Prevalence of Elevated Serum IgG4 Level among Patients Diagnosed or Suspected with Cardiovascular Disorders
Nobukazu Ishizaka1, Yasunari Fujinaga2, Ryoto Hourai1
1Department of Cardiology, Osaka Medical College, Takatsuki, Osaka, Japan.
Insights
Elevated serum Immunoglobulin G4 (IgG4) levels are present in some cardiac patients. However, high IgG4 levels alone are not sufficient for diagnosing IgG4-related cardiovascular disease without further evidence.
Area of Science:
- Cardiology
- Immunology
- Rheumatology
Background:
- Immunoglobulin G4 (IgG4)-related disease involves elevated IgG4 levels and IgG4-positive plasma cell infiltration.
- Cardiovascular involvement in IgG4-related disease can worsen prognosis.
- Diagnosing IgG4-related cardiovascular lesions is challenging due to risks associated with tissue sampling.
Purpose of the Study:
- To examine serum IgG4 levels in patients within a cardiology department and those undergoing coronary angiography.
- To assess the diagnostic utility of elevated serum IgG4 levels for cardiovascular lesions.
Main Methods:
- Serum IgG4 levels were measured in 477 cardiology patients and 401 patients undergoing computed tomography coronary artery angiography.
- Prevalence of elevated serum IgG4 (≥135 mg/dL) was determined.
- Clinicopathological diagnosis was pursued for patients with elevated IgG4 levels.
Main Results:
- Elevated serum IgG4 levels were found in 4.8% of cardiology patients and 4.2% of angiography patients.
- Only two patients with elevated IgG4 levels received a clinicopathological diagnosis of IgG4-related disease.
- A significant number of cardiac patients showed high IgG4 levels without a confirmed IgG4-related disease diagnosis.
Conclusions:
- Elevated serum IgG4 levels are not uncommon in cardiac patients but do not confirm IgG4-related cardiovascular disease.
- Physicians should exercise caution when interpreting serum IgG4 levels for diagnosing cardiovascular lesions, especially without histopathological confirmation.
- Further investigation is needed to understand the implications of elevated IgG4 in cardiac patients without overt IgG4-related disease.
Abstract:
Immunoglobulin G4 (IgG4)-related disease, that is characterized by the elevation of circulating IgG4 level and the tissue-infiltration of IgG4-positive plasma cells, can target the cardiovascular tissue, although the diagnosis of IgG4-related cardiovascular lesion is not easy owing to the substantial risk for the tissue sampling. We herein examined the serum IgG4 levels among cardiac patients. In patients who were admitted to the cardiology department (n=477) and those who underwent computed tomography coronary artery angiography (n=401), elevated serum IgG4 level (≥135 mg/dL) was found 23 (4.8%) and 17 (4.2%), respectively. However, among those with elevated serum IgG4, only two patients could be clinicopathologically diagnosed with IgG4-related disease. Cardiovascular organ involvement may aggravate the prognosis of IgG4-related disease which in general not life-threatening. Considering that the non-negligible prevalence of high IgG4 level among cardiac patients who were not diagnosed with IgG4-related disease, however, physicians should not count too much on the serum IgG4 levels for the diagnosis of IgG4-related cardiovascular lesions, especially when histopathologic findings are not available, or when other-tissue involvement of IgG4-related disease is not apparent. (This is a translation of J Jpn Coll Angiol 2017; 57: 91-98.).
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