#51
COMPLETE ALLELE LEVEL HLA TYPING FROM DRIED BLOOD SPOTS USING SSP AND WHOLE GENOME AMPLIFICATION.
Cynthia S. Turino MS 1, Genaro S. Scavello BS 1, Kimberly-Anne Mattia 1 and Valerie McCarro 1. 1 R&D, GenoVision, Inc., West Chester, PA, USA .
The dried blood spot has fulfilled the need of finding a more cost-effective and simple way to transport samples for DNA analysis and is becoming a more frequent sample type in the HLA laboratory. Although convenient for transportation, dried blood samples rarely yield enough DNA for a complete HLA typing with just one extraction. Almost all HLA typing methods require many PCR reactions for a complete A, B, C, DR, and DQ allele level typing, especially the Sequence Specific Priming (SSP) method. SSP is easy, does not need expensive equipment, and can obtain unambiguous allele level typing results without using an alternative method. However, due to the amount of DNA required to perform a complete allele level typing, dried blood samples are usually not suitable for SSP.
Whole genome amplification (WGA) is a novel alternative to multiple DNA extractions. The method uses Phi 29, a processive DNA polymerase that displaces the complementary strands and continues to replicate up to 100 kb without dissociation from the genomic DNA template. 40 
g of WGA DNA can be obtained with as little as 1 ng of genomic DNA.
The purpose of this study was to obtain enough DNA from dried blood spots to perform a complete HLA typing using both low and high resolution SSP kits. DNA extracted from dried blood spots was whole genome amplified. The WGA DNA was used in both low and high resolution SSP kits to determine the HLA-A, B, C, DR, and DQ allele level typing. The WGA DNA typing was compared to the typing obtained from DNA extracted from whole blood. The typings matched exactly with no discrepancies, concluding that WGA DNA is a reliable and efficient way to increase DNA amounts for complete HLA typing results without obtaining additional sample.