The HLA-C*05 family allele - C*05:142

Area of Science:

• Immunogenetics
• Molecular Biology
• Human Leukocyte Antigen (HLA) System

Background:

• The Human Leukocyte Antigen (HLA) system plays a critical role in immune response and transplantation.
• Identifying novel HLA alleles is crucial for understanding immune diversity and potential clinical applications.
• Previous studies have identified numerous HLA alleles, but new variants continue to be discovered.

Purpose of the Study:

• To report the identification and characterization of a novel HLA-C*05 allele, designated HLA-C*05:142.
• To determine the genetic and serological properties of this new allele.
• To investigate the frequency and potential haplotype associations of HLA-C*05:142.

Main Methods:

• Exon sequencing (exons 2-7) of a potential new HLA-C allele.
• DNA sequencing and analysis to identify nucleotide variations.
• Amino acid sequence analysis to predict functional impact.
• Serological HLA-Cw5 typing using 19 antisera.
• Population frequency analysis based on sequence-based typing data.

Main Results:

• The second identified example of the novel HLA-C*05:142 allele was found in a UK European male.
• HLA-C*05:142 differs from HLA-C*05:01:01:01 by a single nucleotide change (395G>C) in exon 3, resulting in an R108P amino acid substitution.
• Serological typing indicated that HLA-C*05:142 encodes a "normal" Cw5 specificity, with no apparent involvement of position 108 in known HLA-C epitopes.
• The likely associated haplotype is A*02:01~C*05:142~B*44:02.
• The maximum frequency of HLA-C*05:142 is 0.00001 in 34,743 subjects, significantly lower than the C*05:01 allele frequency (0.10441) in local blood donors.

Conclusions:

• A novel HLA-C allele, HLA-C*05:142, has been identified and characterized.
• The identified amino acid substitution does not alter the serological Cw5 specificity.
• HLA-C*05:142 is a rare allele with a distinct haplotype association.