Serum IgG4 concentrations were measured in 263 patients who underwent 320-slice coronary computed tomographic (CT) angiography. Vulnerable coronary plaques were evaluated for CT plaque characteristics, including low-density plaque (LDP), positive remodeling, and spotty calcification.

Results: Serum concentrations of IgG4 were significantly higher in patients with non-calcified plaque (NCP) than in those without (32.2mg/dL vs. 23.7mg/dL, p=0.029). By contrast, the median serum IgG4 concentrations in patients with and without calcified plaque were 31.2mg/dL and 26.2mg/dL, respectively (p=0.107). Serum IgG4 concentrations were significantly elevated in patients with LDP (33.5mg/dL vs. 26.9mg/dL, p=0.002) and in those with positive remodeling (31.4mg/dL vs. 28.4mg/dL, p=0.039) than in those without. Patients with spotty calcification also had significantly higher serum IgG4 concentrations than those without (32.1mg/dL vs. 24.9mg/dL, p=0.049). In age- and gender-adjusted logistic regression analysis, the highest IgG4 quartile (≥56.7mg/dL) was significantly associated with LDP with an odds ratio of 2.49 (95% CI, 1.15-5.36, p=0.020).

Conclusions: Serum IgG4 concentrations were significantly associated with NCP, especially with LDP, suggesting that IgG4-related immuno-inflammation may play a role in coronary plaque vulnerability.