A novel HLA-B*51 allele (B*5116) identified by nucleotide sequencing

Area of Science:

• Immunogenetics
• Molecular biology
• Human Leukocyte Antigen (HLA) system

Background:

• The Human Leukocyte Antigen (HLA) system plays a crucial role in immune response and transplantation.
• HLA-B alleles, particularly HLA-B*51, are associated with various autoimmune diseases and drug hypersensitivities.
• Accurate HLA typing is essential for clinical applications such as organ transplantation and disease association studies.

Purpose of the Study:

• To report the identification and characterization of a novel HLA-B*51 allele.
• To describe the specific genetic variations differentiating this new allele from known HLA-B*51 alleles.
• To investigate the preliminary frequency of this new variant in different ethnic groups.

Main Methods:

• Detection of the novel HLA allele using abnormal serological reactivity patterns.
• Confirmation and identification of the allele using Polymerase Chain Reaction with Sequence-Specific Primers (PCR-SSP).
• Detailed characterization of the allele through nucleotide sequencing.

Main Results:

• A new HLA-B*51 variant, designated HLA-B*5116, was identified.
• Nucleotide sequencing revealed two adjacent substitutions in the third exon (positions 216 and 217) compared to HLA-B*5101.
• These substitutions result in a Leucine to Glutamic acid change at codon 163 of the alpha2 domain (CTG-->GAG).
• The HLA-B*5116 variant was not detected in tested French, Algerian, and Lebanese populations, suggesting a very rare frequency.

Conclusions:

• The discovery of HLA-B*5116 expands the known repertoire of HLA-B*51 alleles.
• The specific genetic alterations provide insights into HLA polymorphism and potential functional consequences.
• The apparent rarity of HLA-B*5116 warrants further investigation into its distribution across broader populations and its clinical relevance.