Markers of susceptibility to acute rheumatic fever: The B-cell antigen D8/17 is not robust as a marker in South Africa
Background Acute rheumatic fever and its chronic sequelae, rheumatic cardiac disease, and neuropsychiatric movement disorders, remain major public health problems in South Africa. Early identification and treatment of streptococcal pharyngitis in susceptible individuals would prevent rheumatic cardiac disease. The B-cell antigen D8/17 is a marker of susceptibility to rheumatic fever in some populations.Methods and results We assessed the significance of the D8/17 marker in a group of South Africans. Blood was collected from 107 individuals; 40 patients had previous confirmed rheumatic fever, 20 were first-degree relatives, and 47 were controls. The expression of D8/17 in each sample was analysed by flow cytometry. The mean proportion of B-cells that were D8/17 positive was 0.5% in the index cases, 0.47% in their relatives, and 0.27% in the controls. There was a significant difference between the index cases and the controls, p = 0.03, but the mean percentage positive in each group was very low.Conclusions Patients with a history of rheumatic fever had statistically increased expression of the D8/17 marker. However, the actual percentages in this observational study were markedly lower than in other populations, ranging from 0.14%-1.53% compared to 11.6%-39.3%. The D8/17 marker would be an impractical screening tool in the South African population. Copyright © Cambridge University Press 2011.