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IgM colocalises with complement and C reactive protein in infarcted human myocardium
P A J Krijnen1, C Ciurana, T Cramer
1Department of Pathology, VU Medical Centre, Amsterdam, De Boelelaan 1117, 1007 MB The Netherlands. paj.krijnen@vumc.nl
Journal of Clinical Pathology
|March 26, 2005
Summary
Immunoglobulin M (IgM) and C-reactive protein (CRP) target complement locally to damaged heart cells after myocardial infarction. Their deposition patterns suggest they recognize similar targets, but their roles in complement activation vary between patients.
Area of Science:
- Cardiovascular Science
- Immunology
- Pathology
Background:
- Ischaemia/reperfusion (I/R) injury following acute myocardial infarction (AMI) involves complement system activation.
- C-reactive protein (CRP) plays a role in this complement activation pathway.
Purpose of the Study:
- To investigate the potential role of Immunoglobulin M (IgM) in complement activation within the infarcted human myocardium.
- To analyze the localization and deposition patterns of IgM in comparison to CRP and complement factors in AMI.
Main Methods:
- Immunochemical analysis of heart specimens from 59 patients who died from AMI.
- Staining of myocardial tissue for IgM, C3d, C5b-9 (membrane attack complex), and CRP.
Main Results:
- IgM deposits were observed in jeopardized cardiomyocytes within 1-5 days post-infarction.
- IgM deposition patterns closely resembled those of CRP and complement factors.
- Significant variation in the relative staining intensities of IgM and CRP was noted among patients.
Conclusions:
- IgM, similar to CRP, locally targets complement activation on jeopardized cardiomyocytes in the human heart post-AMI.
- IgM and CRP appear to recognize similar epitopes in the ischaemic heart.
- The relative contribution of IgM and CRP to complement activation in the ischaemic myocardium varies individually.