Philippa C. Matthews, Jennifer Listgarten, Jonathan M. Carlson, Rebecca Payne, Kuan-Hsiang Gary Huang, John Frater, Dominique Goedhals, Dewald Steyn, Cloete van Vuuren, Paolo Paioni, Pieter Jooste, Anthony Ogwu, Roger Shapiro, Zenele Mncube, Thumbi Ndung'u, Bruce D. Walker, David Heckerman, Philip J. R. Goulder

HLA class I genotype is a major determinant of the outcome of HIV infection, and the impact of certain alleles on HIV disease outcome is well studied. Recent studies have demonstrated that certain HLA class I alleles that are in linkage disequilibrium, such as HLA-A*74 and HLA-B*57, appear to function co-operatively to result in greater immune control of HIV than mediated by either single allele alone. We here investigate the extent to which HLA alleles--irrespective of linkage disequilibrium--function co-operatively.