Background: IgG4 is a type of serum protein which constitutes a subgroup of immunoglobulin superfamily of proteins and is assumed to play a central role in certain immune mediated conditions defined as IgG4-related disease. There are paucity of data regarding association of IgG4 and cardiovascular disease.
Aim: To investigate the association between serum concentrations of IgG4 and dilated cardiomyopathy (DCM).
Methods and patients: Patients with idiopathic DCM (LVEF < 40% in whom CAD was excluded) and age-, LVEF- , NYHA FC – matched patients with ischemic DCM (LVEF < 40% and proved CAD) were included in this study. Serum concentrations of IgG4 were measured by turbidimetry.
Results: Serum levels of IgG4 of 54 patients with idiopathic DCM (mean age 57±12.3 years, 65% male, mean LVEF 33.0±8.6%) were compared with 44 matched patients with ischemic DCM. A group of 46 healthy subjects was used as controls in order to define normal ranges of IgG4. In patients with ischemic DCM, the serum concentrations of IgG4 (mean±SE) were significantly higher than corresponding values in normal controls (89.77±10.15 vs 50.28±4.24 mg/dl, p<0.001). There was a clear trend towards higher serum levels of IgG4 in patients with idiopathic DCM compared with normal controls (67.34±8.16 vs 50.28±4.24 mg/dL, p=0.08) and in patients with ischemic DCM compared with patients with idiopathic DCM (89.77±10.15 vs 67.34±8.16 mg/dL, p=0.08).
Conclusions: Increased serum concentrations of IgG4 were associated with patients with DCM especially with ischemic DCM suggesting the possible role of IgG4-related immune-inflammation in development of this disease. Larger studies are warrant to investigate the link between IgG4 and dilated cardiomyopathy.
