The
Human Leukocyte Antigen

Human Leukocyte Antigen (HLA)

Genes that are located in the Major Histocompatibility Complex (MHC) of chromosome 6 and play a central role in immune recognition. Most investigations of association of HLA to various diseases have focused on evaluating HLA allele frequencies in diseases of interest, as compared to the general, healthy population. Such studies have demonstrated HLA involvement with cancer, autoimmune, and in- fectious diseases. HLA Class I proteins (HLA-A, B, C) are expressed on all nucleated cells and present peptides from endogenous proteins to cytotoxic T lymphocytes engaged in immune surveillance. HLA Class II proteins (HLA-DRB1, DRB3/4/5, DQB1, DPB1) are expressed on antigen-presenting cells and present peptides derived from exogenous proteins to CD4+helper T cells. A previous study of Gulf War syndrome in 27 veterans found that HLA DRB1*15 was more prevalent in cases than controls with an odds ratio of 1.66, although this association was not statistically significant.
DRB1*13:02 Allele Protects against Dementia in Continental Western Europe

Journal of Neurology & Neuromedicine - 2019-09-09James L, Georgopoulos AP
HLA Class II DRB1*13 alleles have recently been found to protect against age-related brain deterioration, even in the presence of
Apolipoprotein E

Apolipoprotein E (ApoE)

a plasma lipoprotein discovered in 1973 (Shore and Shore 1973). It binds low-density lipoprotein receptors, thereby facilitating cellular lipoprotein exchange and metabolism. The human apoE polypeptide consists of 299 amino acids and comprises three polymorphisms resulting from single amino acid substitutions. Three isoforms (E4, E3, and E2) are the result of cysteine^aEUR"arginine interchanges at two sites, namely residues 112 and 158; however, other genetic variants have been described. These three isoforms, each differentially affecting protein function, result in six phenotypes: three homozygotes (E4/4, E3/3, E2/2) and three heterozygotes (E4/3, E4/2, E3/2). With respect to the number of cysteine residues per mole, E2/2 contains 4, E3/2 contains 3, E4/2 and E3/3 each contain 2, E4/3 contains 1, and E4/4 contains 0. The number of cysteine residues per mole (CysR/mole) provides a numerical, biochemical scale in lieu of the genotype-based categories.
4 (
ApoE

Apolipoprotein E (ApoE)

a plasma lipoprotein discovered in 1973 (Shore and Shore 1973). It binds low-density lipoprotein receptors, thereby facilitating cellular lipoprotein exchange and metabolism. The human apoE polypeptide consists of 299 amino acids and comprises three polymorphisms resulting from single amino acid substitutions. Three isoforms (E4, E3, and E2) are the result of cysteine^aEUR"arginine interchanges at two sites, namely residues 112 and 158; however, other genetic variants have been described. These three isoforms, each differentially affecting protein function, result in six phenotypes: three homozygotes (E4/4, E3/3, E2/2) and three heterozygotes (E4/3, E4/2, E3/2). With respect to the number of cysteine residues per mole, E2/2 contains 4, E3/2 contains 3, E4/2 and E3/3 each contain 2, E4/3 contains 1, and E4/4 contains 0. The number of cysteine residues per mole (CysR/mole) provides a numerical, biochemical scale in lieu of the genotype-based categories.
4), suggesting a possible protection against dementia. Here we evaluated the association between the population frequency of common DRB1*13 alleles and the prevalence of dementia in Continental Western Europe. Prevalence of dementia in Continental Western Europe was derived from published reports on dementia frequency from the Global Burden of Disease Study 2016 and population totals obtained from the Population Reference Bureau. DRB1*13:01 and DRB1*13:02 allele frequencies were obtained from a publicly available database (allelefrequency.net) and
ApoE

