A new approach to safely type for HLA the HIV infected people eligible to abacavir therapy: Saliva or buccal swab as reliable DNA sources

Background: Increasing the safety in Immunogenetics Labs, in the era of antiretroviral pharmacogenomics, represents an imperative goal. To this purpose, we tested saliva and buccal cells as biological sources of DNA, alternative to peripheral blood, for HLA-B*57:01 genomic typing of HIV positive patients eligible to treatment with abacavir. Methods: Blood, saliva and buccal cells of 20 voluntary donors and 20 HIV positive patients were collected. DNA was extracted with a manual commercial kit and an automated platform. Quality and quantity of DNA was evaluated with different procedures. The suitability and reliability of DNAs for HLA-B*57:01 genotyping was checked at low and high resolution level, using PCR-SSP (sequence specific primers PCR), revPCR-SSO (reverse sequence specific oligonucleotides PCR), bead array and SBT (sequence based typing) techniques. Results: DNA concentrations were qualitatively very good and quantitatively comparable in all the specimens tested with an inferior yield for cotton swabs. Comparing the results of HLA typing with different methodologies, the 100% of reproducibility was achieved. Conclusions: The viral load of buccal epithelial cells or saliva is extremely low. Here we demonstrated that the DNA from these alternative sources is appropriate for HLA-B*57:01 typing. We strongly recommend the use of this procedure to increase the safety in the lab when dealing with infectious samples.