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Host and Plasmodium interactions result in highly variable clinical phenotypes, partly explained by the nature and level of anti-malarial antibody response. Human leukocyte antigen ( HLA)-G can create a tolerogenic environment, allowing parasites to escape from anti-malarial immunity. We performed a family-based association study encompassing 483 Sereer individuals (261 children and their parents), and reported two independent signals at the HLA-G 3′ untranslated region associated with antibody response to specific Plasmodium falciparum blood stage antigens, previously associated with malaria protection: (i) + 3010G together with + 3142C with total IgG and IgG1 against GLURP and (ii) + 3196G with IgG3 against MSP2. While these results require further investigation, they suggest for the first time a role of HLA-G in the regulation of humoral immune response in malaria. [ABSTRACT FROM AUTHOR]

The non-classical human leukocyte antigen (HLA) class I genes present a very low rate of variation. So far, only 10 HLA-E alleles encoding three proteins have been described, but only two are frequently found in worldwide populations. Because of its historical background, Brazilians are very suitable for population genetic studies. Therefore, 104 bone marrow donors from Brazil were evaluated for HLA-E exons 1-4. Seven variation sites were found, including two known single nucleotide polymorphisms (SNPs) at positions +424 and +756 and five new SNPs at positions +170 (intron 1), +1294 (intron 3), +1625, +1645 and +1857 (exon 4). Haplotyping analysis did show eight haplotypes, three of them known as E*01:01:01, E*01:03:01 and E*01:03:02:01 and five HLA-E new alleles that carry the new variation sites. The HLA-E*01:01:01 allele was the predominant haplotype (62.50%), followed by E*01:03:02:01 (24.52%). Selective neutrality tests have disclosed an interesting pattern of selective pressures in which balancing selection is probably shaping allele frequency distributions at an SNP at exon 3 (codon 107), sequence diversity at exon 4 and the non-coding regions is facing significant purifying pressure. Even in an admixed population such as the Brazilian one, the HLA-E locus is very conserved, presenting few polymorphic SNPs in the coding region. [ABSTRACT FROM AUTHOR]

Here we report two new non-classical class I HLA-G alleles found in the Brazilian population. [ABSTRACT FROM AUTHOR]