Do host factors contribute to the pathogenesis of Acute Rheumatic Fever?
Yes. ARF is most frequent in children (4–15 years). Extreme variations in incidence according to geography exist and are partially explainable by socioeconomic disparities and bacterial serotype variation, but host genetic factors are also contributory. Twin concordance studies suggest overall heritability of 60%. HLA Class II association studies have resulted in conflicting data, although many were performed in relatively low-incidence (European) populations. A genome-wide association study of oceanic populations has suggested a significant risk for IGHV4-61, a heavy chain allele. Expression of a B lymphocyte alloantigen (recognized by the antibody D8/17 ) has been found in 66% to 100% of ethnically diverse ARF patients and 10% of controls.
