A new HLA-D specificity associated with DR blank: D-BON

Area of Science:

• Immunogenetics
• Histocompatibility
• Human Leukocyte Antigen (HLA) complex

Background:

• A serologically undefined DR blank specificity, segregating in families and linked to DQw1, has been recognized since 1980.
• This undefined specificity poses challenges in human leukocyte antigen (HLA) typing and transplantation compatibility.

Purpose of the Study:

• To characterize a specific DR blank antigen within a Caucasoid family.
• To provisionally define and name this new specificity as D-BON.
• To determine the gene frequency and associations of the D-BON specificity.

Main Methods:

• Analysis of a Caucasoid family (BON) with multiple homozygous individuals for the target specificity.
• Utilizing homozygous typing cells for characterization.
• Serological testing with monomorphic anti-DR monoclonal antibodies.
• Population-based haplotype analysis to estimate gene frequency.

Main Results:

• Four out of eight children in the BON family were homozygous for the D-BON specificity.
• Homozygous D-BON cells express DR molecules, confirmed by reactivity with anti-DR monoclonal antibodies.
• The estimated gene frequency of D-BON is 1-2% in the general population, accounting for approximately 40% of the DR blank frequency.
• D-BON shows associations with DQw1, B35, and C4B2.

Conclusions:

• The D-BON specificity represents a significant component of the previously undefined DR blank antigen.
• The availability of homozygous D-BON typing cells facilitates further immunogenetic research.
• D-BON's association with specific DQw1, B35, and C4B2 alleles provides insights into HLA haplotype linkage.