Macro CK type 1 as a marker for autoimmunity in coronary heart disease

Area of Science:

• Clinical Chemistry
• Immunology
• Cardiology

Background:

• Immunoglobulin bound creatine kinase (macro CK type 1) is a complex that can interfere with diagnostic assays.
• Its prevalence and clinical significance, especially in cardiac patients, require further investigation.

Purpose of the Study:

• To determine the prevalence of macro CK type 1 in a general hospital population and in cardiac patients.
• To investigate the correlation between macro CK type 1 and coronary angiography findings.
• To assess the impact of macro CK type 1 on creatine kinase MB (CK MB) assays.

Main Methods:

• Prevalence study in 3000 hospital patients and 556 cardiac patients undergoing coronary angiography.
• Analysis of macro CK type 1 activity.
• Evaluation of CK MB results from ion-exchange and immuno-inhibition techniques in macro CK type 1 positive patients.

Main Results:

• Macro CK type 1 prevalence was 4.3% in the general hospital population, increasing with age.
• Prevalence was higher (13.8%) in cardiac patients.
• No significant correlation was found between macro CK type 1 activity and coronary angiography findings.
• CK MB results were falsely positive in macro CK type 1 positive patients.

Conclusions:

• Macro CK type 1 is a clinically relevant finding, particularly in older patients and those with cardiac conditions.
• Macro CK type 1 can cause diagnostic errors in CK MB testing.
• The study suggests macro CK type 1 is an antigen-antibody complex against CK BB, potentially originating from the vascular wall.