HLA typing strategies in a cord blood bank

Area of Science:

• Immunogenetics
• Molecular Biology
• Transplantation Science

Background:

• Serological typing of human leukocyte antigen (HLA) is a standard method but can yield equivocal results, especially with cord blood samples.
• Cord blood samples are often small, of poor quality, and prone to contamination, further complicating serological HLA typing.

Purpose of the Study:

• To evaluate the efficacy of polymerase chain reaction with sequence-specific primers (PCR-SSP) in improving the accuracy of HLA typing for cord blood units (CBU).
• To compare the performance of serological HLA typing with PCR-SSP for CBU.

Main Methods:

• 220 cord blood units (CBU) were initially typed for HLA class I antigens using serological techniques.
• Samples with doubtful serological results were re-typed using PCR-SSP.
• HLA class II alleles were typed exclusively by PCR-SSP.

Main Results:

• Serological typing yielded satisfactory results for 82.3% of samples.
• Doubtful antigen assignments occurred in 23.1% for HLA-A and 56.4% for HLA-B loci with serology.
• PCR-SSP provided clear HLA class I antigen definition in all cases and 100% clear results for HLA class II alleles.

Conclusions:

• PCR-SSP effectively resolves the limitations of serological HLA typing for cord blood.
• While PCR-SSP is superior, it cannot fully replace serology in routine practice currently.
• A combined approach of serological and molecular typing (PCR-SSP) is recommended for accurate and unambiguous cord blood HLA typing.