Polymorphism of the HLA-B*15 group of alleles is generated following 5 lineages of evolution.

Generation of the HLA-B*15 group of alleles has been analyzed using exon 1, intron 1, exon 2, intron 2, and exon 3 sequences from human and nonhuman primates. Results indicated that the 230 alleles analyzed could be grouped into 5 different lineages of evolution coming from nonhuman primate MHC-B* alleles sharing characteristic nucleotide sequences. The major evolutionary mechanism of evolution in this group of alleles is the gene conversion event with the exchange of genomic sequences present in other HLA-B*alleles.

Human leukocyte antigen-G allele polymorphisms have evolved following three different evolutionary lineages based on intron sequences.

Human leukocyte antigen (HLA)-G alleles follow a different pattern of polymorphism generation from those of the HLA classical I alleles. These polymorphisms have been defined as a result of random permitted point mutations in exons. However, this polymorphism maintenance could have an evolutionary specific pathways based on noncoding regions as introns, 14-bp deletion/insertion (exon 8), or promoter regions.

Heterogeneous expression of HLA-G1, -G2, -G5, -G6, and -G7 in myeloid and plasmacytoid dendritic cells isolated from umbilical cord blood.

Human leukocyte antigen (HLA)-G is a human nonclassic major histocompatibility complex (MHC) molecule characterized by a limited polymorphism and a low, restricted cell surface expression. HLA-G is constitutively expressed on trophoblasts, fetal endothelial, and epithelial cells, conferring alloimmune protection during pregnancy. HLA-G is also expressed in some malignancies and on macrophages and dendritic cells (DC) in tumoral and inflammatory diseases.