Apolipoprotein E (ApoE)

a plasma lipoprotein discovered in 1973 (Shore and Shore 1973). It binds low-density lipoprotein receptors, thereby facilitating cellular lipoprotein exchange and metabolism. The human apoE polypeptide consists of 299 amino acids and comprises three polymorphisms resulting from single amino acid substitutions. Three isoforms (E4, E3, and E2) are the result of cysteine^aEUR"arginine interchanges at two sites, namely residues 112 and 158; however, other genetic variants have been described. These three isoforms, each differentially affecting protein function, result in six phenotypes: three homozygotes (E4/4, E3/3, E2/2) and three heterozygotes (E4/3, E4/2, E3/2). With respect to the number of cysteine residues per mole, E2/2 contains 4, E3/2 contains 3, E4/2 and E3/3 each contain 2, E4/3 contains 1, and E4/4 contains 0. The number of cysteine residues per mole (CysR/mole) provides a numerical, biochemical scale in lieu of the genotype-based categories.
was obtained from published reports on the world distribution of
ApoE

Apolipoprotein E (ApoE)

a plasma lipoprotein discovered in 1973 (Shore and Shore 1973). It binds low-density lipoprotein receptors, thereby facilitating cellular lipoprotein exchange and metabolism. The human apoE polypeptide consists of 299 amino acids and comprises three polymorphisms resulting from single amino acid substitutions. Three isoforms (E4, E3, and E2) are the result of cysteine^aEUR"arginine interchanges at two sites, namely residues 112 and 158; however, other genetic variants have been described. These three isoforms, each differentially affecting protein function, result in six phenotypes: three homozygotes (E4/4, E3/3, E2/2) and three heterozygotes (E4/3, E4/2, E3/2). With respect to the number of cysteine residues per mole, E2/2 contains 4, E3/2 contains 3, E4/2 and E3/3 each contain 2, E4/3 contains 1, and E4/4 contains 0. The number of cysteine residues per mole (CysR/mole) provides a numerical, biochemical scale in lieu of the genotype-based categories.
4. The prevalence of dementia in 14 Continental Western European (CWE) countries, where life expectancy is practically identical, significantly decreases exponentially with increasing frequency of DRB1*13:02 (R2 = 0.452, P = 0.008), even when adjusted for the prevalence of
ApoE

Apolipoprotein E (ApoE)

a plasma lipoprotein discovered in 1973 (Shore and Shore 1973). It binds low-density lipoprotein receptors, thereby facilitating cellular lipoprotein exchange and metabolism. The human apoE polypeptide consists of 299 amino acids and comprises three polymorphisms resulting from single amino acid substitutions. Three isoforms (E4, E3, and E2) are the result of cysteine^aEUR"arginine interchanges at two sites, namely residues 112 and 158; however, other genetic variants have been described. These three isoforms, each differentially affecting protein function, result in six phenotypes: three homozygotes (E4/4, E3/3, E2/2) and three heterozygotes (E4/3, E4/2, E3/2). With respect to the number of cysteine residues per mole, E2/2 contains 4, E3/2 contains 3, E4/2 and E3/3 each contain 2, E4/3 contains 1, and E4/4 contains 0. The number of cysteine residues per mole (CysR/mole) provides a numerical, biochemical scale in lieu of the genotype-based categories.
4 allele, a known risk factor for Alzheimer's disease. This finding documents the protective effect of DRB1*13:02 on dementia prevalence in CWE. Since the function of
Human Leukocyte Antigen

Human Leukocyte Antigen (HLA)

Genes that are located in the Major Histocompatibility Complex (MHC) of chromosome 6 and play a central role in immune recognition. Most investigations of association of HLA to various diseases have focused on evaluating HLA allele frequencies in diseases of interest, as compared to the general, healthy population. Such studies have demonstrated HLA involvement with cancer, autoimmune, and in- fectious diseases. HLA Class I proteins (HLA-A, B, C) are expressed on all nucleated cells and present peptides from endogenous proteins to cytotoxic T lymphocytes engaged in immune surveillance. HLA Class II proteins (HLA-DRB1, DRB3/4/5, DQB1, DPB1) are expressed on antigen-presenting cells and present peptides derived from exogenous proteins to CD4+helper T cells. A previous study of Gulf War syndrome in 27 veterans found that HLA DRB1*15 was more prevalent in cases than controls with an odds ratio of 1.66, although this association was not statistically significant.
class II genes is to aid in the elimination of pathogens by enabling the production of antibodies against their antigens in specific immunity, the protective effect of DRB1*13:02 points to the presence of persistent harmful antigens as causal factors in development of dementia, antigens specific to DRB1*13:02 that could not be eliminated in its absence.