Interferon-alpha receptor-1 (IFNAR1) variants are associated with protection against cerebral malaria in The Gambia

The chromosome 21q22.11 cytokine receptor cluster contains four genes that encode subunits of the receptors for the cytokines interleukin-10 and interferon-alpha, -beta and -gamma that may have a role in malaria pathogenesis. A total of 15 polymorphic markers located within these genes were initially genotyped in 190 controls, and 190 severe malaria cases from The Gambia. Two interferon-alpha receptor-1 (IFNAR1) gene SNPs (17470 and L168 V) showed evidence for an association with severe malaria phenotypes and were typed in a larger series of samples comprising 538 severe malaria cases, 338 mild malaria cases and 562 controls. Both the 17470-G/G and L168V-G/G genotypes were associated with protection against severe malaria, in general, and cerebral malaria, in particular(P = 0.004 and 0.003, respectively). IFNAR1 diplotypes were then constructed for these two markers using the PHASE software package. The (17470-G L 168V-G/17470-G L168V-G) diplotype was found to be associated with a reduced risk of cerebral malaria and the (17470-C L168V-C1/17470-G L168V-G) diplotype with an increased risk of cerebral malaria (overall 3 x 2 chi(2) = 12.8, d.f. = 2, P = 0.002 and 3 x 2 chi(2) = 15.2, d.f. = 2, P = 0.0005, respectively). These data suggest a role for the type I interferon pathway in resistance to cerebral malaria.