High density FTA plates serve as efficient long-term sample storage for HLA genotyping.

Area of Science:

• Genomics
• Immunogenetics
• Molecular Biology

Background:

• Dried blood spots (DBS) offer a stable alternative to frozen storage for biological samples.
• The suitability of DBS for high-resolution human leukocyte antigen (HLA) allele sequencing remains debated.
• Long-term storage of biological samples impacts DNA quality and downstream applications.

Purpose of the Study:

• To evaluate the efficacy of DNA extraction from DBS stored on FTA plates for high-resolution HLA sequencing.
• To identify optimal DNA extraction methods for maximizing DNA yield and quality from stored DBS.
• To determine if frozen whole blood can be transferred to filter paper without compromising HLA genotyping.

Main Methods:

• DNA extraction from DBS stored for up to four years using six distinct methods.
• High-resolution sequencing of human leukocyte antigen (HLA) alleles.
• Comparison of DNA quality and quantity across different extraction protocols.
• Assessment of HLA genotyping accuracy from long-term stored samples.

Main Results:

• Specific DNA extraction protocols were identified that yield sufficient high-quality DNA from DBS for reliable high-resolution HLA sequencing.
• Frozen whole blood samples stored for several years maintained their suitability for HLA genotyping after transfer to filter paper.
• The storage duration of DBS on FTA plates did not preclude successful high-resolution HLA sequencing when appropriate methods were used.

Conclusions:

• DNA derived from DBS stored on high-density FTA plates is suitable for high-resolution HLA sequencing.
• The selection of appropriate DNA extraction protocols is critical for successful genotyping from stored DBS.
• Transferring long-term stored frozen whole blood to filter paper does not compromise HLA genotyping accuracy.