B-cell antigen D8/17 is a marker of rheumatic fever susceptibility in Aboriginal Australians and can be tested in remote settings

Objective: To test the B-cell antigen D8/17 as a marker of past rheumatic fever (RF) in a predominantly Aboriginal Australian population, and to evaluate technical modifications to allow its use in remote settings. Design and setting: Cross-sectional survey in a remote Aboriginal community, a regional tertiary referral hospital and a tertiary paediatric centre in Melbourne. Participants: 106 people, including three with acute RF, 38 with a history of past RF, 20 relatives of these people, and 45 healthy controls. Main outcome measure: D8/17 expression in B cells. Results: Blood was c ollected from each participant and the expression of D8/17 and CD19 in each sample was analysed by flow cytometry. The mean proportion of D8/17-positive B cells was 39.3% (SD, 11.8) in patients with previous RF, 22.5% (SD, 5.2) in first-degree relatives, 11.6% (SD, 7.2) in controls, and 83.7% (SD, 10.1) in patients with acute RF (analysis of variance test between means, P=0.001). A cut-off of 22.1% of D8/17-positive B cells to indicate past RF yielded the highest percentage of correct results (95.4%). Delayed staining of whole blood (mean, 0.55 days; SD, 0.2) gave equivalent results to immediate staining, but the D8/17 assay on peripheral blood mononuclear cells was unreliable. Conclusions: The B-cell antigen D8/17 accurately identifies Australians with a past history of RF, and the assay is feasible in remote settings with access to facilities capable of performing D8/17 staining within half a day of sample collection.