A double determinant immunoassay for HLA class I typing using serum as an antigen source

Area of Science:

• Immunology
• Genetics
• Biochemistry

Background:

• Human Leukocyte Antigen (HLA) typing is crucial for transplantation and disease association studies.
• Conventional HLA typing methods often rely on viable cells and can be subject to variability.
• Serum-based antigen detection offers a potential alternative for simplified HLA typing.

Purpose of the Study:

• To evaluate the efficacy and reproducibility of a double determinant immunoassay (DDIA) for HLA class I typing using serum.
• To compare DDIA results with conventional HLA typing methods.
• To assess the advantages of DDIA over traditional lymphocytotoxic assays.

Main Methods:

• Application of a double determinant immunoassay (DDIA) for HLA-A2, A28, and B13 typing.
• Utilized serum as the antigen source for the immunoassay.
• Compared DDIA results with conventional HLA typing methods.

Main Results:

• Achieved high correlation with conventional HLA typing: 96% for B13 and 89.1% for A2, A28.
• Demonstrated high reproducibility with concordant results across multiple tests and time points.
• Observed minimal variation (<5%) in HLA-A2 antigen content in serial serum samples from the same donor.
• Identified a sevenfold variation in serum HLA-A2, A28 antigen levels correlated with donor genotype.

Conclusions:

• The DDIA is a sensitive, simple, and reproducible method for HLA class I typing.
• DDIA provides quantitative information on alloantigen levels, unlike conventional assays.
• DDIA eliminates the need for viable cells, enabling retrospective studies and typing of leucopenic patients.