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Updated: Jan 13, 2026
Flow Cytometry-Based Quantification and Analysis of Myocardial B-Cells
Published on: August 17, 2022
Immunohistological evidence for a chronic intramyocardial inflammatory process in dilated cardiomyopathy
U Kühl1, M Noutsias, B Seeberg
1Benjamin Franklin Hospital, Frei University of Berlin, Germany.
Insights
Nearly half of dilated cardiomyopathy (DCM) patients show signs of chronic inflammation and immune activation in cardiac biopsies. Immunohistochemistry is crucial for diagnosing myocarditis in these cases.
Area of Science:
- Cardiovascular Pathology
- Immunohistochemistry
- Autoimmune Diseases
Background:
- Dilated cardiomyopathy (DCM) is a clinical diagnosis often associated with myocardial damage.
- The presence and significance of chronic inflammation in DCM remain areas of active investigation.
- Conventional histology may underestimate inflammatory processes in cardiac biopsies.
Purpose of the Study:
- To investigate the presence of chronic inflammatory processes in cardiac biopsies from patients diagnosed with DCM using immunohistochemical analysis.
- To determine if immunohistochemistry can enhance the diagnostic sensitivity for myocarditis in DCM patients.
Main Methods:
- Comparative case control study utilizing cardiac biopsies.
- Analysis of 170 DCM patients and 85 control patients with other cardiac diseases.
- Immunohistochemical staining to identify T lymphocytes and assess immune activation (MHC expression, adhesion molecules).
Main Results:
- 48% of DCM patients exhibited T lymphocytes in the myocardium, with significant densities in many.
- 89% of those with T lymphocytes showed interstitial and endothelial immune activation (MHC expression).
- Lymphocyte density correlated with increased expression of adhesion molecules and MHC antigens.
Conclusions:
- A significant percentage of DCM patients exhibit increased T lymphocyte density and immune activation in cardiac biopsies.
- Evidence suggests an active chronic autoimmune process within the myocardium in a substantial portion of DCM patients.
- Immunohistochemical analysis is essential for improving the diagnostic accuracy of cardiac biopsies for myocarditis in DCM.
Objective:
To determine whether immunohistochemical analysis of cardiac biopsies from patients presenting clinically as dilated cardiomyopathy (DCM) show a chronic inflammatory process.
Design:
Comparative case control study.
Setting:
Tertiary referral centre.
Patients:
Biopsies from 170 patients with DCM and 85 control patients with other cardiac diseases.
Results:
Nine patients had sufficient interstitial inflammatory cells to be called borderline myocarditis on conventional histology, leaving 161 patients with DCM. In 78 patients with DCM (48%) there were T lymphocytes in the myocardium. In 48 (62%) of these 78 T lymphocyte densities were in the range 2-14 per high power field (HPF), equivalent to 7-50 per mm2 of tissue. In 43 (89%) interstitial and endothelial immune activation was demonstrated by MHC expression. In 30 patients with T cell counts in the range 1.5-2.0 per HPF, 80% also showed endothelial activation. Lymphocyte density correlated with increased expression of MHC class I and II antigens and the adhesion molecules ICAM, VCAM, ELAM, LFA-3, and GMP140. In all control biopsies the T lymphocyte density was less than 1.0 per HPF (less than 2-5 per mm2 of tissue).
Conclusions:
Nearly half the patients with DCM had increased T lymphocyte density and immune activation of endothelial and interstitial cells in their cardiac biopsies. A chronic autoimmune process is still active within the myocardium in a significant percentage of patients with DCM. Immunohistochemical analysis of cardiac biopsies will enhance the sensitivity of cardiac biopsy and is essential for the diagnosis of myocarditis.
