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Endomyocardial fibrosis and eosinophilia
Insights
Eosinophil counts in African endomyocardial fibrosis patients were higher but comparable to controls. Parasitic infections were common but poorly correlated with eosinophilia, suggesting other causes for this tropical heart disease.
Area of Science:
- Cardiology
- Tropical Medicine
- Immunology
Background:
- Endomyocardial fibrosis (EMF) is a tropical heart disease with unclear etiology.
- Eosinophilia and parasitic infections are prevalent in tropical regions, raising questions about their role in EMF.
Purpose of the Study:
- To investigate the relationship between absolute eosinophil counts, parasitic infections, and endomyocardial fibrosis in African patients.
- To differentiate African EMF from other eosinophilic cardiac conditions.
Main Methods:
- Assessed absolute eosinophil counts in 15 African patients with endomyocardial fibrosis.
- Reviewed literature on potential etiological factors including genetic, environmental, and immunological aspects.
Main Results:
- Mean eosinophil counts were higher in EMF patients than reported normals, but the absolute range was comparable.
- A high prevalence of parasitic infections (malaria, hookworm, strongyloides) was observed, but correlation with eosinophilia was poor.
- African EMF appears distinct from Löffler's endocarditis and other eosinophilic cardiac conditions.
Conclusions:
- Parasitic infections and eosinophilia are common in the tropics but do not appear to be the primary drivers of African endomyocardial fibrosis.
- Genetic, environmental, and immunological factors are likely crucial in the causation of endomyocardial fibrosis in Uganda.
Abstract:
Absolute eosinophil counts were assessed in 15 African patients with proven endomyocardial fibrosis. Though the mean eosinophil count in patients with endomyocardial fibrosis was higher compared with the normals reported from Kampala (1-13 vs 0.72X10(9)/1), the absolute range was comparable. A high percentage of patients with endomyocardial fibrosis had malarial parasites, high malarial antibody titres, hookworms, or strongyloides, but the correlation of eosinophilia to various parasitic infections was poor. Both eosinophilia and parasitic infections are common in the tropics and they effect patients with endomyocardial fibrosis no more than the population at large. Other aetiological factors, genetic, environmental, and immunological, are felt to be important in the causation of endomyocardial fibrosis in Uganda and evidence for this is reviewed. Though there is a similarity in pathological features, African endomyocardial fibrosis is a distinct entity from Löffler's endocarditis and cardiac lesions seen in eosinophilic leukaemia or reactive eosinophilia. There is no hard evidence to suggest that African endomyocardial fibrosis is a variant of Löffler's endocarditis caused by parasitic infections via eosinophilia.