HLA antigen associations in hypertrophic cardiomyopathy

Human Leukocyte Antigens in Hypertrophic Cardiomyopathy Patients in South India

Hypertrophic cardiomyopathy is characterized by massive ventricular hypertrophy, reduced diastolic function, and excessive ventricular contraction. The human leukocyte antigens HLA-A, HLA-B, and HLA-DR were studied in 14 hypertrophic cardiomyopathy patients with left ventricular obstruction from South India. They were compared with 81 normal age- and sex-matched individuals from the same ethnic background. The human leucocyte antigens were identified using the standard serological assay with a longer incubation for DR antigens. The odds ratio, frequency, chi-squared value, p-value, etiological fraction, preventive fraction, and haplotype frequency estimates were calculated. The HLA-B51 and HLA-DR2 levels were significantly increased in hypertrophic cardiomyopathy patients compared to controls, whereas HLA-A19, HLA-B7, and HLA-DR4 were decreased when compared to the controls. It was noticed that haplotype B51-DR2-DQ3 was significantly associated with hypertrophic cardiomyopathy patients from South India. Hypertrophic cardiomyopathy may be associated with genes in the human leukocyte antigen region, and immunogenetic factors linked to human leukocyte antigens appear to play a major role in the pathogenesis.

HLA-DR3 antigen linkage in patients with hypertrophic obstructive cardiomyopathy

In order to investigate if genetic factors could be involved in the pathogenesis of hypertrophic obstructive cardiomyopathy, we determined HLA-A, HLA-B, HLA-C, and HLA-DR specificities in 12 Italian patients affected with the disease and in healthy family members of one of them. HLA-DR3 was found in 50% of patients as compared to 17.1% of normal control subjects (p = 0.023, relative risk = 4.82). The two relatives also had HLA-DR3 antigen and, in addition, showed equivocal signs of hypertrophy at echocardiographic examination. Thus hypertrophic obstructive cardiomyopathy is associated with genes in the HLA-DR region, and immunogenetic factors could be involved in the pathogenesis of the disease. Furthermore, the minimal target organ abnormalities in "healthy" relatives could represent a subclinical stage of the disease.