Introduction: In subjects with presenting alleles, chronic infection is dominated by the HLA-B*57-restricted KF11 response and consequent A146X escape mutations that impair virus replicative ability.

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Result: ISW9 epitope polymorphisms comprised the A146X escape in the epitope flanking region (X = G, N, P, S or V); and the I147X compensatory mutations (where X = V, F, W or M), that are known to restore immune recognition of ISW9 (29).

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Result: Polymorphism A146X was found in 13/44 (30%) subjects, and occurred at comparable frequencies across clades A1- (30%, 7/23) and D (29%, 6/21), Table 1.

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